KDR and cancer: Among genes with tumor-specific retentions, genes with known driver functions in cancer were rediscovered, including EGFR, ROS1, ATM and KDR. Additionally, other growth factor genes were also found with retained introns in tumor samples, such as PDGFRB (platelet-derived growth factor receptor, beta polypeptide), TGFBI (transforming growth factor, beta-induced), EGF (epidermal growth factor), IGF2R (insulin-like growth factor 2 receptor), and ERBB2 (v-erb-b2 erythroblastic leukemia viral oncogene homolog 2), which are also involved in tumor evolution in various studies [58-62].