Mutation and Expression of a Candidate Tumor Suppressor Gene EPB41L3 in Gastric and Colorectal Cancers

Erythrocyte Membrane Protein Band 4.1 Like 3 (EPB41L3) is candidate tumor suppressor gene (TSG) in various cancers. EPB41L3 downregulation has been identified in many solid cancers including gastric (GC) and colorectal cancers (CRCs), but somatic inactivating mutation along with protein expression in cancers are largely unexplored. The aim of our study was to find whether EPB41L3 gene was mutated and expressionally altered in GC and CRC. EPB41L3 gene has a mononucleotide repeat in the coding sequence that could be mutated in cancers with high microsatellite instability (MSI-H). We analyzed 79 GCs and 124 CRCs, and found that only one CRC with MSI-H (1.3%) harbored the frameshift mutation within the repeat. In immunohistochemistry, loss of EPB41L3 expression was identified in 49% of GCs and 42% of CRCs. Our data may indicate EPB41L3 that loss of expression but not frameshift mutation may play a role in GC and CRC development by inhibiting TSG functions of EPB41L3.