The ITPKB gene encodes inositol-trisphosphate 3-kinase B, an enzyme involved in the regulation of intracellular calcium levels and PI3K/Akt signaling pathways. Mutations in ITPKB have been linked to various B-cell lymphomas, including DLBCL, PMBCL and, less commonly, FL.1 ITPKB is one of a number of genes affected by aberrant somatic hypermutation in B-cell lymphomas, which complicates the interpretation of mutations at this locus. These mutations are associated with the BN2 genetic subgroup of DLBCL. The mutation pattern in ITPKB implies selection for loss-of-function mutations.