Frameshift Mutations in Repeat Sequences of ANK3, HACD4, TCP10L, TP53BP1, MFN1, LCMT2, RNMT, TRMT6, METTL8 and METTL16 Genes in Colon Cancers

Diminished ANK3 contributes to cell survival by inhibiting detachment-induced apoptosis. TP53BP1 that interacts with p53 and MFN1 that encodes a mitochondrial membrane protein are considered to have tumor suppressor gene (TSG) functions. HACD4 involving fatty acid synthesis and TCPL10 with transcription regulation functions are considered TSGs. Many genes involved in DNA methylations such as LCMT2, RNMT, TRMT6, METTL8 and METTL16 are often perturbed in cancer. The aim of our study was to find whether these genes were mutated in colorectal cancer (CRC). In a genome database, we observed that each of these genes harbored mononucleotide repeats in the coding sequences, which could be mutated in cancers with high microsatellite instability (MSI-H). For this, we studied 124 CRCs for the frameshift mutations of these genes and their intratumoral heterogeneity (ITH). ANK3, HACD4, TCP10L, TP53BP1, MFN1, LCMT2, RNMT, TRMT6, METTL8 and METTL16 harbored 11 (13.9%), 3 (3.8%), 0 (0%), 5 (6.3%), 1 (1.3%), 2 (2.5%), 4 (5.1%), 3 (3.8%), 2 (2.5%) and 2 (2.5%) of 79 CRCs with MSI-H, respectively. However, we found no such mutations in microsatellite stable (MSS) cancers in the nucleotide repeats. There were ITH of the frameshift mutations of ANK3, MFN1 and TP53BP1 in 1 (6.3%), 1 (6.3%) and 1 (6.3%) cases, respectively. Our data exhibit that cancer-related genes ANK3, HACD4, TP53BP1, MFN1, LCMT2, RNMT, TRMT6, METTL8 and METTL16 harbor mutational ITH as well as the frameshift mutations in CRC with MSI-H. Also, the results suggest that frameshift mutations of these genes might play a role in tumorigenesis through their inactivation in CRC.