BAX and cancer: Given that MMRd cancers predictably progress through the erosion of coding homopolymers in microsatellite instability (MSI) target genes such as TGFBR2 (transforming growth factor beta receptor 2; involved in TGFβ-mediated growth inhibition) and BAX (BCL2-associated X; involved in apoptosis regulation), we hypothesized the occurrence of homopolymer variants that correlate with mutation burden.