MicroRNAs Contribute to Breast Cancer Invasiveness

HOXB5 promotes the progression of breast cancer through wnt/beta-catenin pathway

OBJECTIVE

The present study was designed to explore the function of HOXB5 in breast cancer and related signaling pathway.

METHODS

Breast cancer tissues and non-cancerous tissues were collected from 82 cases who were pathologically diagnosed with breast cancer. The mRNA level of HOXB5 was detected via quantitative real-time polymerase chain reaction (qRT-PCR). Chi-square test was adopted to analyze the association of HOXB5 with clinical features. The viability, migration and invasion of breast cancer cells were detected through MTT and Transwell assays, respectively. Protein analysis was performed adopting western blot analysis.

RESULTS

HOXB5 expression was increased in breast cancer tissues and cells, and showed positive correlation with tumor size (P = 0.028), TNM stage (P = 0.048), and lymph node metastasis (P = 0.002). Losing HOXB5 expression suppressed clone formation, proliferation, migration and invasion of breast cancer cells. The knockdown of HOXB5 significantly inactivated wnt/β-catenin pathway. Furthermore, wnt/β-catenin pathway had the potential to neutralize the oncogenic function of HOXB5 in breast cancer.

CONCLUSION

HOXB5 may be involved in the invasive progression of breast cancer. The function of HOXB5 in breast cancer was mediated by wnt/β-catenin pathway.

Low Expression of miR-20a-5p Predicts Benefit to Bevacizumab in Metastatic Breast Cancer Patients Treated within the TANIA Phase III Trial

Background: In metastatic breast cancer (MBC) patients, no biomarker predicting benefit to a bevacizumab-containing therapy has been established yet. MicroRNAs (miRNAs) are involved in angiogenesis and treatment resistance and therefore could be of predictive value. Methods: Profiling of 754 miRNAs was performed in tumor samples of 58 MBC patients treated with a bevacizumab-containing first-line regimen (learning set). Based on progression-free survival (PFS), patients were divided into responders (R) and non-responders (NR). Differentially expressed miRNAs between R and NR were analyzed in a cohort of 57 patients treated with first-line chemotherapy without bevacizumab (control set), to exclude miRNAs providing prognostic information. MiRNA candidates significantly associated with PFS in multivariate analysis were further validated in tumor samples of 203 patients treated within the phase III trial TANIA randomizing between chemotherapy either alone or with bevacizumab after progression on first-line bevacizumab. Results: Low expression of miR-20a-5p (multivariate p = 0.035) and miR-21-5p (multivariate p = 0.004) were significantly associated with longer PFS in the learning set, but not in the control set. In samples from the TANIA trial, low expression of miR-20a-5p was also significantly associated with longer PFS (hazard ration (HR) 0.60; 95%-CI 0.37–0.89; p = 0.012) and longer overall survival (OS; HR 0.54; 95%-CI 0.32–0.83; p = 0.007) in the bevacizumab arm but not in the chemotherapy-only arm (PFS: HR 0.73, p = 0.119; OS: HR 1.01; p = 0.964). For miR-21-5p no significant association with PFS or OS in both treatment arms was observed. Conclusion: MiR-20a-5p expression in breast cancer tissue was predictive for a greater benefit from bevacizumab-containing therapy in two independent cohorts.

Genetics and Genomics of Breast Cancer: update and translational perspectives

In the recent years the rapid scientific innovation in the evaluation of the individual's genome have allowed the identification of variants associated with the onset, treatment and prognosis of various pathologies including cancer, and with a potential impact in the assessment of therapy responses. Despite the analysis and interpretation of genomic information is considered incomplete, in many cases the identification of specific genomic profile has allowed the stratification of subgroups of patients characterized by a better response to drug therapies. Individual genome analysis has changed profoundly the diagnostic and therapeutic approach of breast cancer in the last 15 years by identifying selective molecular lesions that drive the development of neoplasms, showing that each tumor has its own genomic signature, with some specific features and some features common to several sub-types. Several personalized therapies have been (and still are being) developed showing a remarkable efficacy in the treatment of breast cancer.