The relationship between oestrogen receptor-alpha phosphorylation and the tumour microenvironment in patients with primary operable ductal breast cancer.

AIMS: Although the role of phosphorylation of oestrogen receptor (ER) at serines 118 (p-S118) and 167 (p-S167) has been studied, the relationship between p-S118, p-S167 and the tumour microenvironment in ER-positive primary operable ductal breast cancers have not been investigated. The aims of this study are to investigate (i) the relationship between p-S118/p-S167 and the tumour microenvironment, and (ii) the effect of p-S118/167 on survival and recurrence in ER-positive primary operable ductal breast cancers. METHODS AND RESULTS: Patients presenting at three Glasgow hospitals between 1995 and 1998 with invasive ductal ER-positive primary breast cancers were studied (n = 294). Immunohistochemical staining of p-S118 and p-S167 was performed and their association with clinicopathological characteristics, cancer-specific survival (CSS) and recurrence-free interval (RFI) were examined. In the whole cohort, tumour size (P < 0.05) and microvessel density (P < 0.05) were associated with high p-S118 while increased micovessel density (P < 0.05), apoptosis (P < 0.05), general inflammatory infiltrate measured using the Klintrup-Makinen score (P < 0.05) and macrophage infiltrate (P < 0.05) were found to be associated with high p-S167. Only high p-S167 was associated with shorter CSS (P < 0.005) and shorter RFI in the whole cohort (P = 0.001) and separately in the luminal A (P < 0.05) and B tumours (P < 0.05). CONCLUSIONS: This study showed that both p-S118 and p-S167 were associated with several microenvironmental factors, including increased microvessel density. In particular, p-S167 was associated with reduced RFI and CSS in the whole cohort and RFI in luminal A and B tumours and could possibly be employed to predict response to kinase inhibitors.

Androgen receptor phosphorylation at serine 81 and serine 213 in castrate-resistant prostate cancer.

BACKGROUND: Despite increases in diagnostics and effective treatments, over 300,000 men die from prostate cancer highlighting the need for specific and differentiating biomarkers. AR phosphorylation associates with castrate-resistance, with pARser213 promoting transcriptional activity. We hypothesise that combined pARser81 and pARser213 reduces survival and would benefit from dual-targeting androgen-dependent and Akt-driven disease. METHODS: Immunohistochemistry and immunofluorescence were performed on matched hormone-naive and castrate-resistant prostate cancer samples. TempO-Seq gene profiling was analysed using DESeq2 package. LNCaP-AI cells were stimulated with DHT or EGF. WST-1 assays were performed to determine effects of Enzalutamide and BKM120 on cell viability. RESULTS: Following the development of castrate-resistance, pARser81 expression reduced and pARser213 expression increased. Castrate-resistance pARser81 expression was not associated with survival but high pARser213 expression was associated with reduced survival from relapse. Combined high pARser81 and pARser213 was associated with reduced survival from relapse. pARser81 expression was induced by 10 nM DHT or 10 nM EGF and pARser213 expression was induced by treatment with 10 nM EGF in LNCaP-AI cells. Cell viability was reduced following treatment with 10 nM Enzalutamide and 10 nM BKM120. Eight genes were differentially expressed between hormone-naive and castrate-resistant tumours and twenty-five genes were differentially expressed between castrate-resistant tumours with high and low pARser213 expression. CONCLUSION: Combined pARser81 and pARser213 provides a novel prognostic biomarker for castrate-resistant disease and a potential predictive and therapeutic target for prostate cancer. Further studies will be required to investigate the combined effects of targeting AR and PI3K/AKT signalling.

MCL-1 is a prognostic indicator and drug target in breast cancer.

Analysis of publicly available genomic and gene expression data demonstrates that MCL1 expression is frequently elevated in breast cancer. Distinct from other pro-survival Bcl-2 family members, the short half-life of MCL-1 protein led us to investigate MCL-1 protein expression in a breast cancer tissue microarray and correlate this with clinical data. Here, we report associations between high MCL-1 and poor prognosis in specific subtypes of breast cancer including triple-negative breast cancer, an aggressive form that lacks targeted treatment options. Deletion of MCL-1 in the mammary epithelium of genetically engineered mice revealed an absolute requirement for MCL-1 in breast tumorigenesis. The clinical applicability of these findings was tested through a combination of approaches including knock-down or inhibition of MCL-1 to show triple-negative breast cancer cell line dependence on MCL-1 in vitro and in vivo. Our data demonstrate that high MCL-1 protein expression is associated with poor outcome in breast cancer and support the therapeutic targeting of MCL-1 in this disease.

Predictive Biomarkers for Endocrine Therapy: Retrospective Study in Tamoxifen and Exemestane Adjuvant Multinational (TEAM) Trial.

Background: Aromatase inhibitors improve disease-free survival compared with tamoxifen in postmenopausal women with hormone receptor-positive breast cancer. The Tamoxifen and Exemestane Adjuvant Multinational (TEAM) trial compared exemestane monotherapy with sequential therapy of tamoxifen followed by exemestane. The trial failed to show a statistically significant difference between treatment arms. A robust translational program was established to investigate predictive biomarkers. Methods: A tissue microarray was retrospectively constructed using a subset of patient tissues (n = 4631) from the TEAM trial (n = 9766). Immunohistochemistry was performed for biomarkers, classed into three groups: MAPK pathway, NF-kappa B pathway, and estrogen receptor (ER) phosphorylation. Expression was analyzed for association with relapse-free survival (RFS) at 2.5 and 10 years and treatment regimen using Kaplan-Meier curves and log-rank analysis. All statistical tests were two-sided. Results: In univariate analysis, ER167 (hazard ratio [HR] = 0.71, 95% confidence interval [CI] = 0.59 to 0.85, P < .001), IKKα (HR = 0.74, 95% CI = 0.60 to 0.92, P = .005), Raf-1338 (HR = 0.64, 95% CI = 0.52 to 0.80, P < .001), and p44/42 MAPK202/204 (HR = 0.77, 95% CI = 0.64 to 0.92, P = .004) were statistically significantly associated with improved RFS at 10 years in patients receiving sequential therapy. Associations were strengthened when IKKα, Raf-1338, and ER167 were combined into a cumulative prognostic score (HR = 0.64, 95% CI = 0.52 to 0.77, P < .001). Patients with an all negative IKKα, Raf-1338, and ER167 score favored exemestane monotherapy (odds ratio = 0.56, 95% CI = 0.35 to 0.90). In multivariable analysis, the IKKα, Raf-1338, and ER167 score (P = .001) was an independent prognostic factor for RFS at 10 years in patients receiving sequential therapy. Conclusions: The IKKα, Raf-1338, and ER167 score is an independent predictive biomarker for lower recurrence on sequential therapy. Negative expression may further offer predictive value for exemestane monotherapy.