Expression of ten-eleven translocation 2 and glutathione-S-transferase pi in colorectal cancer patients with and without type 2 diabetes mellitus

Abstract

Aims: To highlight possible correlations of type 2 diabetes mellitus (T2DM) with microscopic / macroscopic characteristics of colorectal cancer tissues, along with the expression of Ten-Eleven Translocation 2 (TET2) and glutathione-S-transferase pi (GST-pi) proteins. Materials and methods: Tumors from 46 patients were embedded in paraffin blocks, stained with hematoxylin-eosin and studied microscopically. Immunohistochemical study of TET2 and GST-pi expression was performed. The results were analyzed and correlated with T2DM as comorbidity. Results: All tumors expressed GST-pi at three levels (weak, moderate, and strong); two out of three tumors showed either weak or moderate TET2 expression. Patients without T2DM tended to have tumors with weak or no expression of TET2 (p=0.038) whereas diabetic patients’ tumors showed a significantly higher percentage of strong or moderate GST-pi expression (p=0.034). On binomial logistic regression, tumors excised from T2DM patients were 6.9 times more likely to show moderate (rather than weak and none) TET2 expression compared to tumors from non-diabetic patients (95% CI [1.33, 35.75]), and a 2.7-fold higher relative likelihood of showing strong (rather than moderate and weak) GST-pi expression (95% CI [0.63, 12.09]), taking into account sex, age, and tumor size. The association between T2DM and TET2 expression remains statistically significant in additional binomial analysis that was performed taking into account certain histological tumor characteristics. Conclusions: TET2 and GST-pi are expressed in malignant colon tumors. T2DM in CRC patients was associated with the highest observed GST-pi expression; absence of T2DM was associated with the lowest observed TET2 expression. T2DM increases the probability of observing GST-pi and TET2 expression at maximum levels, independent of specific tumor microscopic features and certain patient characteristics.