ABSTRACT
We used whole-exome and targeted sequencing to characterize somatic mutations in 103 colorectal cancers (CRC) from African Americans, identifying 20 new genes as significantly mutated in CRC. Resequencing 129 Caucasian derived CRCs confirmed a 15-gene set as a preferential target for mutations in African American CRCs. Two predominant genes, ephrin type A receptor 6 (EPHA6) and folliculin (FLCN), with mutations exclusive to African American CRCs, are by genetic and biological criteria highly likely African American CRC driver genes. These previously unsuspected differences in the mutational landscapes of CRCs arising among individuals of different ethnicities have potential to impact on broader disparities in cancer behaviors.
Subject(s)
Black or African American/genetics , Colonic Neoplasms/ethnology , Colonic Neoplasms/genetics , Mutation , Proto-Oncogene Proteins/genetics , Receptor, EphA6/genetics , Tumor Suppressor Proteins/genetics , Exome , Female , Genome-Wide Association Study , Humans , Male , White People/geneticsABSTRACT
Protein tyrosine phosphatase (PTP) receptor T (PTPRT) is the most frequently mutated PTP in human cancers. However, the cell signaling pathways regulated by PTPRT have not yet been elucidated. Here, we report identification of signal transducer and activator of transcription 3 (STAT3) as a substrate of PTPRT. Phosphorylation of a tyrosine at amino acid Y705 is essential for the function of STAT3, and PTPRT specifically dephosphorylated STAT3 at this position. Accordingly, overexpression of normal PTPRT in colorectal cancer cells reduced the expression of STAT3 target genes. These studies illuminate a mechanism regulating the STAT3 pathway and suggest that this signaling pathway plays an important role in colorectal tumorigenesis.
