PF4 and Miyoshi myopathy: This review examines the role of chemokines that activate the CXCR2 and CXCR3 receptors in both monoclonal gammopathy of undetermined significance (MGUS) and MM, highlighting all CXC chemokines and their receptors, including CXCL1, CXCL8/IL-8, CXCL9, CXCL10, and platelet factor 4.