ACVR2A and cancer: Tumours 2–4 furthermore harboured a truncal frameshift mutation in MSH6. Mutations in the histone methyltransferase and tumour suppressor gene PRDM2, one in combination with LOH of the second allele were also truncal in all four cases and truncal frameshift mutations of the TGFβ signalling regulator ACVR2A were detected in three cancers.