CD44 and neoplasm: Potential explanation including, (1) the efficacy of chemotherapy will be decreased in CNS and contralateral testis due to the blood brain barrier and blood-testis barrier [1]; (2) lacking of expression of integrin and adhesion molecules in PTL resulting in poor adhesion of tumor cells to the extracellular matrix [30, 31]; and (3) CD44 variant plays significant roles in lymphoma dissemination [32].