Mismatch Repair System Gene Expression in FFPE Samples from Breast Cancer Patients

<b>Background/Objectives</b>: Cancer characteristics are mainly due to mutations in genes that regulate key pathways. One mechanism for identifying and correcting these mutations is the Mismatch Repair System. Given the lack of data on MMR in breast cancer FFPE samples, this study aims to examine <i>hMSH2</i> and <i>hMSH6</i> gene expression in FFPE tumor biopsies. <b>Methods</b>: One hundred patients with breast cancer were included in this study, from which tumor samples were obtained. Expression of the <i>hMSH2</i> and <i>hMSH6</i> genes was evaluated by qPCR. <b>Results</b>: Out of 100 tumor samples, 89 were suitable for molecular analysis. Of these, 10 (11.23%) expressed the <i>hMSH2</i> gene and 4 (4.5%) expressed the <i>hMSH6</i> gene. No associations were found between <i>hMSH2</i> and <i>hMSH6</i> expression and tumor staging, HER2, ER, PR, or Ki-67 expression. <b>Conclusions:</b> Our results suggest that the expression of the proposed markers is decreased in breast tumorigenesis.