[Hormones and growth of cancer].

Estrogen and androgen play essential roles in the development of breast cancer and prostate cancer, respectively. However, only 30% of breast cancer mass and 70% of prostate cancer mass are found to be hormone-dependent when they have been treated clinically. These findings show that hormone dependency of cancer disappears rather easily. Recently, it has been found that the growth of hormone-dependent cancer is mediated through sex steroid-induced growth factors in an autocrine manner. Future studies on sex steroid-induced growth factor(s) will play important roles in order to understand the molecular mechanisms of the development and growth of breast cancer and prostate cancer.