This likely reflects breast cancer being much more common with over 55,000 new cases per annum (CRUK stats, https://www.cancerresearchuk.org/health-professional/cancer-statistics/statistics-by-cancer-type/breast-cancer accessed 6th November 2020), as compared with colorectal or endometrial cancer, and the consequent higher proportion of breast cancer referrals received to the MCGM, together with the higher penetrance of BRCA1/2 variants as compared with those of the MMR CPGs. The gene discussed is MRC1; the disease is breast carcinoma.