Reduction of the effect of hormonal factors on tumor cells can be achieved by inhibiting the synthesis of sex hormones, administering analogues of the luteinizing hormone releasing factor in the pituitary gland (goserelin, leuprorelin), blocking peripheral synthesis (aromatase enzyme inhibitors) or by limiting the direct peripheral influence of sex hormones on receptors located on tumor cells (antiestrogens, antiandrogens). This evidence concerns the gene CYP19A1 and neoplasm.