Coexistence of HER2 over-expression and p53 protein accumulation is a strong prognostic molecular marker in breast cancer

INTRODUCTION: Many laboratories are currently evaluating the usefulness of determination of HER2, p53, and Ki67 proliferation indices using immunohistochemical techniques in cancer. Although the available studies suggest that these factors might indeed be helpful in making treatment decisions in cancer patients, their clinical usefulness is still controversial. METHODS: Expression of HER2, p53, and Ki67 was examined by immunohistochemistry in samples of breast tissue from 506 patients with invasive ductal carcinoma, obtained between 1981 and 1999 (median follow up period 82 months), and their significance for prognosis was analyzed. RESULTS: Of the 506 carcinoma tissue samples, 20.1%, 29.0%, and 53.6% were positive for HER2 over-expression, p53 protein accumulation, and Ki67 expression, respectively. Over-expression of HER2 significantly reduced disease free (P = 0.02) and overall survival (P = 0.005). Accumulation of p53 protein significantly decreased disease free (P = 0.01) and overall survival (P = 0.01). Patients with tumors that were positive for both HER2 and p53 relapsed and died within a significantly shorter period of time after surgery (P = 0.0001 and P < 0.0001, respectively). In multivariate analysis, patients with both HER2 and p53 positive tumors had considerably decreased overall survival (P = 0.04), as did patients with larger tumor size and positive lymph node status. CONCLUSION: The findings of the present study indicate that the coexistence of HER2 over-expression and p53 protein accumulation is a strong prognostic molecular marker in breast cancer

Quantitative determination, by real-time reverse transcription polymerase chain reaction, of aromatase mRNA in invasive ductal carcinoma of the breast

BACKGROUND: Estrogen is a mitogenic factor that is implicated in the genesis and progression of breast cancer via its binding to estrogen receptor (ER)-α. Synthesis of estrogen in situ is believed to be catalyzed mainly by aromatase. Previous studies comparing the relative contributions from tumor cells and stromal cells to local estrogen synthesis, as assessed by immunohistochemical analysis, were quite controversial and no consistent relationship was found between the presence of aromatase and any clinicopathologic factor. In addition, previous studies into aromatase gene expression and clinicopathologic factors are limited. METHODS: We assessed the level of expression of aromatase mRNA, using quantitative real-time RT-PCR, in 162 cases of invasive ductal carcinoma of the breast. Associations between aromatase expression and different clinicopathologic factors were sought. RESULTS: It was found that aromatase mRNA was expressed at significantly higher levels in patients older than 50 years, in those without axillary lymph node involvement, in those with tumor size less than 2 cm, and in ER-α positive tumors. However, no relationship was found between aromatase mRNA expression and any other clinicopathologic factor, including histologic grade and progesterone receptor status. Patients with high levels of expression of aromatase mRNA tended to have a better prognosis than did those patients with low expression. CONCLUSION: These findings imply that ER-α and aromatase may be coexpressed in endocrine responsive patients. They may also indicate that aromatase expression could be a marker of endocrine responsiveness, and it may have prognostic implications for breast cancer progression

Identification of targets of tumor suppressor microRNA-34a using a reporter library system

miRNAs play critical roles in various biological processes by targeting specific mRNAs. Current approaches to identifying miRNA targets are insufficient for elucidation of a miRNA regulatory network. Here, we created a cell-based screening system using a luciferase reporter library composed of 4,891 full-length cDNAs, each of which was integrated into the 3′ UTR of a luciferase gene. Using this reporter library system, we conducted a screening for targets of miR-34a, a tumor-suppressor miRNA. We identified both previously characterized and previously uncharacterized targets. miR-34a overexpression in MDA-MB-231 breast cancer cells repressed the expression of these previously unrecognized targets. Among these targets, GFRA3 is crucial for MDA-MB-231 cell growth, and its expression correlated with the overall survival of patients with breast cancer. Furthermore, GFRA3 was found to be directly regulated by miR-34a via its coding region. These data show that this system is useful for elucidating miRNA functions and networks

Frequently increased epidermal growth factor receptor (EGFR) copy numbers and decreased BRCA1 mRNA expression in Japanese triple-negative breast cancers

<p>Abstract</p> <p>Background</p> <p>Triple-negative breast cancer (estrogen receptor-, progesterone receptor-, and HER2-negative) (TNBC) is a high risk breast cancer that lacks specific therapy targeting these proteins.</p> <p>Methods</p> <p>We studied 969 consecutive Japanese patients diagnosed with invasive breast cancer from January 1981 to December 2003, and selected TNBCs based on the immunohistochemical data. Analyses of epidermal growth factor receptor (<it>EGFR</it>) gene mutations and amplification, and <it>BRCA</it>1 mRNA expression were performed on these samples using TaqMan PCR assays. The prognostic significance of TNBCs was also explored. Median follow-up was 8.3 years.</p> <p>Results</p> <p>A total of 110 (11.3%) patients had TNBCs in our series. Genotyping of the <it>EGFR </it>gene was performed to detect 14 known <it>EGFR </it>mutations, but none was identified. However, <it>EGFR </it>gene copy number was increased in 21% of TNBCs, while only 2% of ER- and PgR-positive, HER2-negative tumors showed slightly increased <it>EGFR </it>gene copy numbers. Thirty-one percent of TNBCs stained positive for EGFR protein by immunohistochemistry. <it>BRCA1 </it>mRNA expression was also decreased in TNBCs compared with controls. Triple negativity was significantly associated with grade 3 tumors, TP53 protein accumulation, and high Ki67 expression. TNBC patients had shorter disease-free survival than non-TNBC in node-negative breast cancers.</p> <p>Conclusion</p> <p>TNBCs have an aggressive clinical course, and <it>EGFR </it>and <it>BRCA1 </it>might be candidate therapeutic targets in this disease.</p

Identification of biomarkers in ductal carcinoma in situ of the breast with microinvasion

<p>Abstract</p> <p>Background</p> <p>Widespread use of mammography in breast cancer screening has led to the identification of increasing numbers of patients with ductal carcinoma <it>in situ </it>(DCIS). DCIS of the breast with an area of focal invasion 1 mm or less in diameter is defined as DCIS with microinvasion, DCIS-Mi. Identification of biological differences between DCIS and DCIS-Mi may aid in understanding of the nature and causes of the progression of DCIS to invasiveness.</p> <p>Methods</p> <p>In this study, using resected breast cancer tissues, we compared pure DCIS (52 cases) and DCIS-Mi (28 cases) with regard to pathological findings of intraductal lesions, biological factors, apoptosis-related protein expression, and proliferative capacity through the use of immunohistochemistry and the TdT-mediated dUTP-biotin nick end labeling (TUNEL) method.</p> <p>Results</p> <p>There were no differences in biological factors between DCIS and DCIS-Mi, with respect to levels of estrogen receptor, progesterone receptor, and human epidermal growth factor receptor type 2. The frequency of necrosis and positive expression ratio of survivin and Bax were significantly higher in DCIS-Mi than in DCIS. In addition, apoptotic index, Ki-67 index, and positive Bcl-2 immunolabeling tended to be higher in DCIS-Mi than in DCIS. Multivariate analysis revealed that the presence of necrosis and positive survivin expression were independent factors associated with invasion.</p> <p>Conclusion</p> <p>Compared with DCIS, DCIS-Mi is characterized by a slightly elevated cell proliferation capacity and enhanced apoptosis within the intraductal lesion, both of which are thought to promote the formation of cell necrotic foci. Furthermore, the differential expression of survivin may serve in deciding the response to therapy and may have some prognostic significance.</p