PRIMARY OBJECTIVE:~I. To estimate the positive predictive value within each of the early stage testicular seminoma and nonseminoma groups using plasma miRNA 371 expression at relapse to detect germ cell malignancy.~SECONDARY OBJECTIVES:~I. To bank prospectively obtained serial liquid biospecimens for low and moderate risk of relapse patients annotated by patient level clinical data.~II. To bank prospectively collected, clinically annotated specimens for high risk patients and non-testicular primary patients in collaboration with Children's Oncology Group study AGCT 1531.~OUTLINE:~Patients undergo collection of blood every 3-6 months for up to 3 years.
This trial studies whether the blood marker micro ribonucleic acid (miRNA) 371 can predict the chance of cancer returning in patients with germ cell cancers. Studying samples of blood from patients with germ cell cancers in the laboratory may help doctors predict how likely the cancer will come back.