GNA13 is a new marker for germinal center-derived B cell lymphomas

We aim to evaluate the expression of GNA13 in germinal center (GC)-derived B cell lymphomas to evaluate its potential use as marker for diagnosis. In this study, GNA13 expression was detected by immunohistochemistry in 129 cases of B-cell non-Hodgkin lymphomas (B-NHLs) and 8 cases of angioimmunoblastic T-cell lymphoma (AITL). Furthermore, mutations in the GNA13 gene in 114 cases of B-NHLs were detected by exome sequencing. In 50 cases of diffuse large B-cell lymphoma (DLBCL), 11 cases were positive for GNA13, and all GNA13-positive cases were of the germinal center B-cell-like (GCB) subtype. In 42 cases of follicular lymphoma (FL), the GNA13-positive rate was 100% in FL grade 1, 100% in FL grade 2, 80.0% in FL grade 3 A, and 63.2% in FL grade 3B. In 6 cases of Burkitt lymphoma, 3 cases were positive for GNA13. However, in small lymphocytic lymphoma, mantle cell lymphoma and marginal zone lymphoma, GNA13 was negative or only expressed in the GC. In addition, the GNA13-positive rate was 100% in AITL. The mutation of the GNA13 gene was 27.8% (5/18) in GCB-DLBCL and 10.3% (3/29) in FL, respectively, and mutation of GNA13 occurred in cases with weak positive or negative expression of the GNA13 protein. GNA13 may be a reliable new marker for GC cells applied in the diagnosis of GC-derived B-cell lymphomas. Its deficiency or low expression may be related to the degree of invasion of GC-derived B-cell lymphomas, and may result from genetic mutations.