Expression and clinical significance of COMPASS family of histone methyltransferases in clear cell renal cell carcinoma

Abstract

The regulation of histone 3 lysine 4 (H3K4) methylation code is indispensable for the cell as any disturbance in this has been associated with many pathologic conditions, like cancer. The SET domain-containing lysine methyltransferase 2 (KMT2) family of histone methyltransferases was the first to be identified as writers of H3K4 methylation. In mammals, seven members of the KMT2 family are responsible for carrying out the bulk of H3K4 methylation. Recent studies documented alterations in various histone methylases in human cancer, which were associated with therapeutic and prognostic potential. Notwithstanding, no report has documented the role of KMT2 family of histone methyltransferases in clear cell renal cell carcinoma (ccRCC). Therefore, we examined the expression profile of all the seven KMT2 family members of histone methyltransferases in ccRCC with the aim to establish their role as prognostic or therapeutic targets. Real-time PCR was employed to study the expression of KMT2 family genes using specific primers in 50 cases of ccRCC. The mRNA levels were correlated with stage, grade, and metastasis of the tumor. Among seven genes, KMT2G was significantly up-regulated in higher stages of the tumor as compared to low stage tumors (p = 0.017). Similarly, KMT2G levels were higher in the metastatic tumor (p = 0.027). Additionally, some of the KMT2G target genes were found to be up-regulated in metastatic tumors as compared to non-metastatic. ROC curve indicated KMT2G as a good marker for discriminating metastatic tumors from non-metastatic tumors (AUC = 0.738). Thus, we conclude that KMT2G histone methyltransferase could be a good prognostic marker for ccRCC. Additionally, KMT2G can also serve as a therapeutic target for ccRCC.