The myocardium, which has a high metabolic activity, responds to metabolic disorders and energy imbalance induced by a growing malignant tumor. In addition, the tumor itself can produce substances that directly affect metabolic processes and the life cycle of cells not involved in the neoplastic process, including cardiomyocytes. This review summarized and systematized current data on individual aspects of detrimental effects of oncogenes and tumor-related factors on the heart muscle and morpho-functional changes in the cardiovascular system of oncology patients. Also, the authors described in detail development of these pathogenetic mechanisms.