[Clinicopathologic features and expression of OCT4 protein in testicular diffuse large B cell lymphoma]

Objective: To evaluate the expression of OCT4 and SALL4 in testicular diffuse large B-cell lymphoma (DLBCL), and the utility of an immunohistochemical (IHC) panel of OCT4, SALL4 and CD20 in the differential diagnosis of DLBCL and GCT of the testis. Methods: Eighteen cases of testicular DLBCL were selected.IHC method was used to detect the protein expression of CD20, CD3, CD5, CD10, bcl-6, MUM1, Ki-67, bcl-2, c-MYC, OCT4 and SALL4. Results: Among the 18 cases, CD20 and PAX5 were strongly and diffusely expressed in all cases, while CD21, CD3, cyclinD1, SALL4, CD117 and PLAP were all negative. CD5, bcl-2 and c-myc were expressed in 3, 16 and 8 cases, respectively. Ki-67 proliferation index ranged from 40%-95%. Bcl-2 and c-MYC were co-expressed in seven cases. Four cases were GCB-DLBCL and the remaining 14 cases were non-GCB-DLBCL, according to Hans algorithm. Nuclear OCT4 expression was present in two cases, which demonstrated moderate expression in >50% of neoplastic cells. Univariate analysis showed that clinical stage, CD5 and OCT4 expression were relevant to prognosis. Multivariate Cox regression analysis further confirmed that clinical stage, CD5 and OCT4 were independent prognostic factors in patients with testicular DLBCL. Conclusions: Care should be exercised in using OCT4 as the sole marker of germ cell differentiation in the testis. The association of OCT4 and CD5, bcl-2 co-expression raises the question of whether OCT4 expression in DLBCL may reflect more aggressive biology.