CXCR4 and cancer: Moreover, sphingomyelinase-mediated ceramide enrichment in the T cell plasma membrane disrupts C-X-C chemokine receptor type 4 (CXCR4) receptor dynamics, impairing the T cell's ability to respond to chemokine gradients and hindering T cell migration, the critical processes in T cell recruitment during autoimmune responses and cancer metastasis [189].