EGF and lung carcinoma: Consistent with this corollary, we found that EGF treatment of SPCA1 cells increased miR-26a expression and decreased PTPN13 protein levels(Figure 5A(a) & 5B), whereas gefitinib treatment of SPCA1 cells caused a significant downregulation of miR-26a levels and upregulation of PTPN13 protein levels (Figure 5A(b) & 5B), suggesting that EGFR signaling is at least partially involved in miR-26a expression in lung cancer cells.