MSX1 and splenic marginal zone lymphoma: Aberrant activities of NKL homeobox genes are reported in B-cell malignancies as well, comprising HLX in Hodgkin lymphoma (HL), MSX1 in mantle cell lymphoma (MCL), NKX2-1 in diffuse large B-cell lymphoma (DLBCL), and NKX2-3 in splenic marginal zone lymphoma (SMZL), mucosa-associated lymphoid tissue (MALT) lymphoma, and DLBCL [22–25].