CXCR4 and cancer: In this analysis, we found that B-ALL showed a negative shRNA score in response to CXCR4 shRNA knockdown but which was also much lower than in most other human cancers (ranked 29 of 31) (Fig. 7a and Supplementary Fig. 20a), indicating that CXCR4 pathway is necessary for B-ALL cell survival in accordance with previous report33.