SRC3 Phosphorylation at Serine 543 Is a Positive Independent Prognostic Factor in ER-Positive Breast Cancer.

PURPOSE: The steroid receptor coactivator SRC3 is essential for the transcriptional activity of estrogen receptor α (ERα). SRC3 is sufficient to cause mammary tumorigenesis, and has also been implicated in endocrine resistance. SRC3 is posttranslationally modified by phosphorylation, but these events have not been investigated with regard to functionality or disease association. Here, we investigate the spatial selectivity of SRC3-pS543/DNA binding over the human genome and its expression in primary human breast cancer in relation with outcome. EXPERIMENTAL DESIGN: Chromatin immunoprecipitation, coupled with sequencing, was used to determine the chromatin binding patterns of SRC3-pS543 in the breast cancer cell line MCF7 and two untreated primary breast cancers. IHC was used to assess the expression of SRC3 and SRC3-pS543 in 1,650 primary breast cancers. The relationship between the expression of SRC3 and SRC3-pS543, disease-free survival (DFS), and breast cancer specific survival (BCSS) was assessed. RESULTS: Although total SRC3 is selectively found at enhancer regions, SRC3-pS543 is recruited to promoters of ERα responsive genes, both in the MCF7 cell line and primary breast tumor specimens. SRC3-pS543 was associated with both improved DFS (P = 0.003) and BCSS (P = 0.001) in tamoxifen untreated high-risk patients, such a correlation was not seen in tamoxifen-treated cases, the interaction was statistically significant (P = 0.001). Multivariate analysis showed SRC3-pS543 to be an independent prognostic factor. CONCLUSIONS: Phosphorylation of SRC3 at S543 affects its genomic interactions on a genome-wide level, where SRC3-pS543 is selectively recruited to promoters of ERα-responsive genes. SRC3-pS543 is a prognostic marker, and a predictive marker of response to endocrine therapy.

Neoadjuvant chemotherapy and trastuzumab versus neoadjuvant chemotherapy followed by post-operative trastuzumab for patients with HER2-positive breast cancer.

Neoadjuvant chemotherapy plus trastuzumab (NCT) increases the rate of pathological complete response (pCR) and event-free survival (EFS) compared to neoadjuvant chemotherapy (NC) alone in women with HER2 positive breast cancer (BC). pCR in this setting is associated with improved EFS. Whether NCT preferentially improves EFS in comparison to NC followed by adjuvant trastuzumab initiated postoperatively (NCAT) has not been addressed. Using clinical data from women with HER2 positive BC treated at 7 European institutions between 2007 and 2010 we sought to investigate the impact on breast cancer outcomes of concomitant (NCT) versus sequential (NCAT) treatment in HER2 positive early BC. The unadjusted hazard ratio (HR) for event free survival with NCT compared with NCAT was 0.63 (95% CI 0.37-1.08; p = 0.091). Multivariable analysis revealed that treatment group, tumour size and ER status were significantly associated with EFS from diagnosis. In the whole group NCT was associated with a reduced risk of an event relative to NCAT, an effect that was confined to ER negative (HR: 0.25; 95% CI, 0.10-0.62; p = 0.003) as opposed to ER positive tumours (HR: 1.07; 95% CI, 0.46-2.52; p = 0.869). HER2 positive/ER negative BC treated with NC gain greatest survival benefit when trastuzumab is administered in both the neoadjuvant and adjuvant period rather than in the adjuvant period alone. These data support the early introduction of targeted combination therapy in HER2 positive/ER negative BC.

Expression of selected proteins in breast cancer brain metastases.

The aim of the study was to assess the immunohistochemical (IHC) profiles of SRC3, Pax2, ER, PgR, Her2, EGFR, CK5/6, and Ki67 proteins in breast-cancer brain metastasis. The study utilized tumor samples from 30 metastatic patients and calculated correlations between all IHC variables. In fourteen cases, primary breast cancers paired with secondary deposits were analyzed. We evaluated the association between IHC status in the primary and secondary deposits, grade, and histotype of the tumors. The examination of the metastatic deposits in all 30 patients resulted in positive detection in the following cases: SRC3 in 20 cases (66.6%), Pax2 in 22 (73.3%), ER in 22 (73.3%), PgR in 25 (83.3%), Her2 in 10 (33.3%), EGFR in 12 (40%), CK5/6 in 7 (23.3%), and Ki67 in 23 (76.6%). Grade 2 was found in 13.3% of all patients, and grade 3 in 86.7%. SRC3 and Pax2 were positive in both G2 and G3. Invasive lobular carcinoma and invasive ductal carcinoma were diagnosed in 23.3% and 76.7% of cases, respectively. There were no differences between the IHC expression of the studied proteins in either grading or histotype of the tumors. In the IHC profiles, which included SRC3, Pax2, ER, PgR, Her2, CK5/6, Ki67, and EGFR, we found no statistically significant differences between the primary cancer and the brain metastasis. In our study of metastatic breast carcinoma deposits, there was no correlation between SRC3, Pax2 status and histotype, and tumor grade. The IHC status of the paired primary and metastatic deposits did not differ in a statistically significant manner.

Differential oestrogen receptor binding is associated with clinical outcome in breast cancer.

Oestrogen receptor-α (ER) is the defining and driving transcription factor in the majority of breast cancers and its target genes dictate cell growth and endocrine response, yet genomic understanding of ER function has been restricted to model systems. Here we map genome-wide ER-binding events, by chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq), in primary breast cancers from patients with different clinical outcomes and in distant ER-positive metastases. We find that drug-resistant cancers still recruit ER to the chromatin, but that ER binding is a dynamic process, with the acquisition of unique ER-binding regions in tumours from patients that are likely to relapse. The acquired ER regulatory regions associated with poor clinical outcome observed in primary tumours reveal gene signatures that predict clinical outcome in ER-positive disease exclusively. We find that the differential ER-binding programme observed in tumours from patients with poor outcome is not due to the selection of a rare subpopulation of cells, but is due to the FOXA1-mediated reprogramming of ER binding on a rapid timescale. The parallel redistribution of ER and FOXA1 binding events in drug-resistant cellular contexts is supported by histological co-expression of ER and FOXA1 in metastatic samples. By establishing transcription-factor mapping in primary tumour material, we show that there is plasticity in ER-binding capacity, with distinct combinations of cis-regulatory elements linked with the different clinical outcomes.

Human epidermal growth factor receptor 2-positive breast cancer relapsing post-adjuvant trastuzumab: pattern of recurrence, treatment and outcome.

BACKGROUND: The purpose of this study is to evaluate the response to and benefit of first-line metastatic treatment (including re-exposure to trastuzumab) for patients relapsing after exposure to adjuvant trastuzumab (AT). PATIENTS AND METHODS: All HER2-positive breast cancer cases relapsing after exposure to AT at our institutions were identified. Clinico-pathologic details, pattern of relapse, and treatment in the metastatic setting were documented. Response to treatment and outcome were assessed. RESULTS: Twenty-nine relapses were recorded. The median time to relapse was 18.4 months from diagnosis, and 8.7 months from AT initiation. At a median time of observation of 9.9 months, 18 patients had progressed on first-line therapy. The median time-to-progression (TTP) was 8.6 months. Fifteen patients received trastuzumab as first-line treatment, with no statistical difference in TTP between this group and those not re-exposed to trastuzumab. TTP was not statistically different between those relapsing on or after AT. Overall survival was longer for those who relapsed after completion of 1 year of AT as well as those who received further trastuzumab at relapse; however, this did not reach statistical significance. CONCLUSION: Overall survival was longer in patients who relapse after completion of AT and who received further trastuzumab at progression.

Management and outcome of HER2-positive early breast cancer treated with or without trastuzumab in the adjuvant trastuzumab era.

BACKGROUND: Adjuvant trastuzumab (AT) is known to significantly improve survival of women with HER2(+) early breast cancer. This study explores the use and nonuse of AT in early breast cancer, as well as the efficacy in a neoadjuvant and adjuvant population, within a routine clinical setting. PATIENTS AND METHODS: Histopathology reports of invasive breast cancer resected at Imperial College Healthcare NHS Trust (ICHT) between January 2006 and December 2008 were reviewed. HER2(+) patients were identified and their case notes reviewed. In addition, patients who received AT at our center but underwent surgery elsewhere were included in the efficacy and safety analyses. RESULTS: The local HER2(+) rate was 13.1%, with 54.5% of these patients receiving AT. A total of 128 patients received AT (85 local and 43 referrals from elsewhere). Neoadjuvant chemotherapy (CT) followed by postoperative AT was associated with a significantly increased risk of recurrence compared with adjuvant CT and then AT (hazard ratio [HR] 18.6 [95% CI, 1.8-152.2]; P = .013). The proportion of patients who were disease free at 3 years from primary therapy was 96.4% (95% CI, 89.8%-100%) for adjuvant therapy, compared with 72.0% (95% CI, 56.5%-91.6%) for neoadjuvant therapy. AT was omitted in 49 HER2(+) patients; the main reason for AT omission was clinical judgment that the breast cancer was low risk. Patients treated with AT had a significantly decreased risk of recurrence (HR 0.27 [95% CI, 0.08-0.97]; P = .04) compared with the untreated patients. The majority of untreated relapses were in patients in whom there was an original intent to use AT. The proportion alive at 3 years for adjuvant CT, neoadjuvant CT, and untreated AT was 100%, 74.5%, and 92.7% respectively. CONCLUSION: The overall efficacy and safety of AT in our routine clinical setting is comparable to the large randomized trials. HER2(+) patients who underwent neoadjuvant CT had a significantly increased risk of disease recurrence compared with patients treated with adjuvant CT followed by trastuzumab. Untreated patients had an increased risk of recurrence.

The role of SRC-3 in human breast cancer.

Members of the nuclear receptor superfamily are ligand-regulated transcription factors involved in the control of a broad range of normal physiological and disease processes. The estrogen receptor alpha (ERalpha) is a member of the steriod receptor family, which is part of the nuclear receptor superfamily. ERalpha it is important for many biological processes and plays a key role in the pathogenesis of breast cancer. Gene regulation by ERalpha requires the recruitment of a multitude of transcriptional co-regulators to the promoters of estrogen-responsive genes. There is evidence in support of the involvement of these co-regulators in breast cancer progression. We review the role of steroid receptor co-activator-3 (SRC-3), which is frequently amplified in breast cancer, and its role in breast cancer risk, outcome and response to endocrine therapy in patients with breast cancer.

FoxM1 is a downstream target and marker of HER2 overexpression in breast cancer.

The tyrosine kinase receptor, HER2 is a crucial prognostic marker and therapeutic target for breast cancer; however, the downstream targets and biological effectors of HER2 remain unclear. We investigated the relationship between HER2 and the transcription factor FoxM1 in breast cancer. HER2 and FoxM1 expression levels were compared in breast carcinoma cell lines, paraffin-embedded breast cancer patient samples and at the mRNA level in purified breast epithelial cells. To further examine the relationship between HER2 and FoxM1 expression, we either overexpressed or siRNA-mediated depleted endogenous HER2 in breast cancer cell lines. Additionally, a mammary epithelium-targeted HER2 (neu) transgenic mouse model was also used to assess the effect of HER2 on FoxM1 levels. Furthermore, the effect of the HER2-tyrosine kinase inhibitor lapatinib on FoxM1 in HER2 positive breast cancer cells was investigated. HER2 protein levels directly correlated with FoxM1 expression in both breast carcinoma cell lines and paraffin-embedded breast cancer patient samples. Moreover, in purified breast epithelial cells, overexpression of HER2 was associated with high levels of FoxM1 mRNA, suggesting that the upregulation of FoxM1 expression is at least partially mediated transcriptionally. Furthermore, overexpression or ablation of endogenous HER2 resulted in parallel changes in FoxM1 expression. Critically, mammary epithelium-targeted HER2 mouse tumours also resulted in increased FoxM1 expression, suggesting that HER2 directed FoxM1 expression occurs in vivo and may be a critical downstream effector of HER2-targeting therapies. Indeed, treatment of breast cancer cells with lapatinib reduced FoxM1 expression at protein, mRNA and gene promoter levels. Moreover, analysis of normal and breast cancer patient samples revealed that elevated FoxM1 expression at protein and mRNA levels correlated with breast cancer development, but not significantly with cancer progression and survival. Our results indicate that the HER2 receptor regulates the expression of the FoxM1 transcription factor, which has a role in breast cancer development.

Guided tissue regeneration, barrier membranes and reconstruction of the cleft maxillary alveolus.

The use of barrier membranes for bone regeneration is especially beneficial in the case of severely affected soft tissue. One useful indication may be the formation of an effective shell for bone grafts in maxilla cleft defect reconstruction. When selecting a proper material for clinical use, one must consider the safety record, the resorption time and route of elimination, the time of the maintained barrier function, the necessary time of mechanical strength, and costs. Two resorbable collagen membranes, one of single-layer and one of double-layer material, were tested in vitro and in vivo. The tested single-layer membrane is less expensive, but it is also less handling than the double-layer membrane. In vitro, samples were incubated in simulated surgical wound. A complete unambiguous picture of disintegration was not proved histologically in either material in six investigation terms (1-6 weeks). In vivo the effect of the assessed membranes was verified on a group of patients (N = 45) with a cleft. Materials were applied in the reconstruction of the alveolar defect by cancellous bone grafts. The influence on the course of healing was not stated as statistically significant. However, with respect to the costs of double layer membrane, this material was used in the most severe cases.