The formation of ErbB1/ErbB2 or ErbB2/ErbB3 heterodimers can enhance the ligand binding, receptor tyrosine phosphorylation and cell proliferation compared to ErbB1 homodimers, thus, lapatinib has superior potency compared to single inhibitors of ErbB1 in inhibiting signal transduction of tumour proliferation and survival pathways [23]. The gene discussed is ERBB2; the disease is neoplasm.