Subsequently, we analyzed the gene expression profiles of BDNF in nearly 1000 human cancer cell lines extracted from the CCLE dataset, and the results revealed that the mRNA expression levels of BDNF not only were increased ubiquitously in contrast to the range of expression in the normal tissues but also varied significantly among different cancer cell lines (Kruskal-Wallis test p = 8.2e − 33, Figure 1(b)). Here, BDNF is linked to cancer.