CXCR4 and lymphoplasmacytic lymphoma: WM includes bone marrow involvement by lymphoplasmacytic lymphoma (LPL) secreting monoclonal immunoglobulin M (IgM) with somatic mutation (L265P) of myeloid differentiation primary response 88 gene (<i>MYD88</i>) in 80-90%, or various mutations of C-terminal domain of the C-X-C chemokine receptor type 4 (<i>CXCR4</i>) gene in 20-40% of cases.