The Evaluation of Cancer Testis Gene PIWIL2 Expression Levels as a New Prognostic Biomarker for Breast Cancer.

Abstract

Breast cancer is the most prevalent cancer and foremost reason of death resulting from malignancy among women worldwide. In recent years, it has been reported that a group of genes named cancer testis genes (CTg) express in adult immune privileged sites and some embryonic tissues. Likewise, it has been demonstrated that CTgs express aberrantly in various tumors and play essential roles in both initiation and development of cancers. In this study, PIWIL2, one member of CTgs, which has an indispensable role in spermatogenesis and tumorigenesis, was examined as an efficient prognostic and diagnostic biomarker in breast cancer. It is worth mentioning that the expression study of PIWIL2 by qPCR on breast cancer samples was performed for the first time, since this approach is much more sensitive than western blot, RT-PCR, and immunohistochemistry. To investigate the expression status of PIWIL2 in breast cancer, 72 fresh cancerous and normal adjacent specimens from 44 patients who had undergone surgery in Shahid Faghihi Hospital were used. None of the patients had received chemotherapy. The relationships between the PIWIL2 status and the clinicopathological parameters were ultimately determined. It was ascertained that the expression rates of PIWIL2 in cancerous breast tissues were related to patients' age, tumor stage, tumor size, tumor grade, and lymph node involvement (p < 0.05). The PIWIL2 gene could be considered as an efficient prognostic biomarker in breast cancer.