Whole Genome Sequencing Reveals Independent Clonal Origin of Bilateral Testicular Germ Cell Tumors in 2 Patients with Pure Seminoma

Abstract

The pathophysiology of bilateral testicular germ cell tumors (TGCT) is poorly understood. It is unclear if they develop independently, arise from common germline genetic changes, or metastasize from one gonad to the other. We determined the underlying genomic alterations in two cases of bilateral TGCTs with pure seminoma using whole genome sequencing. Large chromosomal aberrations and KIT amplification were identified, but there were no shared single nucleotide variants or structural chromosomal rearrangements in paired TGCTs, suggesting they develop independently. The biological behavior of bilateral TGCTs may be distinct and the staging and prognostic evaluation of each tumor should be performed independently.