While OPN has been reported to affect NF-κB expression through a variety of indirect mechanisms such as through PI3K/AKT signaling [23], integrin signaling [25, 34], and CD44 activation of MAPK/P38 [35], the specific relationship whereby OPN facilitates this mediation has not been elucidated in PCNSL. This evidence concerns the gene CD44 and primary central nervous system lymphoma.