Is the Wnt/β catenin signalling pathway activated in Seminoma?: An immunohistochemical study

The loss of reduction of some adhesion molecules is associated with the invasive phenotype of carcinomas. The aim of this paper was to study the expression of some proteins related to the Wnt/β catenin signalling pathway in seminomas by immunohistochemical techniques in order to assess the contribution of this pathway to the tumoral development.

Immunohistochemistry for E-cadherin, β-catenin, vimentin, C-Myc, cyclin D1 (CD1) and placental alkaline phosphatase. (PALP) was carried out in 24 archival tissue blocks of seminomas. Two cellular lines were used as E-cadherin and β-catenin controls. (JKT-1 and TCam-2).

E-cadherin was positive in two seminomas and in one carcinoma in situ. (CIS), showing a membranous pattern. βcatenin was principally expressed in Sertoli cells, in some malignant gonocytes of CIS and in the membranes of seminomatous cells. No β-catenin immunostaining was detectable in the cytoplasm and the nuclei of neoplastic cells. Seminomas were weakly possitive for vimentin in 11/24 cases. None of the tumors displayed expression of C-Myc or CD1.

The results does not indicate the activation of the Wnt pathway, due to the lack of vimentin expression in 13/24 seminomas, the low expression in the rest of the cases, the lack of β-catenin in nuclei and the absence of CD1 and C-Myc expression. Further work is needed to confirm these observations and to test other signaling pathways in seminomas.