NRP1 and acute lymphoblastic leukemia: Some studies demonstrated the expression of NRP‐1/CD304 in acute myeloid leukemia (AML) and B‐cell acute lymphoblastic leukemia (B‐ALL) which applied the methods of reverse transcription‐polymerase chain reaction (RT‐PCR), immunohistochemical staining and flow cytometry (FCM).17, 18, 19, 20, 21, 22