GPER functions as a tumor suppressor in MCF-7 and SK-BR-3 breast cancer cells.

PURPOSE: The orphan, membrane-bound estrogen receptor (GPER) is expressed at high levels in a large fraction of breast cancer patients, and its expression is favorable for patients' survival. We investigated the role of GPER as a potential tumor suppressor in MCF-7 and SK-BR-3 breast cancer cells. METHODS: The effect of GPER agonist G-1 in cell culture was used to determine whether GPER inhibit cell growth. The methylation status of GPER promoter was investigated by methylation-specific PCR. RESULTS: GPER-specific agonist G-1 inhibited breast cancer cell proliferation in concentration-dependent manner via induction of the cell cycle arrest in M-phase, enhanced phosphorylation of histone 3 and cell apoptosis. Analysis of the methylation status of the GPER promoter in MCF-7 and SK-BR-3 cells revealed that GPER expression is regulated by epigenetic mechanisms and GPER expression is inactivated by promoter methylation. Overall, our results are consistent with our recent findings in triple-negative breast cancer cells, and the cell surface expression of GPER makes it an excellent potential therapeutic target for non-triple-negative breast cancer.

Response and prognosis after neoadjuvant chemotherapy in 1,051 patients with infiltrating lobular breast carcinoma.

Invasive lobular carcinomas (ILC) show better clinical behaviour compared with other histological types, but significantly lower pathological complete response (pCR) rates after neoadjuvant chemotherapy (NACT). We investigated whether factors influencing pCR rate in ILC after NACT can be identified and whether clinical outcome is different. 9,020 breast cancer patients from nine German neoadjuvant trials with known histological type were pooled. 11.7 % of tumours were ILC. Endpoints were: pCR rate, surgery type and survival. ILC was associated with older age, larger tumour size, lymph node negativity, lower grade and positive hormone-receptor-status (HR). Patients with ILC achieved a significantly lower pCR rate compared with non-ILC patients (6.2 vs. 17.4 %, P < 0.001). The pCR rate was 4.2 % in ILC/HR+/G1-2, 7.0 % in ILC with either HR- or G3, and 17.8 % in ILC/HR-/G3. Mastectomy rate was higher in ILC compared with non-ILC patients irrespective of response to NACT (pCR: 27.4 vs. 16.6 %, P = 0.037 and non-pCR: 41.8 % vs. 31.5 %, P < 0.0001). Age and HR independently predicted pCR in ILC. In ILC patients, pCR did not predict distant disease free (DDFS) and loco-regional disease free survival (LRFS), but overall survival (OS). Non-pCR patients with ILC had significantly better DDFS (P = 0.018), LRFS (P < 0.0001) and OS (P = 0.044) compared with non-ILC patients. Patients with ILC had a low chance of obtaining a pCR and this is not well correlated with further outcome. The mastectomy rate was considerably high in ILC patients even after obtaining a pCR. We, therefore, suggest to offer NACT mainly to ILC patients with HR-negative tumours.

Definition and impact of pathologic complete response on prognosis after neoadjuvant chemotherapy in various intrinsic breast cancer subtypes.

PURPOSE: The exact definition of pathologic complete response (pCR) and its prognostic impact on survival in intrinsic breast cancer subtypes is uncertain. METHODS: Tumor response at surgery and its association with long-term outcome of 6,377 patients with primary breast cancer receiving neoadjuvant anthracycline-taxane-based chemotherapy in seven randomized trials were analyzed. RESULTS: Disease-free survival (DFS) was significantly superior in patients with no invasive and no in situ residuals in breast or nodes (n = 955) compared with patients with residual ductal carcinoma in situ only (n = 309), no invasive residuals in breast but involved nodes (n = 186), only focal-invasive disease in the breast (n = 478), and gross invasive residual disease (n = 4,449; P < .001). Hazard ratios for DFS comparing patients with or without pCR were lowest when defined as no invasive and no in situ residuals (0.446) and increased monotonously when in situ residuals (0.523), no invasive breast residuals but involved nodes (0.623), and focal-invasive disease (0.727) were included in the definition. pCR was associated with improved DFS in luminal B/human epidermal growth factor receptor 2 (HER2) -negative (P = .005), HER2-positive/nonluminal (P < .001), and triple-negative (P < .001) tumors but not in luminal A (P = .39) or luminal B/HER2-positive (P = .45) breast cancer. pCR in HER2-positive (nonluminal) and triple-negative tumors was associated with excellent prognosis. CONCLUSION: pCR defined as no invasive and no in situ residuals in breast and nodes can best discriminate between patients with favorable and unfavorable outcomes. Patients with noninvasive or focal-invasive residues or involved lymph nodes should not be considered as having achieved pCR. pCR is a suitable surrogate end point for patients with luminal B/HER2-negative, HER2-positive (nonluminal), and triple-negative disease but not for those with luminal B/HER2-positive or luminal A tumors.

Role of GPR30 in endometrial pathology after tamoxifen for breast cancer.

OBJECTIVE: This study was undertaken to evaluate the potential role of G-protein-coupled estrogen receptor in endometrial pathology associated with tamoxifen treatment of breast cancer patients. STUDY DESIGN: We investigated whether G-protein-coupled estrogen receptor plays a role in mediating proliferating effect of tamoxifen in endometrial carcinoma cells. These results were compared with the G-protein-coupled estrogen receptor expression pattern in endometrial tissue from a cohort of 95 breast cancer patients, who received tamoxifen or another adjuvant therapy. RESULTS: In vitro tamoxifen significantly stimulated the mitogen-activated protein kinase phosphorylation and cell proliferation of endometrial cell lines via G-protein-coupled estrogen receptor. In vivo, there was a significant correlation between G-protein-coupled estrogen receptor expression and the tamoxifen-induced endometrial pathology (P = .006). Moreover, G-protein-coupled estrogen receptor positivity was predictive of an earlier development of symptoms, such as bleeding or suspect endometrial thickness, induced by tamoxifen therapy (P = .019). CONCLUSION: G-protein-coupled estrogen receptor plays an important role in tamoxifen-induced endometrial abnormalities.

APC promoter hypermethylation is an early event in endometrial tumorigenesis.

The aim of the current study was to investigate the role of promoter methylation of adenomatous polyposis coli (APC) and epithelial cadherin (E-cadherin) genes in endometrial tumorigenesis. The methylation status of both genes was investigated in 43 cases of normal endometrium, 21 simple hyperplasia, 17 atypical hyperplasia, and 86 endometrial carcinoma (EC). Additionally, the methylation pattern of both genes was analyzed in 24 primary ECs and their corresponding metastases. DNA methylation of the APC gene increased from atypical hyperplasia (23.5%) to endometrial carcinoma, reaching its highest level of 77.4% in early stage cancer (FIGO I and II) and decreasing stepwise to 24.2% in advanced stage carcinomas (FIGO III and IV). No methylation of APC was found in normal endometrium or simple hyperplasia. Methylation of E-cadherin was found only in EC (22.1%). The mean age of the patients with aberrant APC methylation was 68.8 years and was significantly higher compared to the mean age (60.9 years) of the patients without methylation of APC promoter (P = 0.02). APC promoter methylation significantly correlated with decreased protein expression of APC (P = 0.039), with increased expression of the Ki-67 proliferative marker (P = 0.006) and decreased metastatic potential (P = 0.002). There was no correlation between APC and E-cadherin methylation patterns and the other clinicopathologic features, nor with patient outcome. Our results suggest that hypermethylation of APC promoter region is an early event in endometrial tumorigenesis.

P16 alterations increase the metastatic potential of endometrial carcinoma.

OBJECTIVE: The aim of this study was to investigate the role of p16 in tumorigenesis of endometrial carcinoma (EC). METHODS: Expression of p16 protein was analyzed using immunohistochemistry. The methylation status of p16 promoter region was determined by methylation-specific PCR. Deletion analysis of the p16 gene was performed by PCR-analyses. RESULTS: Aberrant protein expression of p16 was observed in 18 of 46 (39.2%) ECs and correlated significantly with p16 alterations, including gene deletions in 26 of 46 (56.5%) ECs and promoter hypermethylation in 8 of 46 (17.4%) ECs (p<0.001). A significant increase in the frequency of p16 alterations from early stage (I-II) to advanced stage (III-IV) ECs was observed (p=0.002). There was no significant correlation between p16 protein expression and the clinico-pathological features of EC. The development of metastases correlated significantly with the frequency of p16 alterations: p16 alterations were detected in 14 of 15 (93.3%) PTs with metastases and in only 18 of 31 (58.1%) PTs without metastases (p=0.018). The genetic comparison of 15 primary ECs and their paired metastases revealed that in most of the cases the deleted region of p16 gene remains the same or becomes larger during the progression from primary tumor to its corresponding metastases. CONCLUSION: Our results suggest that p16 alterations and particularly p16 gene deletions in ECs are associated with increased incidence of metastases.

Clinical response after two cycles compared to HER2, Ki-67, p53, and bcl-2 in independently predicting a pathological complete response after preoperative chemotherapy in patients with operable carcinoma of the breast.

INTRODUCTION: To investigate the predictive value of clinical and biological markers for a pathological complete remission after a preoperative dose-dense regimen of doxorubicin and docetaxel, with or without tamoxifen, in primary operable breast cancer. METHODS: Patients with a histologically confirmed diagnosis of previously untreated, operable, and measurable primary breast cancer (tumour (T), nodes (N) and metastases (M) score: T2-3(> or = 3 cm) N0-2 M0) were treated in a prospectively randomised trial with four cycles of dose-dense (bi-weekly) doxorubicin and docetaxel (ddAT) chemotherapy, with or without tamoxifen, prior to surgery. Clinical and pathological parameters (menopausal status, clinical tumour size and nodal status, grade, and clinical response after two cycles) and a panel of biomarkers (oestrogen and progesterone receptors, Ki-67, human epidermal growth factor receptor 2 (HER2), p53, bcl-2, all detected by immunohistochemistry) were correlated with the detection of a pathological complete response (pCR). RESULTS: A pCR was observed in 9.7% in 248 patients randomised in the study and in 8.6% in the subset of 196 patients with available tumour tissue. Clinically negative axillary lymph nodes, poor tumour differentiation, negative oestrogen receptor status, negative progesterone receptor status, and loss of bcl-2 were significantly predictive for a pCR in a univariate logistic regression model, whereas in a multivariate analysis only the clinical nodal status and hormonal receptor status provided significantly independent information. Backward stepwise logistic regression revealed a response after two cycles, with hormone receptor status and lymph-node status as significant predictors. Patients with a low percentage of cells stained positive for Ki-67 showed a better response when treated with tamoxifen, whereas patients with a high percentage of Ki-67 positive cells did not have an additional benefit when treated with tamoxifen. Tumours overexpressing HER2 showed a similar response to that in HER2-negative patients when treated without tamoxifen, but when HER2-positive tumours were treated with tamoxifen, no pCR was observed. CONCLUSION: Reliable prediction of a pathological complete response after preoperative chemotherapy is not possible with clinical and biological factors routinely determined before start of treatment. The response after two cycles of chemotherapy is a strong but dependent predictor. The only independent factor in this subset of patients was bcl-2.

Doxorubicin with cyclophosphamide followed by docetaxel every 21 days compared with doxorubicin and docetaxel every 14 days as preoperative treatment in operable breast cancer: the GEPARDUO study of the German Breast Group.

PURPOSE: Dose-dense and sequential administration of cytotoxic drugs are current approaches to improve outcomes in patients with early-stage breast cancer. METHODS: This phase III study investigated 913 women with untreated operable breast cancer (T2-3, N0-2, M0) randomly assigned to receive either doxorubicin 50 mg/m2 plus docetaxel 75 mg/m2 every 14 days for four cycles with filgrastim support (ADOC), or doxorubicin 60 mg/m2 plus cyclophosphamide 600 mg/m2 every 21 days followed by docetaxel 100 mg/m2 every 21 days for four cycles each (AC-DOC). The primary end point was the incidence of pathologic complete (invasive and noninvasive) response (pCR) in the breast and axillary nodes. Secondary end points were predictors for pCR, clinical response, rate of breast conservation, and safety. RESULTS: A pCR was achieved in 94 patients (10.6%), but the likelihood was significantly greater with AC-DOC (14.3%; n = 63) than with ADOC (7.0%; n = 31) (odds ratio, 2.22; 90% CI, 1.52 to 3.24; P < .001). Independent predictors of attaining a pCR included the use of sequential therapy, high tumor grade, and negative hormone receptor status. The response rates detected by palpation and by imaging were significantly higher with AC-DOC (85.0% and 78.6%, respectively) than with ADOC (75.2% and 68.6%, respectively; both P values < .001). The rate of breast-conserving surgery was 63.4% for AC-DOC and 58.1% for ADOC (P = .05). Predominant grade 3/4 toxicities were leucopenia (AC-DOC, 74.2%; ADOC, 53.7%) and neutropenia (AC-DOC, 66.4%; ADOC, 44.7%) but were infrequently associated with fever (AC-DOC, 4.6%; ADOC, 3.1%). CONCLUSION: Sequential AC-DOC is more effective at inducing pCR than dose-dense ADOC as preoperative treatment for patients with operable breast cancer.