The immunophenotypic profile of gastric diffuse large B-cell lymphomas (DLBCL) is similar to those seen in other sites. They express CD45 and pan B-cell markers such as CD20, CD22, CD79a, and PAX-5. Monotypic immunoglobulin (surface or cytoplasmic) is variably present. Other positive markers include CD10 (shown here), BCL6, and BCL2. Some studies have reported better prognosis in CD10+ large B-cell lymphomas (5-yr survival of almost 90%) as compared to CD10-ve large B-cell lymphomas (5-yr survival of only about 30%). CD5 is present in about 10% of cases. A small number of cases show post-germinal center or plasma cell-associated markers such as CD38, VS38, and MUM1. Ki-67 labeling index is high (>20%). A minority of cases express CD30. Pan-T markers are negative.