The aim of this study was to perform a systematic review of the literature and to evaluate and compare cancer risk in our series of 631 Polish HNPCC families including 279 families with identified mismatch repair (MMR) gene mutations (referred as Lynch syndrome (LS) families) in order to suggest optimal management of ovarian and endometrial cancer for female MMR mutation carriers and their close relatives. Here, MRC1 is linked to cancer.