MCM9 and cancer: Mice deficient in MCM8 or MCM9 are also infertile due to gonadal dysgenesis, are susceptible to chromosomal breakage, and develop ovarian tumors of unknown significance [4, 5] We don't know whether humans with MCM8 or MCM9 mutations are susceptible to cancer, however, given animal models findings, it is prudent for such individuals to be followed in high risk clinic for regular cancer surveillance.