Sheen YS, et al. - The present study was undertaken to investigate the mRNA expression profile of erlotinib-treated HMEC-1 s and distinguished IQ motif containing GTPase activating protein 1 (IQGAP1) as the most consistently upregulated transcript and protein. Researchers determined that epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors reduced the proliferation of HMEC-1 (immortalized human dermal microvascular endothelial cells) and HMVEC (human dermal microvascular endothelial cells), and also hindered the phosphorylation of EGFR and ERK. Remarkably, raised IQGAP1 expression was correlated with decreased transendothelial electrical resistance and increased vascular permeability in vitro. In dermal endothelial cells, erlotinib produces adherens junction dysfunction by modulating the expression of IQGAP1.