Gcet1 immunohistochemical expression in major lymphoma subtypes. (A-D) Gcet1 expression in follicular lymphoma. Gcet1⁺ cells were found in the germinal center (A), also in areas of marginal zone differentiation (B), and diffuse areas (C). At higher magnification (D), the diffuse and heterogeneous staining of the neoplastic population. (E,F) Gcet expression in Burkitt lymphoma. In BL-positive cases, the staining was diffuse, with the characteristic cytoplasmic localization (E). However, some BL cases were negative (F). (G,H) Gcet1 expression in DLBCL. (I) Gcet1 expression in T/HRBCL. In positive cases, Gcet1 selectively stained the tumoral B cells. The pattern of staining was similar to that found in NLPHL (J) and in positive cases of LRCHL (K). However, a subgroup of LRCHL (L) and all the other classic HL subtypes remained negative for Gcet1.