Prognostic significance of proliferation associated nucleolar antigen P120 in human breast carcinoma.

Nucleolar antigen P120 is detected in rapidly proliferating cells but not in normal resting cells or in many benign and slowly growing malignant tumors. The objective of the study was to determine whether the expression of P120 in breast cancer correlated with histopathological or biological properties associated with prognosis. In this retrospective study, 120 primary breast tumors were analyzed for P120; 114 of these tumors were also stained for the erbB-2 protein. Immunopositive staining was correlated with patient survival, nodal status, estrogen receptor levels, and number of mitoses. Sixty-nine % (83 of 120) of the tumors were positive for P120; 25% (28 of 114) stained positively for erbB-2. Of the 28 erbB-2 positive tumors 26 were also positive for the P120 protein. Forty-six % (55 of 120) of the specimens were from patients who later died from recurrent breast cancer; P120 was detected in 89% (49 of 55) of these specimens. In 52% of the survivors the P120 protein was also expressed. P120 negative tumors were highly correlative with survival (P = 0.0001); 84% (32 of 37) of patients with P120 negative tumors survived more than 7 years without evidence of recurrent disease. Multivariate analysis showed that the worst prognosis was for patients who had tumor positive nodes and expressed P120 (P = 0.0001); death occurred in 73% (30 of 41) of these patients. For the node negative patients who did not express P120, 5-year survival was 90% (19 of 21 patients); 5-year survival for the node negative patients who expressed P120 was significantly less (67%; 28 of 42 patients). Patients with P120 negative tumors had a good prognosis, irrespective of their nodal status. In this group, survival of node negative patients was 86% (18 of 21) and for those with positive nodes survival was 82% (13 of 16). A poor prognosis was found for patients with intense erbB-2 stained tumors (5 of 7 patients died). Weak staining of erbB-2 tumors (21 specimens) was not correlated with patient survival. Compared to P120 negative tumors, P120 positive tumors had greater numbers of mitoses (9.06 versus 6.65) and an almost 2-fold increase in the occurrence of positive nodes (one of every 4.67 versus one of every 8.81). The number of P120 positive tumors was greater in estrogen receptor positive tumors (75%) than in estrogen negative tumors (54%).(ABSTRACT TRUNCATED AT 250 WORDS)     

miRNA-34a is associated with docetaxel resistance in human breast cancer cells

Docetaxel is a chemotherapy drug to treat breast cancer, however as with many chemotherapeutic drugs resistance to docetaxel occurs in 50% of patients, and the underlying molecular mechanisms of drug resistance are not fully understood. Gene regulation through microRNAs (miRNA) has been shown to play an important role in cancer drug resistance. By directly targeting mRNA, miRNAs are able to inhibit genes that are necessary for signalling pathways or drug induced apoptosis rendering cells drug resistant. This study investigated the role of differential miRNA expression in two in vitro breast cancer cell line models (MCF-7, MDA-MB-231) of acquired docetaxel resistance. MiRNA microarray analysis identified 299 and 226 miRNAs altered in MCF-7 and MDA-MB-231 docetaxel-resistant cells, respectively. Docetaxel resistance was associated with increased expression of miR-34a and miR-141 and decreased expression of miR-7, miR-16, miR-30a, miR-125a-5p, miR-126. Computational target prediction revealed eight candidate genes targeted by these miRNAs. Quantitative PCR and western analysis confirmed decreased expression of two genes, BCL-2 and CCND1, in docetaxel-resistant cells, which are both targeted by miR-34a. Modulation of miR-34a expression was correlated with BCL-2 and cyclin D1 protein expression changes and a direct interaction of miR-34a with BCL-2 was shown by luciferase assay. Inhibition of miR-34a enhanced response to docetaxel in MCF-7 docetaxel-resistant cells, whereas overexpression of miR-34a conferred resistance in MCF-7 docetaxel-sensitive cells. This study is the first to show differences in miRNA expression, in particular, increased expression of miR-34a in an acquired model of docetaxel resistance in breast cancer. This serves as a mechanism of acquired docetaxel resistance in these cells, possibly through direct interactions with BCL-2 and CCND1, therefore presenting a potential therapeutic target for the treatment of docetaxel-resistant breast cancer.     

ESR1 amplification is rare in breast cancer and is associated with high grade and high proliferation: a multiplex ligation-dependent probe amplification study

Background

Expression of estrogen receptor alpha (ERα) is predictive for endocrine therapy response and an important prognostic factor in breast cancer. Overexpression of ERα can be caused by estrogen receptor 1 (ESR1) gene amplification and was originally reported to be a frequent event associated with a significantly longer survival for ER-positive women treated with adjuvant tamoxifen monotherapy, which was however questioned by subsequent studies.

Methods

This study aimed to reanalyze the frequency of ESR1 amplification by multiplex ligation-dependent probe amplification (MLPA) and fluorescence in situ hybridisation (FISH), and to assess clinicopathologic correlations. MLPA was performed in a group of 135 breast cancer patients, and gains/amplifications were subjected to FISH.

Results

True ESR1 amplification by MLPA was rare (2%) and only 6% more patients showed a modest gain of ESR1. All MLPA-detected ESR1 amplifications and nearly all ESR1 gains were also FISH amplified and gained, but not all FISH amplifications/gains were MLPA amplified/gained, leading to an overall concordance of only 60% between both techniques. All 3 MLPA and FISH ESR1 amplified cases had high ERα expression, but there was no obvious correlation between ESR1 gain and ER status by IHC. ESR1 gains/amplifications were not associated with HER2 gain/amplification, but seemed to be associated with older age. Surprisingly, ESR1 gain/amplification was not associated with low grade as reported previously, but correlated with high grade and high proliferation. Furthermore, ESR1 gain/amplification by MLPA was not associated with nodal status or tumor size (pT status).

Conclusions

ESR1 amplification as detected by MLPA is rare in breast cancer, and seems to be associated with high ERα expression, high age, high grade and high proliferation. This study confirms previous studies that showed differences in the ESR1 amplification frequencies detected by different techniques.     

STK15 F31I polymorphism is associated with breast cancer risk: a meta-analysis involving 25,014 subjects

Published data on the association between STK15 F31I polymorphism and breast cancer risk are inconclusive. In order to derive a more precise estimation of the relationship, a meta-analysis was performed. Medline, PubMed, Embase, Web of Science, and Chinese Biomedicine Database were searched. Crude ORs with 95% CIs were used to assess the strength of association between the STK15 F31I polymorphism and breast cancer risk. The pooled ORs were performed for codominant model (FI vs. FF; II vs. FF), dominant model (FI + II vs. FF), and recessive model (II vs. FI + FF), respectively. A total of 10 studies including 10,537 cases and 14,477 controls were involved in this meta-analysis. Overall, significantly elevated breast cancer risk was associated with II variant genotype in homozygote comparison and recessive genetic model when all studies were pooled into the meta-analysis (for II vs. FF: OR = 1.23, 95% CI = 1.10–1.37; for recessive model: OR = 1.21, 95% CI = 1.05–1.40). In the subgroup analysis by ethnicity, significantly increased risks were found for II allele carriers among Caucasians (for II vs. FF: OR = 1.24, 95% CI = 1.08–1.43; for recessive model: OR = 1.21, 95% CI = 1.00–1.45); significantly increased risks were also found among Asians for II versus FF (OR = 1.21; 95% CI = 1.01–1.45). In conclusion, this meta-analysis suggests that the STK15 31II allele is a low-penetrant risk factor for developing breast cancer.     

Glomeruloid microvascular proliferation is associated with lack of response to chemotherapy in breast cancer

Background:

Glomeruloid microvascular proliferation (GMP), a novel histology-based angiogenesis marker, has been associated with decreased survival in several human cancers.

Methods:

In this study, we evaluated the ability of GMP to predict clinical response to neoadjuvant chemotherapy in a series of locally advanced breast cancers (n=112).

Results:

Presence of GMP (21% of the cases) was significantly associated with high-grade tumours and TP53 mutations in addition to the basal-like and HER2 subtypes of breast cancer as defined by gene expression data. GMP was correlated to a gene expression signature for tumour hypoxia response. The GMP pattern was also significantly associated with lack of treatment response and progressive disease (P=0.004).

Interpretation:

The findings suggest that GMP might be able to predict the lack of response to neoadjuvant chemotherapy in locally advanced breast cancer. Whether GMP may be an independent predictor compared with other factors including TP53 mutation status and tumour grade needs confirmation in larger studies.     

Benign thyroid disease is associated with breast cancer: a meta-analysis

The controversial relationship between benign thyroid diseases and breast cancer (BC) has been investigated for over 50 years. Despite extensive population studies, the results as a whole have been inconsistent. The purpose of this study was to collate and analyse available data, calculating a pooled odds ratio (OR) of the risk of BC in patients diagnosed with benign thyroid diseases. Studies were obtained from a database search of MEDLINE, EMBASE, PubMed, Current Contents Connect and Google Scholar with additional cross checking of reference lists. Inclusion criteria required a confirmed diagnosis of a benign thyroid disease, reporting of an OR or data to calculate an OR (and 95% confidence interval, CI) and the use of an internal control group as the comparator. Collated data was assessed for heterogeneity and a pooled OR calculated. 28 studies were included in the meta-analysis. There was significant evidence of an increased risk of BC in patients with autoimmune thyroiditis, evident in a pooled OR 2.92 (95% CI 2.13-4.01). In addition, the results supported an increased risk associated with the presence of anti-thyroid antibodies (OR 2.02, 95% CI 1.63-2.50) and goitre (OR 2.26, 95% CI 1.39-3.69). Subgroup analysis of antibody presence revealed increased risk associated with both anti-TPO (OR 2.64, 95% CI 1.82-3.83) and anti-TG (2.71, 95% CI 1.58-4.69). Quantitative analysis of hypothyroidism and hyperthyroidism was not significant. While these results indicate an association between thyroid auto-immunity and BC, further prospective studies are required to definitively prove causality.     

The R72P P53 mutation is associated with familial breast cancer in Jewish women

BRCA1/BRCA2 mutations account for a substantial proportion of familial breast cancer, but clearly mutations in additional genes exist, one candidate being the p53 gene. To evaluate its putative involvement in inherited predisposition to breast/ovarian cancer in Jewish high-risk women, mutational analysis of the p53 gene (exons 4-9) was carried out using exon-specific polymerase chain reaction followed by denaturing gradient gel electrophoresis (DGGE) analysis, complemented by DNA sequencing of abnormally migrating fragments. Overall, 132 Jewish breast cancer patient non-BRCA1/2 mutation carriers and 167 average risk controls (Ashkenazi (n=60), non-Ashkenazi (n=107)) were genotyped, and no inactivating p53 germline mutations were detected. Consistent migration abnormalities were noted in 167 fragments, 134 of which were shown to be the Arg72Pro polymorphism, whereas migration abnormalities in fragments containing exons 4 (n=2) and 6 (n=23) and introns 3 (n=4) and 9 (n=4) corresponded to five previously described polymorphisms. Allele distribution of the R72P missense mutation between ethnically diverse Jewish breast cancer cases and average risk controls showed significant differences: among non-Ashkenazi breast cancer cases, 62.5%, 33.3% and 4.2% were homozygous, heterozygous and homozygous for the Arg72, Arg72Pro and the Pro72 polymorphism, respectively, whereas for controls, the distribution was 22.4%, 65.4% and 12.2%, respectively (P=0.00052), and among Ashkenazi breast cancer cases, allele distribution was 68.5%, 29.6% and 1.9%, whereas for controls, the distribution was 50%, 40% and 10%, respectively (P=0.0125). We conclude that arginine homozygosity at codon 72 of the p53 gene is associated with a significant increased breast cancer risk in Jewish high-risk population.     

Vascular proliferation is a prognostic factor in breast cancer

Angiogenesis is important for the growth and spread of malignant tumors, and anti-angiogenesis treatment is currently being evaluated for breast cancer and other tumors. Although microvessel density is the most commonly used tissue-based marker of tumor associated angiogenesis, it has significant limitations and has not proven effective as a predictive factor in selecting patients for treatment. We here wanted to explore the significance of vascular endothelial cell proliferation in breast carcinoma. We examined microvessel proliferation in breast cancer by dual immunohistochemical staining, using the pan-endothelial marker Factor-VIII combined with proliferation of endothelial cells by Ki-67 expression, in three independent series of breast cancer, including a total of 499 patients and 141 events during follow-up. Common statistical tests of associations as well as univariate and multivariate regression analysis of patient survival were used. By counting vessels with actively proliferating endothelium, we show that microvascular proliferation is a significant predictor of disease progression in breast cancer, especially among high-grade and ER-negative tumors. Our findings indicate that this novel marker of active tumor angiogenesis might be of value in patient management and should be further studied in the context of patient selection for anti-angiogenesis treatment.     

Aberrant cytoplasmic expression of the p16 protein in breast cancer is associated with accelerated tumour proliferation.

The p16 protein plays an important role in the transition of cells into the G1 phase of the cell cycle. We have studied the prevalence of p16 protein expression in breast carcinomas in a prospective series of 368 invasive and 52 non-invasive malignancies, as well as in 88 locally recurring tumours and three tumour cell lines. p16 protein expression was evaluated immunohistochemically on paraffin sections using monoclonal and polyclonal anti-p16 antibodies, and by immunoblotting of tumour cell suspensions. Tumour cell lines were also subjected to polymerase chain reaction-single strand polymorphism (PCR-SSCP) analysis and direct DNA sequencing. The results were compared with established prognostic parameters, DNA flow cytometry and p53 protein expression. In 33 (9%) invasive and two (4%) intraductal carcinomas, a cytoplasmic accumulation of the p16 protein was seen. These cases were characterized by poor histological grade of differentiation, loss of of oestrogen receptors and progesterone receptors and frequent overexpression of the p53 protein. In addition, breast carcinomas with aberrant p16 expression demonstrated a high proliferative activity, with median S-phase fractions 74% higher than in the control group and the median Ki67 fractions elevated to 75%. A genetic alteration of the p16 gene was not detectable in three analysed cell lines with cytoplasmic p16 expression applying PCR-SSCP and direct DNA sequencing. These results indicate that cytoplasmic accumulation of the p16 protein identifies a subset of highly malignant breast carcinomas with accelerated tumour proliferation and other unfavourable parameters in breast cancer. The described protein accumulation is apparently not caused by an alteration of the p16 gene.     

PLC-beta2 is highly expressed in breast cancer and is associated with a poor outcome: a study on tissue microarrays

Despite the identification of many putative biomarkers in breast cancer, a specific pattern of proteins to be used as a prognosticator is not well defined. A growing body of evidence supports the role of phospholipase C (PLC) in the invasion and metastasis of different tumors, including breast cancer. To assess whether the expression of specific PLC isoforms correlates with malignancy-related features of human breast tumors and, hence, could have prognostic significance, an immunohistochemical analysis of PLC-beta2 was performed on tissue microarrays and the relationship between PLC-beta2 expression and biological and clinico-pathological factors was assessed. The analysis of 77 samples of breast tumors with different histotypes revealed that PLC-beta2 is highly expressed in a large majority of the analyzed cancer tissue, particularly ductal and lobular carcinomas, in comparison with normal breast. The expression of PLC-beta2 in primary tumors correlated with size, proliferation index and final grade, while no significant relationship was observed with nodal status or estrogen receptor levels, or with the expression of tumor suppressor p53. Remarkably, high PLC-beta2 levels in primary tumors predict an unfavourable prognosis, suggesting the contribution of this protein to the progression of human mammary carcinomas. Our data indicate that PLC-beta2 expression correlates highly with breast cancer malignancy and suggest that it can be included, as an independent marker, among the prognostic indicators in current use.     

Serum enterolactone concentration is not associated with breast cancer risk in a nested case-control study

The lignan enterolactone produced by the intestinal microflora from dietary precursors has been hypothesized to protect against hormone-dependent cancers. We conducted a nested case-control study to examine the relationship between serum enterolactone concentration and risk of breast cancer. Enterolactone concentrations were measured by time-resolved fluoroimmunoassay in serum collected at 4 independent cross-sectional population surveys from 206 women with breast cancer diagnosed during follow-up (mean 8.0 years) and from 215 controls frequency-matched to cases by study cohort, 5-year age group and study area. Mean serum enterolactone concentration (nmol/l) did not significantly differ between case and control subjects [25.2 (SD 22.2) vs. 24.0 (SD 21.3), respectively]. Odds ratios for breast cancer risk estimated by conditional logistic regression for increasing concentration of enterolactone in quartiles were 1.00 (referent), 1.67 (95% CI 0.95-2.95), 1.71 (95% CI 0.96-3.06) and 1.30 (95% CI 0.73-2.31), and p for trend was 0.48. Our findings do not support the hypothesis that high serum enterolactone concentration is associated with reduced risk of breast cancer.     

Digoxin treatment is associated with an increased incidence of breast cancer: a population-based case-control study

Introduction  

Laboratory and epidemiologic studies have suggested a modifying effect of cardiac glycosides (for example, digoxin and digitoxin) on cancer risk. We explored the association between digoxin treatment and invasive breast cancer incidence among postmenopausal Danish women.     

P7 antigen expression in human breast cancer.

PURPOSE: Evaluate p7 expression in human breast cancer and determine whether chemotherapy and radiation therapy effect a change in p7 expression. EXPERIMENTAL DESIGN: Using a p7-specific monoclonal antibody with immunohistochemistry and Western immunoblot analyses to assess p7 expression in archival, frozen breast cancer specimens both before and after therapy. RESULTS: A novel 7 kDa protein (p7), originally identified in multidrug-resistant ovarian and breast cancer cell lines, was found to be expressed in 21 of 64 (32%) primary, unselected human breast cancer specimens by immunohistochemistry with the use of a p7-specific monoclonal antibody, 1D7. P7 was observed in malignant cells but not in other types of cells in the breast tissue. Western blot analysis confirmed the 7 kDa polypeptide in p7-positive breast carcinomas identified by immunohistochemistry. P7 expression was significantly associated with breast cancers having distant metastasis and/or local recurrence (P = 0.027, Fisher's exact test). In addition, p7 expression was significantly increased in post-treatment breast cancer biopsy specimens compared with pretreatment breast cancer biopsy specimens in patients with locally advanced breast cancer after 5-fluorouracil chemotherapy and radiation therapy [2 of 15 (13%) pretreatment breast cancers compared with 8 of 15 (53%) post-treatment breast cancers; P = 0.016, McNemar's test]. CONCLUSIONS: These findings demonstrate that expression of p7 is associated with malignant tumor cells in primary breast cancers, especially those showing recurrent or metastatic disease. Its specific association with the malignant phenotype suggests it may have potential for novel target-based therapies. The markedly increased expression in patients with locally advanced disease after neoadjuvant therapy suggests a role for p7 in treatment outcome.     

Amyloid precursor protein in human breast cancer: An androgen‐induced gene associated with cell proliferation

Amyloid precursor protein (APP) is a transmembrane protein that is highly expressed in brain tissue. Recently, APP has been implicated in some human malignancies, and its regulation by androgens has also been demonstrated. Such findings suggest the importance of APP in hormone‐dependent breast carcinoma, but APP has not yet been examined in breast carcinoma tissues. Therefore, in this study, we examined the biological and clinical significance of APP in breast carcinoma using immunohistochemistry and in vitro studies. APP immunoreactivity was detected in 57 out of 117 (49%) breast carcinoma tissues examined, and it was positively associated with androgen receptor (AR) expression. APP immunoreactivity was also significantly associated with Ki‐67 LI and increased risk of recurrence in the estrogen receptor (ER)‐positive cases, and was an independent prognostic factor in these patients. Subsequent in vitro experiments demonstrated that APP mRNA expression was significantly induced by biologically active androgen dihydrotestosterone in both a dose‐dependent and a time‐dependent manner in MCF‐7 breast carcinoma cells, which was potently suppressed by an AR blocker hydroxyflutamide. Moreover, cell proliferation activity of MCF‐7 and MDA‐MB‐231 cells was significantly associated with their APP expression level. These findings suggest that APP is an androgen‐induced gene that promotes proliferation activity of breast carcinoma cells. Moreover, APP immunohistochemical status is considered a potent prognostic factor in ER‐positive breast cancer patients.     

Expression of bone sialoprotein in primary human breast cancer is associated with poor survival

We have recently demonstrated that bone sialoprotein (BSP), a bone-matrix protein involved in hydroxyapatite crystal formation, is ectopically expressed in human breast cancers. We explored a possible association between expression of BSP in primary breast cancer and patients' survival. We analyzed BSP expression in 454 breast-cancer patients by immunohistochemistry on archival paraffin-embedded material using an anti-BSP polyclonal antibody. BSP expression was correlated to survival, tumor size, axillary lymph-node status and first site of distant metastasis. Of the breast cancers analyzed, 89% expressed detectable amounts of BSP. We found a statistical association between expression of BSP and poor prognosis as indicated by survival curves analyzed using the log rank and the Gehan methods. BSP expression was significantly higher in breast-cancer patients with axillary lymph-node involvement. Interestingly, survival of patients with positive lymph nodes but BSP-negative tumors was significantly higher than that of patients with no lymph-node involvement but BSP-positive cancers. The frequency of bone metastases was higher in the group of patients with BSP-positive tumors (22%) than in the group with BSP-negative cancers (7%). There was a significant increase in the incidence of lung metastases in patients whose tumors were negative for BSP. Our data show that bone sialoprotein expression in breast cancer is associated with poor prognosis. BSP detection also appears to be a valuable marker with which to identify, among the lymph-node-negative patients, those who have high risk of disease progression. © 1996 Wiley-Liss, Inc.     

Down-regulation of microRNA-200c is associated with drug resistance in human breast cancer

Drug resistance remains a major clinical obstacle to successful treatment in breast cancer patients, and the evidence of microRNAs involvement in cancer drug resistance has been emerging recently. However, the role of microRNA-200c (miR-200c) in modulating chemoresistance of breast cancer remains largely unexplored. Here, we investigated the miR-200c expression in tumor specimens obtained from thirty-nine breast cancer patients who received neoadjuvent chemotherapy by quantitative real-time PCR. Down-regulated miR-200c was observed in non-responders as compared to responders. In addition, miR-200c expression was observed to be down-regulated over 800-fold in human breast cancer cells resistant to doxorubicin MCF-7/ADR as compared to the parental MCF-7 cells. Up-regulation of miR-200c with transfection of miR-200c mimics in breast cancer cells could enhance the chemosensitivity to epirubicin and reduce expression of multidrug resistance 1 mRNA and P-glycoprotein. Moreover, our study demonstrated that restoration of miR-200c in MCF-7/ADR cells could increase intracellular doxorubicin accumulation determined by flow cytometry. Taken together, our findings suggest that miR-200c may act as a promising therapeutic target for improvement of responsiveness to chemotherapy in breast cancer.     

Expression of enhancer of zeste homologue 2 is significantly associated with increased tumor cell proliferation and is a marker of aggressive breast cancer.

The polycomb group protein enhancer of zeste homologue 2 (EZH2) has been linked to invasive properties of aggressive breast cancer. In this report, tissue microarray analysis of 190 breast carcinomas from a nested case-control study shows that EZH2 is significantly associated with interval breast cancers. Further, a strong relationship was found with tumor cell proliferation (by Ki-67 expression), locally advanced disease, metastasis at presentation, markers of the basal epithelial phenotype (positivity for cytokeratin 5/6 or P-cadherin), and p53 status. EZH2 expression was also significantly associated with glomeruloid microvascular proliferation, an aggressive angiogenic phenotype. For prediction of aggressive disease (any event of locally advanced disease, lymph node spread, or distant spread), EZH2 was the only variable of significance in multivariate analysis, whereas no additional information was given by Ki-67. Although EZH2 expression was significant in univariate survival analysis, only tumor cell proliferation and lymph node status were significant in the final multivariate model. In conclusion, our findings indicate an important relationship not only between EZH2 and markers of tumor cell proliferation but also with aggressive disease. These findings might be practically important and relevant because the polycomb group proteins have recently been suggested as candidates for targeted therapy.