One of these responses is the endothelial release of NRG (neuregulin)-1-a paracrine growth factor activating ErbB2 (erythroblastic leukemia viral oncogene homolog B2), ErbB3, and ErbB4 receptor tyrosine kinases on various targets cells.
Several of these genes are involved in signal transduction pathways that may be critical for maintaining cell transformation; some examples are avian erythroblastic leukemia viral oncogene homolog 3 ( ERBB3), neuregulin 1 ( NRG1), fibroblast growth factor 9 ( FGF9), and fibroblast growth factor receptor-1 ( FGFR1).