KIT/PDGFRA Expression and Mutation in Testicular Seminoma and Ovarian Dysgerminoma

ABSTRACT

BACKGROUND: KIT and PDGFRA are tyrosine kinase receptors. Stem cell factor/KIT-mediated signaling plays a role in normal spermatogenesis, and the alteration of KIT is important in the pathogenesis of seminomas/dysgerminomas (SD). METHODS: To determine the role of expression and mutation of the KIT and PDGFRA genes, we analyzed 16 seminoma cases, 4 spermatocytic seminoma (SS) cases and 8 dysgerminoma cases for KIT and PDGFRA expression and mutation of KIT (exons 9, 11, 13, and 17) and PDGFRA (exons 12 and 18) using PCR-SSCP methods. RESULTS: KIT was immunohistochemically positive in all 24 SD cases, and one of four (25%) SS cases. PDGFRA was immunohistochemically evident in 16 of the 24 (66.6%) SD cases, and two of the four (50%) SS cases. KIT expression was significantly reduced in SS compared with seminoma (p=0.0035). Four cases (14.3%) displayed mutation in KIT exon 17 or PDGFRA exon 12. Distant metastasis was present in three cases (10.7%), one of which had a nonsense mutation in KIT. CONCLUSIONS: These results indicate that KIT is expressed in the majority of SD cases, but not in most SS cases. However, there was no significant correlation between the clinicopathologic features and mutation or expression of KIT and PDGFRA.