Endocrine Disrupting Pesticides, Neonatal Hormones and Risk of Testicular Germ Cell Tumors
Co-Investigators: Dr. Libby Morimoto & Dr. Robert Gunier
Background: Testicular cancers are the most common cancer occurring among male adolescents and young adults. Testicular germ cell tumors (TGCT), which makes up ~98% of testicular cancer, are part of testicular dysgenesis syndrome (TDS), a group of disorders that also include cryptorchidism, hypospadias, and impaired fertility. TDS may be a result of sex steroid imbalance during critical periods of fetal development. The incidence of TGCT has increased dramatically in the U.S. during the past 40 years, suggestive of environmental influences. However, no environmental risk factors have been established to date. Endocrine disrupting chemicals (EDCs), particularly those with estrogenic and anti-androgenic activity, may play a role in this trend. No studies have explored the potential link between fetal exposure to EDCs and risk of TGCT.
Project Goal: Using our innovative linkage of California Cancer Registry data, California birth certificates and neonatal archived dried blood specimens (DBS), we will estimate exposure to EDC pesticides during pregnancy using data from the mandatory California state registry, the Pesticide Use Reporting (PUR) database. Our proposed study will be the first to assess the effects of fetal exposure to EDCs on sex steroid hormone levels in utero and on risk of TGCT. California is the leading pesticide user in the U.S., and Latinos represent the majority of farm workers, providing a unique opportunity to examine the relationship between EDC pesticides and risk of TGCT in an ethnically-diverse population. Our proposed epidemiologic study will fill key gaps in the current knowledge of the fetal origin of TGCT.
Project Update 2021: The incidence of testicular cancer is increasing steadily in the United States, particularly among Latinos. This cancer is thought to be initiated during pregnancy and exposure to chemicals that modify the production of hormones (called endocrine-disrupting chemicals) during this critical period of fetal development may contribute to the rise in testicular cancer. To assess the relationship between fetal exposure to agricultural endocrine-disrupting pesticides (EDPs) and risk of testicular cancer among adolescents, we conducted a study in a diverse population in California. We linked birth residences of 381 testicular cancer cases and 762 healthy controls (without cancer) to the California Pesticide Use Registry (PUR) to estimate prenatal exposure to EDPs. In this study, a doubling of nearby acephate, malathion, and carbaryl applications was associated with increased risks of testicular cancer. These associations appeared to differ between Latinos and non-Latinos. We estimate that proximity to acephate applications during the year before birth may contribute as much as 10% to the total burden of testicular cancer in the California population, and that it may especially affect Latino men. Malathion and carbaryl contributed to smaller proportions of testicular cancers. Our results may partly explain the rapid rise in testicular cancer among the Latino community in California that is highly exposed to agricultural pesticides.
