[897] Immunohistochemical Study of Spermatocytic Seminoma of the Testes, with Special Reference to the Re-Assessment of C-Kit.

Shojiroh Morinaga. Kitasato Institute Hospital, Tokyo, Japan

Background: It has been believed that spermatocytic seminomas of the testes show exclusively negative reactions for immunohistochemical markers specific for classical seminomas and intratubular malignant germ cells, including c-kit, placental alkaline phosphatase (PLAP), OCT4, etc. However, a few reports contradicting this general opinion, which have demonstrated the expression of c-kit in some subsets of patients with spermatocytic seminomas, have also been published. Thus, the significance of c-kit immunohistochemistry in spermatocytic seminoma has not yet been clarified.
Design: Formalin-fixed paraffin-sections prepared from 10 patients of spermatocytic seminoma of the testes, including 1 patient from our own institution and 9 referred from other institutions, were immunohistochemically stained with 5 different commercially available antibodies against c-kit, including 2 monoclonal rabbit antibodies. In addition, the expressions of PLAP, OCT4, NANOG, D2-40, VASA and SALL4 were also simultaneously examined.
Results: Sections from seven to nine of the 10 patients showed positive staining for c-kit determined with each of the 5 antibodies to c-kit. The staining pattern was diffuse and predominant in the cell membrane. Non-neoplastic spermatogonia of the seminiferous tubules around the tumors also showed positive staining. Stainings for all of PLAP, OCT4, NANOG and D2-40 were negative in all cases. All of the 10 cases were positive for SALL4 and VASA.
Conclusions: Spermatocytic seminoma cells and non-neoplastic spermatogonia showed positive staining for c-kit with most of the currently available antibodies against c-kit. These findings could provide new insight into the histogenesis of spermatocytic seminoma.
Category: Genitourinary (including renal tumors)

Tuesday, March 1, 2011 1:00 PM

Poster Session IV # 78, Tuesday Afternoon


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