ERBB2 and breast cancer: For example, it has been shown that transcriptional changes in response to the HER2 inhibitor lapatinib in HER2-positive breast cancer leads to the upregulation of multiple receptor tyrosine kinases (RTKs), including EGFR, IGF1R, INSR, FGFR2 and DDR2, which confer compensatory survival signalling and drug resistance [13].