PPIA and neoplasm: For instance, cyclophilin A can bind adaptor protein CRKII to sterically restrict the accessibility of CRKII Tyr221 to its kinase ABL1 (Abelson murine leukemia viral oncogene homolog 1) or EGFR (epidermal growth factor receptor), which thereby, inhibits CRKII phosphorylation and keeps it at the active form and enhances CRKII-mediated signaling to promote tumor cell migration [39].