Consistently, according to the Cancer Cell Line Encyclopedia (CCLE) database [27], S6K1 mRNA expression in MCF-7 cells was remarkably higher than that in most other breast cancer cell lines; the reason for this high expression in MCF-7 cells is high level of S6K1 DNA copy number (Supplementary Fig. S3A). The gene discussed is RPS6KB1; the disease is breast cancer.