SIRT5 as a biomarker for response to anthracycline-taxane-based neoadjuvant chemotherapy in triple-negative breast cancer

Neoadjuvant chemotherapy (NAC) is of great importance for patients with triple-negative breast cancer (TNBC) and the achievement of pathological complete response (pCR) to NAC in TNBC patients indicates survival benefits. However, the identification of reliable predictive biomarkers of pCR to NAC in TNBC patients remains an urgent and largely unattended medical issue. In the present study, we evaluated the differentially expressed genes (DEGs) between pCR and non-pCR patients after doxorubicin/cyclophosphamide therapy, followed by paclitaxel pre-operative treatment in 64 TNBC patients recorded in the GSE41998 dataset of Gene Expression Omnibus and identified 118 DEGs. Subsequently, we selected five core genes that were closely associated with the pCR of TNBC patients by using a genetic algorithm-support vector machine-based method. Sirtuin 5 (SIRT5) was one of the five core genes and patients who achieved pCR expressed higher levels of SIRT5. Thus, we speculated that SIRT5 may be a potential predictive marker of the response to anthracycline-taxane-based chemotherapy. Oncomine analysis revealed that the expression levels of SIRT5 were higher in epirubicin/cyclophosphamide-docetaxel responders compared with non-responders. Furthermore, Gene Ontology analysis indicated that SIRT5 may affect the response to anthracycline-taxane-based chemotherapy by regulating the Rho pathway. It was also observed that SIRT5 was upregulated in TNBC and breast cancer with BRCA1 mutation subtypes. High SIRT5 expression was also associated with poor clinical outcomes of breast cancer patients. In conclusion, the present study revealed SIRT5 as a biomarker for response to anthracycline-taxane-based NAC in patients with TNBC and identified a series of novel biological functions of SIRT5 in breast cancer.