Studies of the Potential Utility of Ki67 as a Predictive Molecular Marker of Clinical Response in Primary Breast Cancer

INTRODUCTION: Objectives were to characterise the relationship of the proliferation marker Ki67 with response to systemic treatment in early breast cancer and to assess its clinical utility, using fine needle aspirates. MATERIALS AND METHODS: Hundred and six women were treated with primary tamoxifen (n = 33), chemotherapy (n = 33) or chemotherapy and tamoxifen (n = 40). Treatment was not randomised and response was assessed clinically. Ki67 was evaluated prior to treatment and at Day 14 or 21 after commencing treatment. To assess reproducibility, Ki67 was evaluated in repeat FNAs taken from 37 untreated patients. RESULTS: The percentage change in Ki67 in first 21 days was different between responders and non-responders for patients treated with tamoxifen (p = 0.007) and chemotherapy (p = 0.005) but not for chemoendocrine treatment (p = 0.062). The reproducibility study indicated that a decrease to 36% or less of the pre-treatment Ki67 value in an individual patient was required for it to be regarded as a statistically significant change. A significant decrease in Ki67 was seen in responding patients treated with chemotherapy (p = 0.026) and chemoendocrine treatment (p = 0.041). Positive and negative predictive values for response were 85 and 59% for chemotherapy patients and 88 and 54% for chemoendocrine patients, respectively. CONCLUSION: Ki67 is unlikely to be useful as a predictive marker in individual patients. Further molecular markers that predict lack of response continue to be required.     

Prediction of clinical outcome from primary tamoxifen by expression of biologic markers in breast cancer patients.

The aim of this study was to evaluate pretreatment clinical features and biological markers together with changes in these factors as predictors of response and relapse in patients receiving tamoxifen for primary breast cancer. Fine-needle aspiration cytology of the primary breast cancer was performed before tamoxifen treatment in 54 patients and repeated after therapy on day 14, day 60, or on both days in a subset of 35 patients. These samples were evaluated for estrogen receptor (ER), progesterone receptor (PgR), Ki67, S-phase fraction and ploidy. The overall response to tamoxifen was 57% (31 of 54 patients). Pretreatment ER and PgR significantly predicted for response by univariate analysis (P < 0.0001 and P < 0.003, respectively). By multivariate analysis, ER expression was the only independent predictor of response, and it was associated with 27 times the likelihood of response (95% confidence interval, 6-136). Increase in PgR and decrease in Ki67 on day 14 significantly predicted for response to tamoxifen (P < 0.03 and P < 0.04, respectively). Lack of ER, clinical node-positive disease, and failure to decrease Ki67 on day 14 were significantly associated with increased risk of relapse (P < 0.05). By multivariate analysis, ER expression was the only independent predictor of relapse (P < 0.005). Pretreatment and early changes in molecular marker expression may assist in the prediction of response and clinical outcome in primary breast cancer patients receiving tamoxifen.     

Proliferation, steroid receptors and clinical/pathological response in breast cancer treated with letrozole

Sixty-three postmenopausal women with large primary breast cancers were treated with neoadjuvant letrozole (2.5 mg daily) for 3 months. Tumour samples were taken at diagnosis and after 10-14 days and 3 months treatment. Immunohistochemical staining for Ki67, oestrogen receptor (ER) and progesterone receptor (PgR) was performed and related to clinical (ClinR) and pathological responses (PathR) after 3 months treatment. ClinR was observed in 48 of 63 cases (76.2%) and PathR in 47 of 62 (75.8%). Pretreatment Ki67 scores were similar in responders (R) and non-responders (NR). Highly significant Ki67 decreases occurred in all tumour subgroups at 10-14 days (P<0.005). A significant difference in Ki67 scores at 10-14 days (P<0.007) was found between PathR and PathNR but not between ClinR and ClinNR. At 3 months, decreases from pretreatment Ki67 scores were highly significant in all tumour subgroups irrespective of response status. However, whereas Ki67 scores were significantly different between pathological R and NR (P = 0.009), the corresponding comparison of ClinR status was not. Significant decreases between 10-14 days and 3 months were found only in ClinR and PathR (P = 0.02 and 0.045, respectively). Treatment significantly reduced PgR expression at 14 days and 3 months (both P<0.0001), but the level of changes was not different between response status groups. In summary, letrozole produces rapid and profound decreases in expression of Ki67 and PgR but changes do not always correlate with clinical and pathological responses.     

Biologic markers as predictors of clinical outcome from systemic therapy for primary operable breast cancer.

PURPOSE: To determine whether pretreatment clinical features and molecular markers, together with changes in these factors, can predict treatment response and survival in patients with primary operable breast cancer who receive neoadjuvant therapy. PATIENTS AND METHODS: Mitoxantrone, methotrexate (with or without mitomycin), and tamoxifen chemoendocrine therapy was administered to 158 patients before surgery. Clinical response was assessed after four cycles of treatment. Fine-needle aspiration cytology for estrogen receptor (ER), progesterone receptor (PgR), c-erbB-2, p53, bcl-2, Ki67, S-phase fraction (SPF), and ploidy were performed pretreatment and repeated on day 10 or day 21 after the first cycle of treatment. RESULTS: Good clinical response (GCR, defined as complete response or minimal residual disease) was achieved in 31% of patients (49 of 158). Tumor size, nodal disease, response, ER, PgR, c-erbB-2, p53, bcl-2, Ki67, SPF, and ploidy were analyzed as predictors of survival. By univariate analysis, node-positive disease (P =.05), lack of ER (P <.05) and PgR (P <.05), and failure to attain GCR (P =.008) were associated with a significantly increased risk of relapse. A significantly increased risk of death was associated with node-positive disease (P =.02), lack of ER expression (P =.04), and failure to attain GCR. By multivariate analysis, GCR was an independent predictor for survival (P =.05). ER expression (P =.03), absence of c-erbB-2 (P =.03), and a decrease in Ki67 on day 10 or day 21 of the first cycle (P <.05) significantly predicted for subsequent GCR. CONCLUSION: Molecular markers may be used to predict the likelihood of achieving GCR, which seems to be a valid surrogate marker for survival.     

Letrozole inhibits tumor proliferation more effectively than tamoxifen independent of HER1/2 expression status

BACKGROUND: The biological basis for the superior efficacy of neoadjuvant letrozole versus tamoxifen for postmenopausal women with estrogen receptor (ER)-positive locally advanced breast cancer was investigated by analyzing tumor proliferation and expression of estrogen-regulated genes before and after the initiation of therapy. METHODS: Tumor samples were obtained at baseline and at the end of treatment from 185 patients participating in a double blind randomized Phase III study of neoadjuvant endocrine therapy. These paired specimens were simultaneously analyzed for Ki67, ER, progesterone receptor (PgR), trefoil factor 1 (PS2), HER1 (epidermal growth factor receptor), and HER2 (ErbB2 or neu) by semiquantitative immunohistochemistry. RESULTS: The treatment-induced reduction in geometric mean Ki67 was significantly greater with letrozole (87%) than tamoxifen (75%; analysis of covariance P = 0.0009). Differences in the average Ki67 reduction were particularly marked for ER-positive tumors that overexpressed HER1 and/or HER2 (88 versus 45%, respectively; P = 0.0018). Twenty-three of 92 tumors (25%) on tamoxifen and 14 of 93 on letrozole (15%) showed a paradoxical increase in Ki67 with treatment, and the majority of these cases was HER1/2 negative. Letrozole, but not tamoxifen, significantly reduced expression of the estrogen-regulated proteins PgR and trefoil factor 1, regardless of HER1/2 status (P < 0.0001). ER down-regulation occurred with both agents, although levels decreased more with tamoxifen (P < 0.0001). CONCLUSION: Letrozole inhibited tumor proliferation to a greater extent than tamoxifen. The molecular basis for this advantage appears complex but includes possible tamoxifen agonist effects on the cell cycle in both HER1/2+ and HER1/2- tumors. A pattern of continued proliferation despite appropriate down-regulation of PgR expression with estrogen deprivation or tamoxifen was also documented. This observation suggests the estrogenic regulation of proliferation and PgR expression may be dissociated in endocrine therapy resistant cells.     

Comparison of the short-term biological effects of 7alpha-[9-(4,4,5,5,5-pentafluoropentylsulfinyl)-nonyl]estra-1,3,5, (10)-triene-3,17beta-diol (Faslodex) versus tamoxifen in postmenopausal women with primary breast cancer

7Alpha-[9-(4,4,5,5,5-pentafluoropentylsulfinyl)-nonyl]estra-1,3,5, (10)-triene-3,17beta-diol (ICI 182,780; Faslodex) is a novel steroidal antiestrogen. This partially blind, randomized, multicenter study compared the effects of single doses of long-acting ICI 182,780 with tamoxifen or placebo on estrogen receptor (ERalpha) and progesterone receptor (PgR) content, Ki67 proliferation-associated antigen labeling index (Ki67LI), and the apoptotic index in the primary breast tumors of postmenopausal women. Previously untreated patients (stages T(1)-T(3); ER-positive or -unknown) were randomized and received a single i.m. dose of ICI 182,780 50 mg (n = 39), ICI 182,780 125 mg (n = 38), or ICI 182,780 250 mg (n = 44) or oral tamoxifen 20 mg daily (n = 36) or matching tamoxifen placebo (n = 43) for 14-21 days before tumor resection surgery with curative intent. The ER and PgR H-scores, together with the Ki67LI were determined immunohistochemically in the matched pretreatment biopsy and the posttreatment surgical specimens. The apoptotic index was determined by terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling on the same samples. The effects of treatment on each of these parameters were compared using analysis of covariance. ICI 182,780 produced dose-dependent reductions in ER and PgR H-scores and in the Ki67LI. The reductions in ER expression were statistically significant at all doses of ICI 182,780 compared with placebo (ICI 182,780 50 mg, P = 0.026; 125 mg, P = 0.006; 250 mg, P = 0.0001), and for ICI 182,780 250 mg compared with tamoxifen (P = 0.024). For PgR H-score, there were statistically significant reductions after treatment with ICI 182,780 125 mg (P = 0.003) and 250 mg (P = 0.0002) compared with placebo. In contrast, tamoxifen produced a significant increase in the PgR H-score relative to placebo, and consequently, all doses of ICI 182,780 produced PgR values that were significantly lower than those in the tamoxifen-treated group. All doses of ICI 182,780 significantly reduced Ki67LI values compared with placebo (ICI 182,780 50 mg, P = 0.046; 125 mg, P = 0.001; 250 mg, P = 0.0002), but there were no significant differences between any doses of ICI 182,780 and tamoxifen. ICI 182,780 did not alter the apoptotic index when compared with either placebo or tamoxifen. Short-term exposure to ICI 182,780 reduces the ERalpha in breast tumor cells in a dose-dependent manner by down-regulating ER protein concentration. The reductions in tumor PgR content by ICI 182,780 demonstrate that ICI 182,780, unlike tamoxifen, is devoid of estrogen-agonist activity. Reductions in tumor cell proliferative activity (as indicated by Ki67LI) show that ICI 182,780 is likely to have antitumor activity in the clinical setting.     

Analysis of Ki‐67 expression with neoadjuvant anastrozole or tamoxifen in patients receiving goserelin for premenopausal breast cancer

BACKGROUND:

The increasing costs associated with large‐scale adjuvant trials mean that the prognostic value of biologic markers is increasingly important. The expression of nuclear antigen Ki‐67, a marker of cell proliferation, has been correlated with treatment efficacy and is being investigated for its value as a predictive marker of therapeutic response. In the current study, the authors explored correlations between Ki‐67 expression and tumor response, estrogen receptor (ER) status, progesterone receptor (PgR) status, and histopathologic response from the STAGE study (S_ tudy of T_ amoxifen or A_ rimidex, combined with G_ oserelin acetate to compare E_ fficacy and safety).

METHODS:

In a phase 3, double‐blind, randomized trial (National Clinical Trials identifier NCT00605267), premenopausal women with ER‐positive, early stage breast cancer received either anastrozole plus goserelin or tamoxifen plus goserelin for 24 weeks before surgery. The Ki‐67 index, hormone receptor (ER and PgR) status, and histopathologic responses were determined from histopathologic samples that were obtained from core‐needle biopsies at baseline and at surgery. Tumor response was determined by using magnetic resonance imaging or computed tomography.

RESULTS:

In total, 197 patients were randomized to receive either anastrozole plus goserelin (n = 98) or tamoxifen plus goserelin (n = 99). The best overall tumor response was better for the anastrozole group compared with the tamoxifen group both among patients who had a baseline Ki‐67 index ≥20% and among those who had a baseline Ki‐67 index <20%. There was no apparent correlation between baseline ER status and the Ki‐67 index in either group. Positive PgR status was reduced from baseline to week 24 in the anastrozole group.

CONCLUSIONS:

In premenopausal women with ER‐positive breast cancer, anastrozole produced a greater best overall tumor response compared with tamoxifen regardless of the baseline Ki‐67 index. Cancer 2013. © 2012 American Cancer Society.     

Steroid hormone receptors and response to high-dose medroxyprogesterone acetate in advanced breast cancer

Forty-six patients with advanced breast cancer were treated with oral high-dose medroxyprogesterone acetate (MPA) as a second line endocrine treatment, with a 28% 13/46) response rate. There was a significant difference in response to MPA between patients with estrogen (ER)- or progesterone (PgR)-receptors and those with negative receptors assayed just before the treatment (ER+, 7/10, ER-, 0/9 of response rates, p = 0.007, PgR+, 4/4: PgR-, 3/15, p = 0.02). The combination of ER and PgR was observed to be best in predicting the response (p = 0.02). The ER status as well as the combination of ER and PgR, but not PgR alone detected in the primary tumors, correlated well with the response (ER+, 10/23: ER-, 0/15, p = 0.0094, PgR+: PgR-, p = 0.13, ER+PgR+, ER+PgR-, ER-PgR-:p = 0.024). The correlation between steroid hormone receptors and response to MPA in advanced breast cancer was established from the literature. Response rate to MPA was shown to be 42% (69/169) in ER+ cancer patients, and 10% (9/90) in ER- cancer patients (p = 0.00004). There was no correlation between PgR status and the response. Changes of receptors were studied in relation to the response. When ER+ or PgR+ tumors retained their positivity until MPA treatment, a good response was obtained, while there were almost no responders if one or both receptors changed from positive to negative, or remained negative. In conclusion, the response to MPA can be predicted by the steroid hormone receptors.     

A pilot study of the effects of short-term tamoxifen therapy on Ki-67 labelling index in women with primary breast cancer

In this study we demonstrate the change in estrogen receptor (ER) level and cell proliferation in human breast cancer after a short-term tamoxifen therapy. Ten pre- and post-treatment breast tumor samples were examined immunohistochemically using ER and Ki-67 antibodies. Before tamoxifen treatment, six (60%) of ten patients were positive for ER. Tamoxifen increased the ER level in one patient and decreased the level in 4 patients. There was no significant change in ER level by tamoxifen therapy. On the other hand, Ki-67 labelling index (LI) significantly decreased after tamoxifen treatment. When Ki-67 LI was analyzed according to ER level, there was no difference between pre- and post-tamoxifen treatment in ER-negative patients, however, a significant decrease of Ki-67 LI by tamoxifen treatment was seen in ER-positive patients. Patients who showed down-regulation of ER expression tended to show a decrease of Ki-67 LI after tamoxifen therapy. In conclusion, short-term tamoxifen therapy decreased the proliferation of breast cancer, in ER-positive breast tumor samples.     

Influence of the antioestrogen tamoxifen on normal breast tissue

Immunohistochemical assays have been employed to study the expression of ER, PgR, EGFR and Ki67 immunostaining in normal breast tissue (n = 76). The expression of ER and PgR was highly variable in both pre and postmenopausal women and was characterised by large numbers of apparently negative cells. This was most evident for ER-ICA staining in tissues removed from premenopausal women. PgR levels were highest in the ducts of premenopausal women, while EGFR expression was elevated in both ducts and lobules. Ki67 expression was observed in less than 10% of all normal cells and was suppressed by the menopause in lobular tissue. Tamoxifen therapy (40 mg d-1) did not influence the expression of PgR, EGFR or Ki67 immunostaining in cancer associated normal tissue (n = 17). A significant increase, however, was observed in the mean percentage ER positivity in ductal tissue. No effect of duration of tamoxifen therapy was observed on the expression of the antigens studied.     

Quantitative changes in cytological molecular markers during primary medical treatment of breast cancer: A pilot study

Aim: To quantify the changes in biological molecular markers during primary medical treatment in patients with operable breast cancer and to assess their possible relationship with response to treatment.Methods: The treatment group consisted of 31 patients with operable breast carcinomas, median age 57 years (range 41–67), treated with four 3weekly cycles of chemotherapy with Mitoxantrone, methotrexate (± mitomycin C), and tamoxifen before surgery. Fine needle aspiration (FNA) was used to obtain samples from patients prior to and at 10 or 21 days posttreatment. The following molecular markers were assessed: estrogen receptor (ER), progesterone receptor (PgR), p53, Bcl2, and Ki67 measured by immunocytochemistry, and ploidy and Sphase fraction (SPF) by flow cytometry. To evaluate the reproducibility of the technique, repeat FNA was performed in a separate nontreatment control group of 20 patients and the same molecular markers assessed, two weeks after the first sample with no intervening treatment.Results: The nontreatment control group showed a high reproducibility for the measurement of molecular markers from repeat FNA. In the treatment group there was a nonsignificant reduction in SPF and a significant reduction (p = 0.005) in Ki67. Patients who responded to neoadjuvant therapy were more likely to have a reduction in these two markers than those who failed to respond. Similarly, a reduction in ER scores was observed between the first and second samples (p = 0.04). For PgR, the change between the first and second samples was not significant although there was a significant difference between responders and nonresponders (p = 0.03). All nine patients with an increase in PgR were responders. No significant changes in p53 or Bcl2 were observed during treatment.Conclusion: Molecular markers can be adequately measured from FNA samples prior to and during neoadjuvant therapy. Changes in cellular proliferation and hormone receptors have been shown that may be related to tumour response. These relationships should be assessed in a larger cohort of patients.     

Cytological evaluation of biological prognostic markers from primary breast carcinomas

This study was undertaken to evaluate our abilityto detect multiple molecular markers of prognosis andresponse to treatment in fine needle aspirates (FNA)from patients with primary breast carcinomas. 147 patientswith operable primary breast carcinomas who had beenrecruited to a randomized trial of primary medicaltherapy (PMT) versus adjuvant chemoendocrine therapy were analysed.FNAs were taken prior to therapy and fromthis multiple slides were produced using cytospin cytocentrifugationand stored at – 80 °C for subsequentimmunocytochemical analysis (ICA). ICA was performed for oestrogenreceptor (ER), progesterone receptor (PgR), p53, Ki67, andBcl-2. Part of the aspirate was snap frozenand used for flow cytometric analysis of ploidyand S-phase fraction (SPF). In a subgroup of50 patients who had surgery prior to systemictherapy, as well as FNAs, sections were alsotaken from paraffin-embedded blocks and stained by ICAfor ER, PgR and p53 for validation. Inthese patients ER was additionally measured by enzymeimmunoassay (EIA) from frozen tissue taken at surgery.ER, PgR, p53, Bcl-2, and Ki67 were successfullydetected by ICA while ploidy and SPF weresuccessfully measured by flow cytometry from FNA material.The percentage positive values obtained were reasonable andas follows: 74% for ER, 70% for PgR,36% for p53, 80% for Bcl-2. 68% oftumours were aneuploid and 32% diploid. Significant relationshipsbetween these measurements were observed in accordance withexpectations. The concordance for ER, PgR, and p53from FNA when compared to ICA of matchinghistological sections was 91.5%, 75.5%, and 75% respectively.For ER the concordance between measurement by ICAof cytological and histological samples and by EIAof frozen tissue was 82.5% and 84% respectively.These results indicate that multiple molecular markers canbe adequately tested on cytological preparations from primarybreast tumours. These markers can be used todetermine prognosis and predict response to PMT.     

Estrogen receptor (ER) and progesterone receptor (PgR), by ligand-binding assay compared with ER, PgR and pS2, by immuno-histochemistry in predicting response to tamoxifen in metastatic breast cancer: a Southwest Oncology Group Study

Results of estrogen receptor (ER) and progesterone receptor (PgR) ligand-binding assays (LBAs) are strongly correlated with ER and PgR by immuno-histochemistry (IHC). To investigate whether ER and PgR by IHC are also strongly correlated with tamoxifen response, time to treatment failure (TTF) and overall survival (OS), the results of the 2 methods were directly compared in 205 patients with ER(+) metastatic breast cancer treated with daily tamoxifen (Southwest Oncology Group protocol 8228) with 9 years median follow-up. pS2, another estrogen-regulated molecule, was also analyzed. Tumors were scored for IHC from 0 to 5, according to the proportion of positively stained cells. These IHC scores for both ER and PgR were significantly associated with LBA levels (p < 0.001). There was a significant direct relationship between higher IHC ER, PgR and pS2 and increasing response to tamoxifen. TTF and OS were also significantly longer for patients with higher ER or PgR, but not pS2, IHC scores. Low, intermediate and high ER or PgR categories showed similar differences in response rates whether defined by LBA or IHC. In logistic regression models which included ER, PgR and pS2 by IHC; ER and PgR by LBA; and menopausal status, only ER (IHC) and pS2 (IHC) retained significance for predicting tamoxifen response (p = 0. 02 and p = 0.005, respectively), along with menopausal status (for PgR by IHC, p = 0.09). Increasing ER and PgR by IHC, as by LBA, are thus significantly associated with a progressively better response and longer survival in ER(+) metastatic breast cancer. pS2 is also predictive in this setting.     

Dose-dependent change in biomarkers during neoadjuvant endocrine therapy with fulvestrant: results from NEWEST, a randomized Phase II study

NEWEST (Neoadjuvant Endocrine Therapy for Women with Estrogen-Sensitive Tumors) is the first study to compare biological and clinical activity of fulvestrant 500 versus 250 mg in the neoadjuvant breast cancer setting. We hypothesized that fulvestrant 500 mg may be superior to 250 mg in blocking estrogen receptor (ER) signaling and growth. A multicenter, randomized, open-label, Phase II study was performed to compare fulvestrant 500 mg (500 mg/month plus 500 mg on day 14 of month 1) versus fulvestrant 250 mg/month for 16 weeks prior to surgery in postmenopausal women with ER+ locally advanced breast cancer. Core biopsies at baseline, week 4, and surgery were assessed for biomarker changes. Primary endpoint: change in Ki67 labeling index (LI) from baseline to week 4 determined by automated computer imaging system (ACIS). Secondary endpoints: ER protein expression and function; progesterone receptor (PgR) expression; tumor response; tolerability. ER and PgR were examined retrospectively using the H score method. A total of 211 patients were randomized (fulvestrant 500 mg: n = 109; 250 mg: n = 102). At week 4, fulvestrant 500 mg resulted in greater reduction of Ki67 LI and ER expression versus 250 mg (-78.8 vs. -47.4% [p < 0.0001] and -25.0 vs. -13.5% [p = 0.0002], respectively [ACIS]); PgR suppression was not significantly different (-22.7 vs. -17.6; p = 0.5677). However, H score detected even greater suppression of ER (-50.3 vs. -13.7%; p < 0.0001) and greater PgR suppression (-80.5 vs. -46.3%; p = 0.0018) for fulvestrant 500 versus 250 mg. At week 16, tumor response rates were 22.9 and 20.6% for fulvestrant 500 and 250 mg, respectively, with considerable decline in all markers by both ACIS and H score. No detrimental effects on endometrial thickness or bone markers and no new safety concerns were identified. This provides the first evidence of greater biological activity for fulvestrant 500 versus 250 mg in depleting ER expression, function, and growth.     

Comparison of the results of immunocytochemical assays for biologic variables on preoperative fine-needle aspirates and on surgical specimens of primary breast carcinomas

BACKGROUND: Fine-needle aspiration biopsy (FNAB) is a well-documented procedure for the diagnosis and biologic characterization of breast carcinoma. In order to compare the immunocytochemical expression of biologic parameters on cytology and on histology, estrogen receptor (ER) and progesterone receptor (PgR) status, p53 protein expression, and Ki67 growth fraction were evaluated on presurgical fine-needle aspirates (FNAs) from breast carcinoma patients and on the corresponding surgical samples prior to any systemic therapy. METHODS: FNAs were performed on 104 patients with primary breast carcinoma at the time of diagnosis and subjected to immunocytochemical evaluation of ER, PgR, p53, and Ki67. The same parameters were immunohistochemically evaluated on the corresponding paraffin embedded sections. RESULTS: ER, PgR, p53, and Ki67 were evaluable on FNAs and on paired tissue sections in 100, 97, 68, and 84 cases, respectively. Concordance between cytology and histology was 89% for ER, 78% for PgR, 79% for p53, and 70% for Ki67. CONCLUSIONS: The concordance between the results of immunocytochemical evaluation of ER, PgR, p53, and Ki67, on both cytology and histology, underscores the reliability of the biologic characterization of breast carcinoma by FNAB. This approach could be particularly useful in predicting prognosis and response to treatment in patients who are candidates for neoadjuvant chemotherapy and/or endocrine therapy.     

Relationship between estrogen receptor,progesterone receptor,HER-2 and Ki67 expression and efficacy of aromatase inhibitors in advanced breast cancer

BackgroundSurprisingly few data are published on the relevance of even commonly used biomarkers of response to aromatase inhibitors (AIs) in advanced breast cancer. Here, we aim to determine the effectiveness of AIs in that setting according to quantitative levels of estrogen receptor (ER), progesterone receptor (PgR) and Ki67 or human epithelial growth factor receptor-2 (HER-2) status.Patients and methodsER, PgR, HER-2 and Ki67 protein expressions were centrally assessed in 177 archival formalin-fixed paraffin-embedded primary or locally recurrent breast tumours from women who subsequently received AI treatment of advanced disease.ResultsAmong ER-positive patients (n = 146), higher PgR, but not ER, levels were associated with increased time to AI treatment failure (TTF). Higher Ki67 staining was associated with decreased TTF. ER-positive/HER-2-positive patients showed a non-significant trend for decreased TTF compared with ER-positive/HER-2-negative patients. PgR level, but not Ki67, remained a significant predictor of TTF in multivariate analysis of ER-positive patients.ConclusionsHigher PgR and Ki67 levels are significantly associated with increased and decreased TTF, respectively, in ER-positive patients receiving AI treatment of advanced disease. The higher proliferation seen in PgR-negative tumours does not explain the poorer clinical responsiveness of this subgroup.     

Baseline breast tissue characteristics determine the effect of tamoxifen on mammographic density change

Tamoxifen prevents recurrence of breast cancer and is also approved for preventive, risk-reducing, therapy. Tamoxifen alters the breast tissue composition and decreases the mammographic density. We aimed to test if baseline breast tissue composition influences tamoxifen-associated density change. This biopsy-based study included 83 participants randomised to 6 months daily intake of placebo, 20, 10, 5, 2.5, or 1 mg tamoxifen. The study is nested within the double-blinded tamoxifen dose-determination trial Karolinska Mammography Project for Risk Prediction of Breast Cancer Intervention (KARISMA) Study. Ultrasound-guided core-needle breast biopsies were collected at baseline before starting treatment. Biopsies were quantified for epithelial, stromal, and adipose distributions, and epithelial and stromal expression of proliferation marker Ki67, oestrogen receptor (ER) and progesterone receptor (PR). Mammographic density was measured using STRATUS. We found that greater mammographic density at baseline was positively associated with stromal area and inversely associated with adipose area and stromal expression of ER. Premenopausal women had greater mammographic density and epithelial tissue, and expressed more epithelial Ki67, PR, and stromal PR, compared to postmenopausal women. In women treated with tamoxifen (1–20 mg), greater density decrease was associated with higher baseline density, epithelial Ki67, and stromal PR. Women who responded to tamoxifen with a density decrease had on average 17% higher baseline density and a 2.2-fold higher PR expression compared to non-responders. Our results indicate that features in the normal breast tissue before tamoxifen exposure influences the tamoxifen-associated density decrease, and that the age-associated difference in density change may be related to age-dependant differences in expression of Ki67 and PR.     

Role of biologic markers in patient selection and application to disease prevention

Aromatase inhibitors (AIs) are now under investigation for the treatment of early stage breast cancer and for disease prevention as alternatives to standard treatment with tamoxifen. Currently identified genetic risk factors of breast cancer include BRCA-1/BRCA-2 mutations, ATM mutations, and history of high estrogen levels, as evidenced by plasma analyses and/or dense bones. To date, estrogen receptor (ER) and progesterone receptor (PgR) status has predictive value for determining response to therapy in patients with hormone receptor-positive breast cancer (ER+ and/or PgR+ tumors). Recent studies have shown AIs to be safer and more effective than tamoxifen in postmenopausal women with advanced disease. Some data suggest that letrozole may be a more effective treatment than tamoxifen for patients with ER+ and/or PgR+ early breast cancers expressing ErbB-1 and/or ErbB-2. Changes in cell proliferation markers (e.g., S-phase fraction and Ki67 antigen), plasma lipid levels, and the bone resorption marker C-terminal peptide are biomarkers that have been evaluated for preventive and prognostic value in breast cancer patients and normal volunteers. Results from biomarker screens can be used to define inclusion criteria for clinical trials and eventually to individualize treatment. Gene expression profiling (microarray analysis), i.e., genomic and proteomic studies, will probably advance the discovery of new biomarkers for breast cancer prevention and treatment.     

Immunohistochemical evaluation of hormone receptor status for predicting response to endocrine therapy in metastatic breast cancer

BACKGROUND: The importance of establishing hormone receptor status of tumors for the treatment of women with hormone receptor-positive breast cancer has been emphasized, however, there is no general agreement as to how immunohistochemical assays should be evaluated. It is critical to evaluate hormone receptor status when considering response to endocrine therapy. METHODS: Estrogen receptor (ER) and progesterone receptor (PgR) expression was examined by immunohistochemistry using Allred's score for primary breast tumors from 75 metastatic breast cancer patients who received first-line treatment with endocrine therapy (56 patients received tamoxifen, 11 patients received aromatase inhibitors, and 8 patients received LH-RH agonist or other endocrine reagents) on relapse. Correlation between hormone receptor status and response to endocrine therapy as well as post-relapse survival was analyzed. RESULTS: The most significant correlation between positive ER expression and response to any endocrine therapy (p = 0.011) or tamoxifen only (p = 0.030) occurred when the cutoff score was set at 10%. When the evaluation was based on Allred's score (TS), a cutoff point of TS>or=4 showed a more significant association between positive ER expression and response to all kinds of endocrine therapy (p = 0.020) or tamoxifen only (p = 0.047). When evaluated at a cutoff point of 1% positive cells, there were fifteen patients with both ER- and PgR-negative tumors, and three patients (20.0%) responded to the therapy. Patients with 1% or more ER or PgR positive cells had better survival after relapse (p = 0.0005 and p = 0.0008, respectively). CONCLUSIONS: The proportion score alone might be enough to predict hormone responsiveness and post-relapse survival in metastatic breast cancer. The cutoff might be set low, for example 1%, especially for metastatic disease.     

Effect of tamoxifen on Ki67 labelling index in human breast tumours and its relationship to oestrogen and progesterone receptor status.

This study aimed to investigate the effect of tamoxifen on breast tumour levels of oestrogen and progesterone receptor (ER and PR) and proliferation as defined by the Ki67 antibody. A group of primary breast cancer patients was randomised to receive either tamoxifen (n = 59) or placebo (n = 44) treatment in the interval between clinic and surgery (median 21 days). Frozen sections of breast tumour biopsies obtained before and after treatment were stained immunocytochemically to obtain the percentage of nuclei containing ER and PR, and a Ki67 labelling index (LI). Tamoxifen-treated patients had a median Ki67 LI of 5.6% in the first biopsy falling to 3.0% in the second biopsy (P < 0.001 by Wilcoxon''s matched pairs test), whereas placebo-treated patients had a median Ki67 LI of 5.4% in the first biopsy and 5.75% in the second (no significant difference). No significant differences were observed when the median %ER or %PR staining before and after treatment were compared. The Ki67 LI tended to increase with increasing histological grade and was greater in tumours that were ER - ve compared to those that were ER + ve (> 5% nuclei stained), median 7.8% and 4.3% respectively (P = 0.011 by Mann-Whitney U-test). However, the decline in tumour Ki67 LI following anti-oestrogen treatment failed to correlate with ER and PR status or to predict recurrence over a short follow-up period. To our knowledge, this is the first time that tamoxifen treatment has been shown to reduce the Ki67 LI in human breast tumours in vivo. These data indicate that staining with the Ki67 antibody may be useful in monitoring response to anti-oestrogen therapy.