These documents recommend that initial tumour testing be performed using IHC as part of standard pathology, MLH1 promoter hypermethylation should be conducted by genomic laboratories and routine germline testing should be offered by cancer treating teams, with clinical genetics managing families with PVs and conducting testing for those with more complex family histories.13 14 For example, patients with EC with a family history of cancer fulfilling revised Amsterdam clinical diagnostic criteria for LS may also progress to germline MMR gene testing as a first-line test.15 The gene discussed is MRC1; the disease is cancer.