For example, serine (Ser)33 appears phosphorylated in multiple phospho-proteomic analyses, including diverse types of cancer cells that include human epidermal growth factor receptor 2 (HER2)-positive, luminal A and triple negative breast cancer [2, 11] and lung cancer (http://phosphosite.org, search term = ACTB, Ser33). Here, ERBB2 is linked to cancer.