Association of several tumor suppressor genes and oncogenes (tumor suppressor gene TP53 in Li- Fraumeni syndrome, mismatch repair genes (MMR) in Lynch syndrome, genes involved with double strand break repair system: BARD1, CHEK2, RAD51, and PALB2) with hereditary ovarian cancer has been reported. The gene discussed is CHEK2; the disease is Li-Fraumeni syndrome.