Pivotal examples in this direction are the Michael acceptor-containing inhibitors of EGFR, which react with cysteine residue (Cys797) [50] and neratinib, which potently inhibits HER2 by covalently binding Cys805, approved by the FDA for treatment of HER2+ breast cancer in 2017 [51]. This evidence concerns the gene ERBB2 and breast cancer.