Effect of endogenous and exogenous hormones on testicular cancer: the epidemiological evidence.

Testicular cancer is the most common type of malignancy in men aged 15-40 years. Although its incidence has increased over the past 40 years in most countries, the reasons for this rise are unclear. It has been suggested that a relative excess of endogenous estrogens during prenatal life and/or later exposures to various occupational and environmental estrogenic chemicals such as organochlorine compounds may play a causal role in the etiology of testicular cancer, but the issue is still open to further research. The purpose for this review is to summarize the epidemiologic literature about hormonal factors, endogenous hormones and environmental xenoestrogens, and testicular carcinogenesis. Future studies need to (a) consider the possible synergistic effect of exposure to environmental xenoestrogens and sex hormones, (b) focus on the most vulnerable life stages of exposure to endocrine disruptors and testicular cancer risk, (c) assess the possible additive role of androgen secretion occurring during puberty in tumor progression, and (d) consider more systematically gene-environment interactions.