The median mutation frequency of the 75 genes across CCLE breast cancer cell lines was 0.07 and only 9% of them (PRKDC, MAP3K1, TTN, ADGRG4, TP53, FN1, and AKAP9) were mutated in at least 50% of cell lines, suggesting that majority of these gene mutations could be recapitulated by only a few cell lines. This evidence concerns the gene ADGRG4 and breast cancer.