SRC and cancer: At the secondary structure level, the beta sheets at residues 68–69 and 73–74 and the isolated beta bridge between residues 63–79 in pY419 Src form a unique secondary structure environment for the phosphorylation sites S69 [36], S70 [41] and S75 [36] (Figure 7B), which are hyperphosphorylated in different cancer types.