Early studies of CHEK2 mutation carriers showed an increased risk for CBC, but future studies are warranted to verify this finding.14,15 Patients at higher risk for breast cancer, such as those who have undergone mantle radiation for Hodgkin lymphoma, may be at increased risk for CBC, but few studies have verified this.16 For patients with a significant family history with no proven gene mutation or in whom genetic testing was not done, the risk of CBC varies by number and degree of the relative(s) affected by breast cancer and the age of the patient. The gene discussed is CHEK2; the disease is complete blood cell count.