CM from human breast cancer cell lines SUM159, MDA-MB231, and MCF7 showed over a 21-, 15-, and 11-fold higher concentration of soluble CrkL than CM from normal breast epithelial cell line MCF10A (545 ± 7, 393 ± 18, 289 ± 10 vs. 26 ± 5pg/mL, respectively) (Figure 2). This evidence concerns the gene CRKL and breast cancer.