Western blotting assays (Fig. 3E; Additional file 4: Fig S3E) revealed that UNC5B interference in B-ALL cells treated with recombinant netrin-1 decreased the protein levels of CDK4, PCNA and Bcl-2 respectively and increased the protein levels of Bax compared with the control group treated with recombinant netrin-1.These results revealed that Unc5b might be the major receptor for netrin-1 to induce the anti-apoptotic effect of B-ALL cells. This evidence concerns the gene PCNA and precursor B-cell acute lymphoblastic leukemia.