To further investigate the reliability of the results, PhosphoSite (http://www.Phosphosite.org) was used to distinguish known phosphorylation sites from novel phosphorylation sites. Among the identified 418 phosphorylated sites, 51% were also reported by others previously (for details, see Table S3 ). In other words, many of the phosphorylation sites were also determined by researchers with other cancer cells, further demonstrating that the phosphorylation sites detected by current strategy are reliable.