ACVR2A and neoplasm: Tumour-type specificity of frameshift MSI is evident for some well-known targets of MSI, such as ACVR2A (52% of MSI-H tumours) and TGFBR2 (44%) (enriched in both COAD and STAD; P<0.05, one-tailed Fisher's exact test) as well as RPL22 (31%), RNF43 (31%), MLL3 (27%), PRDM2 (21%), JAK1 (16%) and APC (3%) (Supplementary Fig. 4b; Supplementary Data 4)27, 28, 29.