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.     

Measurement of steroid hormone receptors in breast cancer patients on tamoxifen

Summary Estrogen (ER) and progesterone receptor (PgR) positive breast tumors often respond to tamoxifen, but ultimately progress as they become tamoxifen resistant. An accurate assessment of receptor status in specimens from tamoxifen-resistant patients could help to understand potential mechanisms of resistance and to predict response to second line hormonal therapies. However, since tamoxifen itself can affect ER and PgR determinations, assay results can be misleading. We measured ER and PgR by both ligand binding (LBA) and immunohistochemical (IHC) assays in 34 tumors from patients on tamoxifen, 30 of whom were displaying resistance to the drug. These tumors were classified into several receptor phenotypes. Eleven patients, 8 of whom were clearly progressing, expressed both receptors while on tamoxifen. ER was significantly less often negative when measured by IHC, suggesting that ER status by LBA was falsely negative in this group due to receptor occupancy by tamoxifen. Six patients had no detectable ER by LBA or IHC but still expressed PgR. The presence of PgR suggests that ER could still be functional, though undetectable, in these tumors, or that PgR is constitutively expressed by them. Finally, 12 patients were ER and PgR-negative by both assays, suggesting hormonal independence as the mechanism for resistance in this group. In a subset of patients with receptor assays both prior to tamoxifen and at the time of progression while taking the drug, we found that most ER-positive tumors converted to an apparent ER-negative status when assayed by LBA, while PgR status frequently remained unchanged. The continued expression of ER and/or PgR in many patients with tumor progression on tamoxifen indicates that mechanisms for resistance other than receptor loss are common in breast cancer.Deceased     

Significance of immunohistochemical assessment of steroid hormone receptor status for breast cancer patients

The assessment of steroid hormone receptors in resected breast cancer tissues is essential to decide whether endocrine therapy is indicated and to select the best treatment for each patient on the basis of receptor status. Both enzyme immunoassay (EIA) and immunohistochemistry (IHC) have been generally used as methods for examination of estrogen receptor (ER) and progesterone receptor (PgR). In some patients, receptor status cannot be examined for various reasons. A questionnaire survey in Japan clarified that ER status is not examined in approximately 40% of patients receiving breast conserving surgery. To eliminate "receptor unknown" cases, IHC examination on paraffin-embedded tissue is useful to assess the in situ receptor status. The concordance rate of ER and PgR status between EIA and IHC is very high and a study of 88 cases revealed a 97.7% concordance for ER and 92.0% for PgR at a cutoff point of 10%. The cutoff point of IHC is controversial and some studies demonstrated that patients showing 1% ER positive cancer cells would benefit from endocrine therapy. On the other hand, immunohistochemical expression of receptors is heterogeneous and some patients with ER negative invasive tumors have ER positive intraductal components. A study of 65 breast cancers demonstrated that ER positive intraductal components were detected in 3.1% cases of ER negative invasive lesions. According to these results and the recommendation of the St. Gallen International Conference, IHC is thought to be more useful than EIA in the assessment of steroid hormone receptor status for breast cancer patients.     

Body size and breast cancer prognosis in relation to hormone receptor and menopausal status: a meta-analysis

Obesity is associated with poor survival after breast cancer diagnosis in individual studies and meta-analyses. Evidence regarding associations of obesity with breast cancer-specific survival (BCSS) and overall survival (OS) in relation to hormone receptor status, or BCSS in relation to menopausal status has not been evaluated in a previous meta-analysis. In this study, we conducted a meta-analysis of the association of obesity with OS and BCSS in relation to hormone receptor status and menopausal status. MEDLINE, EMBASE, and COCHRANE databases from the first record to December 2011 and presentations made at major international meetings in the last 5 years were searched. We included observational or interventional studies reporting hazard ratios (HRs) of obesity with OS and/or BCSS in relation to hormone receptor and/or menopausal status. Twenty-one studies qualified, meeting the above criteria. The pooled HR for OS in heavier versus lighter women was 1.31 (95 % CI 1.17-1.46) for estrogen receptor/progesterone receptor (ER/PgR) positive cancers; 1.18 (95 % CI 1.06-1.31) for ER/PgR negative cancers; and the difference between the two groups was not significant (p = 0.31). The pooled HR for OS in heavier versus lighter women was 1.23 (95 % CI 1.07-1.42) for premenopausal women and 1.15 (95 % CI 1.06-1.26) for post-menopausal women, and the difference between the two groups was not significant (p = 0.57). Comparable pooled HRs for BCSS were 1.36 (95 % CI 1.20-1.54) for ER/PgR positive cancers and 1.46 (95 % CI 0.98-2.19) for ER/PgR negative cancers; and 1.18 (95 % CI 0.82-1.70) for pre-menopausal women and 1.38 (95 % CI 1.11-1.71) for post-menopausal women, also without significant group differences. Results were similar after adjustment for BMI measurement technique, years of follow-up, or study design. These findings led us to conclude that there is no evidence showing that the association of obesity with breast cancer outcome differs by hormone receptor or menopausal status. This has implications for studies of weight loss interventions in the adjuvant BC setting.     

Relationship of PS2 with response to tamoxifen therapy in patients with recurrent breast cancer.

PS2, an oestrogen-inducible protein, was measured in the cytosol of 230 primary tumours from patients who were subjected to first-line tamoxifen therapy for advanced disease without prior adjuvant therapy with tamoxifen. PS2 correlated positively with oestrogen receptor (ER, P < 0.01) and progesterone receptor content (PgR, P < 0.001), and with the length of progression-free survival (PFS, P = 0.05). Although not statistically significant, higher levels of PS2 (> or = 10 ng mg-1 protein) were also associated with increased probability of response to tamoxifen treatment and a longer total post-relapse survival (PRS). ER, PgR, menopausal status, site of disease and prior adjuvant chemotherapy were all associated with response to tamoxifen therapy and with PFS. In multivariate analysis for PFS, low levels of ER and PgR, visceral metastasis, a disease-free interval of less than 1 year and prior adjuvant chemotherapy were all significantly associated with an increased probability of a rapid disease progression after start of tamoxifen therapy. In the subset of 83 tumours with intermediate levels of ER and PgR (both > or = 10, but not both > or = 75 fmol mg-1 protein), PS2 was positively related with the length of PFS (P < 0.01) and PRS (P < 0.05). PS2 remained the strongest factor in multivariate analysis for PFS (P < 0.01) in this ER/PgR intermediate subgroup, but was not of predictive value in univariate or multivariate analysis for both PFS and PRS in tumours classified as ER/PgR low or high (> or = 75 fmol mg-1 protein). It is concluded that PS2 status may be used as a parameter, additional to ER and PgR, for better refinement of prediction of response to tamoxifen treatment in advanced breast cancer patients especially with intermediate ER/PgR levels in their primary tumour.     

Prognostic value of estrogen receptor status can be improved by combined evaluation of p53, Bcl2 and PgR expression: an immunohistochemical study on breast carcinoma with long-term follow-up

Steroid receptor analysis is the only widely accepted prognostic/predictive marker in breast cancer (BC) treatment. In the present study we evaluated the prognostic role of ER/PgR with p53 and Bcl2, in a series of 277 BC (153 pN1/2, 122 pNO, 2 pNx) with a long-term follow-up (67 months for DFS, 75 months for OS). Our results, besides confirming the usefulness of ER immunohistochemical expression as a prognostic marker, showed that PgR expression alone had a borderline/not significant prognostic value in the whole series (p=0.08 for DFS and p=0.09 for OS), while showed to be prognostic in N+ cases (p=0.02 for DFS and p=0.03 for OS). PgR prognostic value, however, was not independent at the multivariate analysis. By combining ER with PgR, p53 and Bcl2, we showed that ER/p53 and ER/Bcl2 phenotypes had a better discriminant role than ER/PgR phenotype. The ER+/p53+ phenotype was at higher risk of relapse/death as compared with ER+/p53- phenotype. Conversely ER-/p53+ phenotype showed the most unfavourable prognosis. Similar results could be observed concerning ER/Bcl2 phenotypes. Our study showed that the combined evaluation of ER/PgR weakly enhanced the prognostic/predictive power of ER status alone. On the contrary, the combined evaluation of ER/p53 and ER/Bcl2, improved this prognostic/predictive capability and allowed the separation of ER positive and ER negative cases into subgroups with different prognosis.     

P(185/Her2) and ps2 protein overexpression in breast-cancer specimens - improvement for prediction of response to endocrine therapy

Simultaneous analyses of p(185/Her2) and pS2 protein expression in breast cancer is discussed to add information about prognosis and response to endocrine treatment. In a retrospective study, expression of p(185/Her2) and pS2 protein were detected by immunohistochemistry in paraffinembedded, formalin-fixed sections of 219 primary breast cancers. Median age was 56.6 years, median follow-up 168 months. Results were correlated with clinical parameters and steroid receptor status. ER was positive in 55%, PgR in 54% of the tumors. ER correlated inversely with tumor size, and with tumor grade. pS2 was detected in 54% of the tumors, but showed no correlations with other parameters. p(185/Her2) was present in 24% of the tumors and correlated positively with tumor size. pS2 and ER or PgR status correlated (p<0.001). In the sub-group of negative steroid receptors and positive pS2 a qualitative significant difference for p(185/Her2) expression was seen. ER, pS2 and p(185/Her2) status had no prognostic impact on disease-free or overall survival; PgR status correlated with clinical outcome.     

Results of two or five years of adjuvant tamoxifen correlated to steroid receptor and S-phase levels

A Swedish cooperative trial demonstrated that 5 years of adjuvant tamoxifen was more beneficial than 2 years of tamoxifen in the treatment of postmenopausal women with estrogen receptor (ER) positive, early stage, invasive breast cancer. The main aim of the present study was to investigate the importance of progesterone receptor (PgR) and ER concentration levels for patients participating in the trial and still distant recurrence free two years after the primary operation. Subgroup analyses revealed that only patients with ER positive and PgR positive breast cancer had improved distant recurrence free survival (DRFS) by prolonged tamoxifen therapy (p=0.0016). Patients with ER negative and PgR negative as well as ER positive and PgR negative tumors showed no significant effect of prolonged tamoxifen (p=0.53 and p=0.80, respectively). The percentage of ER negative and PgR positive breast cancers was too small (2.2%) for any meaningful subgroup analysis. There was a significant positive trend that the concentration level of PgR (high positive vs. low positive vs. negative) decreased the recurrence rate for those with prolonged therapy. No corresponding pattern was found for the ER content. S-phase fraction did not correlate to the recurrence rate of PgR positive breast cancers. Patients recurring during tamoxifen therapy had receptor negative tumors to a greater extent than those recurring after tamoxifen treatment.In conclusion, prolonged tamoxifen therapy for 5 years instead of 2 years was found to be beneficial for patients with ER positive and PgR positive breast cancer, whereas three extra years of tamoxifen had little or no effect for patients with ER positive but PgR negative tumors as well as for steroid receptor negative patients.     

Estrogen and progesterone receptor assay in paraffin-embedded breast cancer--reproducibility of assessment

Immunohistochemical (IHC) assays are routinely used for determining the estrogen receptor (ER) and progesterone receptor (PgR) status of women with breast cancer. The present knowledge of reproducibility of the subjective IHC assessment is limited. The purpose of this study was to evaluate the interobserver reproducibility in IHC assessment of 127 (ER) and 126 (PgR) cases of primary breast cancer. The slides were independently re-assessed by 22 pathologists from nine hospitals. A simple assessment protocol was used with a cut-off value > 10% stained nuclei, regardless of staining intensity. The concordance was high, with a kappa value of 0.78 for ER and 0.72 for PgR. Since some of the 22 pathologists considered one or several sections to be inevaluable, the evaluation comprised three groups (< or = 10% vs. > 10% vs. not evaluated). Although the percentage of positive cases varied among the 22 pathologists (ER: 57%-79%; PgR: 41%-66%), the overall concordance was good for both ER and PgR (kappa = 0.78 and 0.72, respectively). A further improvement in concordance should be possible to achieve through training.     

ER,PgR, HER-2, Ki-67, topoisomerase IIα, and nm23-H1 proteins expression as predictors of pathological complete response to neoadjuvant chemotherapy for locally advanced breast cancer

The purpose of this study was to evaluate the importance of biological markers to predict pathologic complete response (pCR) to neoadjuvant chemotherapy (NCT) in patients with locally advanced breast cancer (LABC) One hundred and twelve consecutive patients with clinical stage III LABC who had received NCT with docetaxel and epirubicin from March 2006 to March 2009 were included in this retrospective study. The pre-NCT treatment expression levels of Ki-67 proliferation index, estrogen receptor (ER), progesterone receptor (PgR), epidermal growth factor receptor 2 (HER-2), Topoisomerase II alpha (Topo-II), and nm23-H1 were detected by immunohistochemistry (IHC). A total of 361 cycles were administered with the median number of three cycles per patient (range, 2–6). The pCR rate was 9.8% (95% CI, 4.3–15.3%). In univariate analysis, poor tumor differentiation, both negative of ER/PgR, negative Topo-II, and positive nm23-H1 were found to be significantly predictive of a pCR. ER/PgR status and nm23-H1 were significant for pCR on multivariate analysis (P = 0.006 and 0.025, respectively). ER/PgR status and nm23-H1 are independent predictive factors of pCR to neoadjuvant docetaxel plus epirubicin combination chemotherapy in patients with LABC.     

Receptor status variation in primary breast cancer and subsequent accessible relapse

To better understand the prognostic relevance of change in steroid receptor status, during the clinical course of breast cancer, we analysed the variation of estrogen and progesterone receptor (ER, PgR) status in a series of 532 primary tumors and metachronous accessible recurrences in individual patients. A more consistent variation was observed in patients with a receptor-positive primary (ER(+) or PgR(+)) than in those with a receptor-negative tumor (ER(-) or PgR(-)). Forty-four percent of PgR(+) and 24% of ER(+) tumors became negative, whereas only 20% of ER(-) or PgR(-) became positive. The changes were independent of tumor stage and menopausal status. However, steroid receptor variation appeared to be related to the interval between the primary tumor and relapse. In fact, the changes from ER(+) to ER(-) were more frequent in patients with a disease-free survival of less than 1 year, whereas changes from ER(-) to ER(+) occurred more often in patients with a disease-free survival of more than 3 years. Moreover, we observed a decrease in the number of ER(+) tumors following hormone treatment and a decrease in ER(-) tumors following chemotherapy. However, such variations did not reach statistical significance. Irrespective of the type of adjuvant therapy, the presence of at least one receptor (in particular, PgR) in the metachronous lesion was correlated with a long median time to relapse and to death. Our results confirmed the predictive relevance of receptor status of the primary lesion on relapse and survival and suggest the predictive relevance of receptor status of the metachronous lesion on post-relapse survival.     

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.     

Prognostic value of estrogen and progesterone receptors in primary breast cancer

Estradiol receptor alone or estradiol and progesterone receptors (ER, PgR) have been measured in tumors from 307 women who were treated for primary breast adenocarcinoma. Patients received adjuvant therapy in relation to tumor stage independently of receptor status. Over a relatively short follow-up, more recurrences are recorded in patients with ER+ tumors, but at 7 years the same proportion of recurrences are registered in both groups of patients whose tumors were ER+ or ER-. Patients whose tumors were processed for both ER and PgR (148 cases) have now been evaluated after 5 years follow-up. Among 56 patients with PgR+ tumors 5 recurred, versus 22/92 in the PgR- group. 21/87 patients who had 1 to 4 invaded nodes at the time of surgery relapsed: 17/54 had PgR- tumors versus 4/33 PgR+. 6 recurrences were recorded in the 61 patients with negative nodes: 5 of them occurred in patients with PgR- tumors. In addition, recurrences observed in patients with negative receptor status occurred after a shorter disease-free interval. Analysis of the incidence of recurrences in relation to the combined ER/PgR status in patients who did not receive adjuvant therapy suggests that tumor PgR content is a more significant criterion than ER for long-term prognosis.     

Immunohistochemical Profile of Breast Cancer Patients at a Tertiary Care Hospital in New Delhi,India

Background: To assess the immunohistochemical expression of estrogen receptor (ER), progesterone receptor(PgR) and human epidermal growth factor receptor-2 (HER2) neu receptor in breast cancer and their associationswith various clinicopathological characteristics. Materials and Methods: This is a retrospective analysis of womenwho presented with primary, unilateral breast cancer in the Department of Medical Oncology at Rajiv GandhiCancer Institute and Research Centre, Delhi, India during the period from January 2008 to December 2011. Datawere retrieved from the medical records of the hospital including both early and locally advanced cancer cases.ER, PgR and HER2neu expression in these patients was assessed and triple negative patients were identified.Associations of triple negative and non-triple negative groups with clinicopathological characteristics were alsoevaluated. Results: A total of 1,284 women (mean age 52.1 years, 41.9% premenopausal) were included in theanalysis. Hormone receptor positivity (ER and/or PgR) was seen in 63.4% patients, while 23.8% of tumors weretriple negative. Only 23.0% were HER2 positive. Around 10.0% of tumors were both ER and HER2 positive.ER and PgR positivity was significantly associated with negative HER2 status (p-value <0.0001). Younger age,premenopausal status, higher tumor grade, lymph node negativity, advanced cancer stage, and type of tumorwere strongly associated with triple negativity. Significantly, a smaller proportion of women had ductal carcinomain situ in the triple negative group compared with the non-triple negative group (35.6% versus 60.8%, p-value<0.01). Conclusions: The present analysis is one of the largest studies from India. The majority of the Indianbreast cancer patients seen in our hospital present with ER and PgR positive tumors. The triple negative patientstended to be younger, premenopausal, and were associated with higher tumor grades, negative lymph nodesstatus and lower frequency of ductal carcinoma in situ.     

Comparison of immunohistochemical and biochemical measurement of steroid receptors in primary breast cancer: Evaluation of discordant findings

Tumor samples of 240 patients with primary breast cancer were biochemically and immunohistochemically investigated for estrogen receptors (ER) and, in 130 of the samples, for progesterone-receptors (PgR) in order to examine reasons for discordant findings. The biochemical (DCCA) and immunohistochemical assays (ICA) yielded positivity in 71% for ER, and in 44% for PgR. Concordant ER-DCCA and ER-ICA results were obtained in 84%; two thirds of the discordant ER-findings manifested as DCCA-neg/ICA-pos. Concordance in the case of PgR amounted to 72%, and of the discordances 60% were DCCA-neg/ICA-pos. Significant association with postmenopausal status existed only for ER positivity in ICA (p=0.01), whereas ER-DCCA, PgR-DCCA and PgR-ICA were all more or less independent of the menopausal status. The frequency of discordances was independent of menopausal status. Discordance for ER-assays increased significantly near the respective cut-off point; this was not unequivocally true for PgR-assays. The correlation of tumor types of sparse cellularity, as well as prominent stroma content (scirrhous carcinoma) with increased frequency of the constellation DCCA-neg/ICA-pos was of borderline significance for PgR (p=0.06), but not for ER. The percentage of discordant ER-findings, figuring as DCCA-neg/ICA-pos, was statistically significantly increased in locally advanced breast cancer (p=0.03). Fibrocystic disease in peritumoral breast tissue had no impact on receptor-assay discordance. In any case, the models derived from theoretical thought, laboratory data and singular observations can only in part explain the discordance in steroid receptor values measured with different methods.     

Incidence and prognostic significance of receptor discordance between primary breast cancer and paired bone metastases

ER, PgR and HER-2 status are the cornerstones of choosing systemic therapy for breast cancer, but can change during the disease course. Guidelines recommended the biopsy of the metastatic tumor to reassess receptor status. Bone is the most frequent metastatic site of breast cancer but remained technically difficult to biopsy. Our study aimed to evaluate the incidence and prognostic significance of receptor discordance between primary breast cancer and paired bone metastases. One hundred and fifty-five breast cancer patients were diagnosed with pathology-confirmed bone metastasis at Fudan University Shanghai Cancer Center. Ninety-three patients with receptor status available on both primary tumor and bone metastases were included in our study. ER, PgR and HER-2 status converted from positive to negative in 10.8% (10/93), 28.0% (26/93) and 8.6% (8/93) of the patients, while ER, PgR and HER-2 status converted from negative to positive in 3.2% (3/93), 4.3% (4/93) and 1.1% (1/93) of the patients, respectively. 40.4% (17/42) of the HER2-0 tumors converted to HER2-low, which enabled them to receive the treatment of new antibody-drug conjugates (ADCs). Prior endocrine and anti-HER2 therapy were the independent risk factors for receptor conversion. Loss of HR expression in bone metastases was significantly associated with worse first-line PFS (adjusted hazard ratio = 3.271, P-value = .039) and OS (adjusted hazard ratio = 6.09, P-value = .011). In conclusion, our study confirmed that patients may experience receptor conversion between primary breast cancer and bone metastases, possibly influenced by prior treatments, which significantly influenced prognosis. The rebiopsy of bone metastases in patients with primary HER2-0 tumors may benefit from the new ADC drugs.     

The prognostic value and relationships of patient characteristics, estrogen and progestin receptors, and site of relapse in primary breast cancer

Estrogen and progestin receptor levels (ER and PgR) in tumors from 506 patients with primary breast cancer diagnosed in 1979, 1980, and 1981 were measured by a Scatchard plot analysis. At a median follow-up time of 3.5 years the prognostic value of the receptor levels was evaluated and compared with other tumor and patient characteristics. No relation was found between receptor levels and tumor, lymph node, metastasis (TNM) classification or location of the primary tumor. A significant positive rank correlation was observed between ER and PgR levels (rs = 0.57) and between ER level and age of the patients (rs = 0.39, P less than 0.001). The observed association between ER level and menopause status could not be maintained after correction for age. Independent prognostic factors for overall survival were tumor size (P = 0.002), the number of positive lymph nodes (P less than 0.001), age at primary surgery (P less than 0.001), the PgR level of the tumor (P less than 0.001), but not ER level. Independent prognostic factors for relapse were tumor size (P = 0.003), number of positive lymph nodes (P less than 0.001), age (P = 0.006), menopause status (P = 0.02), PgR level (P = 0.007), but not ER level. Finally, for death rate after relapse the following prognosticators were identified: size of the primary tumor (P = 0.03), number of positive lymph nodes (P = 0.03), age (P = 0.003), site of relapse (P less than 0.001), ER level (P = 0.02), and PgR level (P = 0.04). Patients with tumors containing low positive PgR levels (10 to 20 fmol/mg protein) had a slightly better prognosis than patients with PgR-negative tumors. It is concluded that the PgR level of the primary tumor is a better prognosticator than the ER level. The ER offered no additional ability for discriminating between low- and high-risk patients once PgR was included in the model. In contrast, PgR was capable of improving on the discriminating ability of ER. In addition, patients with tumors containing both PgR and ER showed the best prognosis. Therefore, it is recommended that ER and PgR should be assayed in all breast cancer biopsies.     

Progesterone receptor loss identifies Luminal B breast cancer subgroups at higher risk of relapse

BackgroundThe immunohistochemical (IHC) evaluation of estrogen receptor (ER), progesterone receptor (PgR), Ki-67 and HER2 is considered a surrogate means for identifying the molecular subtypes of breast cancer with different prognosis.Patients and methodsWe explored patterns of recurrence in 4837 women with breast cancer defined as Luminal B (ER-positive and/or PgR-positive, HER2 positive and/or Ki-67≥14%) by IHC classification. We evaluated four subgroups within the Luminal B subtype according to HER2 expression and PgR status.ResultsPatients within the ER+/PgR+/HER2- subgroup presented a 5-year breast cancer-related survival (BCS) of 97% (95% confidence interval (CI), 96–97) and overall survival (OS) of 95% [95% CI, 95–96], the best survivals of the Luminal B subgroups. In the multivariate analysis, the ER+/PgR-/HER2- subgroup was associated with a reduced BCS (HR 1.71; 95%CI, 1.25–2.35) and OS (HR 1.47; 95%CI, 1.10–1.96) when compared with the ER+/PgR+/HER2- subgroup. Also patients within the ER+/PgR-/HER2+ subgroup had a reduced BCS (HR 1.93; 95%CI, 1.32–2.83) and OS (HR 1.62; 95%CI, 1.14–2.30) when compared with ER+/PgR+/HER2- subgroup. On the other hand, no statistically significant differences were found with regard to BCS and OS among patients with ER+/PgR+/HER2+ and patients with ER+/PgR+/HER2- disease.ConclusionsPgR loss identifies Luminal B breast cancer subgroups at higher risk of relapse and death, both with HER-2-positive and HER-2-negative disease.