The study performed in Omsk has ascertained that incidence rates of cancer among Omsk hemoblastosis patients are 8.2 times higher than those in normal population (62 cases per 2961 patients versus 25.46 cases per 10,000 normals). Most frequently, cancer develops in lymphoproliferative diseases. Acute leukemia and chronic myeloid leukemia, for the most part, arise in females with genital and breast cancer, exposed to radiotherapy. In chronic lymphoid leukemia cancer appears in established hemoblastosis. The combination of tumors with hemoblastosis is recorded with similar frequency at the age over 39, in males and females. Combination of tumors with chronic lymphoid leukemia is attributed to immunodeficiency, typical for patients with lymphoproliferative diseases.