The Correlation of Histopathologic Parameters With Mismatch Repair Protein-deficient Subgroups and MLH1 Methylation in Endometrial Carcinomas

Abstract

There are limited data regarding the correlation of clinical and pathologic parameters with mismatch repair (MMR) protein-deficient subgroups and methylation status. In this study, we analyzed the status of MMR proteins in resection specimens of 198 consecutive endometrial carcinomas and the methylation status in tumors with MLH1 and PMS2 deficiency. We, therefore, assessed the correlation of clinical and pathologic parameters with MMR protein-deficient subgroups. Univariate analysis revealed that deeper myometrial invasion and the presence of tumor-associated lymphocytes were more frequently observed in tumors with MMR protein deficiency (P=0.023 and 0.001, respectively). The multivariate logistic regression analysis revealed that only the presence of tumor-associated lymphocytes was significantly associated with MMR protein deficiency (P=0.002, odds ratio=2.674, 95% confidence interval=1.418-5.045). We also compared MLH1 and PMS2 deficiency with other protein deficiency regarding clinical and pathologic parameters. Furthermore, we compared MLH1 methylated tumors with MMR protein-deficient nonmethylated tumors regarding clinical and pathologic parameters. MLH1 was methylated in 51 of 54 tumors with MLH1 and PMS2 deficiency. In univariate analysis, a larger tumor size was significantly associated with MLH1 and PMS2 deficiency and with MLH1 methylation (P=0.004 and 0.005, respectively). The multivariate logistic regression analysis revealed that a larger tumor size was significantly associated with MLH1 and PMS2 deficiency and MLH1 methylation (P=0.002, odds ratio=14.222, 95% confidence interval=2.560-79.026, P=0.008, odds ratio=22.222, 95% confidence interval=2.220-222.395, respectively). Our results showed a slightly higher rate of MLH1 and PMS2 deficiency (34.3%) than in previous studies. This may likely be due to ethnic differences in frequency of various mutations.