Altered Expression of Survivin Variants S-2B and S-WT in Breast Cancer Is Related to Adipokine Expression

Abstract

Breast cancer (BCa) is one of the leading causes of death in women with these types of malignancies. Early detection is pivotal to improve prognosis and reduce mortality. Several proteins and genes have been proposed as biomarkers for cancer; however, further studies are required before a molecule is accepted as a definitive biomarker. This study was aimed at investigating the expression of survivin variants S-WT, S-2B, and S-ΔEx3, as well as adipokines LEP and ADIPOQ in breast cancer. Breast samples were obtained from patients with ( $n=27$ ) and without ( $n=20$ ) BCa, and relative gene expression was assessed by RT-qPCR. S-WT and S-2B showed a significant increase in BCa samples ( $p=0.005$ and $p=0.001$ , respectively) and in high-aggressiveness BCa ( $p=0.026$ and $p=0.037$ , respectively). Despite S-ΔEx3 expression remained globally unchanged, when dividing BCa samples according to the stage, this gene showed a significant tendency to increase towards more advanced stages, and the exact opposite effect was observed for LEP. Furthermore, LEP expression showed a negative correlation with S-2B ( $p=0.005$ ) and S-WT ( $p=0.011$ ), and in the same manner, ADIPOQ was negatively related with these two survivin variants ( $p=0.001$ and $p=0.005$ , respectively). Interestingly, S-ΔEx3 expression appears unaffected by LEP and ADIPOQ expressions. Our results highlight the importance of investigating specific variants of a given gene, as sequence variation may grant different correlation with other important structures and diseases.