The incidence of testicular germ cell tumors (TGCT) has increased during the better part of the twentieth century and is of particular concern as it primarily affects young men. Though the tumor is relatively infrequent in the population as a whole, TGCT is the most common cancer among U.S. males in the age group 15-34 years. Despite the increases in TGCT rates, the etiology is still poorly understood. The only well described risk factors for TGCT are cryptorchism, family history of TGCT and personal history of TGCT. Therefore, to understand better the environmental and genetic determinants of TGCT risk, a case-control study was conducted among members of the U.S. Armed Forces. The study included men who had donated a blood sample to the Department of Defense Serum Repository (DoDSR) between the years 1989 and mid-2003. All DoDSR donors who developed TGCT were matched to DoDSR donors who had not developed TGCT.
A total of 1682 servicemen were enrolled in the study; 754 cases and 928 controls. Of these study participants, 1303 men (77%, 590 cases, 713 controls) donated buccal cell samples. In addition to the servicemen, a total of 1090 mothers of servicemen were enrolled and 952 (87%) provided a buccal specimen. The DoDSR serum samples have been assayed for levels of organochlorine pesticides, polychlorinated biphenyl congeners, insulin-like growth factors, gonadotropins and steroid hormones DNA isolated from the buccal cell specimens have been genotyped for polymorphisms in the hormone metabolism pathway, immune function pathway, insulin-like growth factor pathway and for single nucleotide polymorphisms in the 8q24 locus. In addition, a genome-wide association study has completed. Statistical analyses of the questionnaire data are continuing.
Note: Genotype data from this study will be made available in dbGaP once the initial publication is in press at a peer-reviewed journal.