Secreted Protein Acidic and Rich in Cysteine ( SPARC) Polymorphisms in Response to Neoadjuvant Chemotherapy in HER2-Negative Breast Cancer Patients

Secreted protein acidic and rich in cysteine (SPARC) expression has been proposed as a prognostic and predictive biomarker for some cancer types, but knowledge about the predictive value of polymorphisms in the context of neoadjuvant therapy for breast cancer (BC) is lacking. In 132 HER2-negative BC patients treated with neoadjuvant chemotherapy, we determined polymorphisms in the gene and analyzed their association with outcome. We also determined SPARC protein expression in tumor tissue. rs19789707 was significantly associated with response to treatment according to the Miller and Payne system in the breast (multivariate: odds ratio (OR), 3.81; = 0.028). This association was significant in the subgroup of patients with luminal tumors (univariate: = 0.047). Regarding survival, two variants showed significant associations with event-free survival: the rs19789707 variant in the subgroup of luminal A tumors (univariate: = 0.006), and the rs4958487 variant in the subgroup of luminal B tumors (univariate: = 0.022). In addition, rs4958487, rs10065756, and rs12153644 were significantly correlated with SPARC protein expression. Our findings suggest that polymorphisms could be good predictors of treatment response and survival in BC patients treated with neoadjuvant chemotherapy, especially those with luminal tumors.