In detail, the V777L ERBB2 mutation is an activating mutation, as it strongly increases the phosphorylation of signaling proteins, indicating enhanced activity of the tyrosine kinase [84]; for this reason, BC cases with neoplastic cell HER2 V777L-mutated can be administrated with TK inhibitors (like lapatinib and neratinib) [84]. This evidence concerns the gene ERBB2 and breast cancer.