CDK8 and lung carcinoma: To verified which gene(s) can be targeted by miR-26a-5p, we overexpressed miR-26a-5p in H1299 cells and found that only PTEN expression was decreased and CDK8 and PTGS2 expression did not change in H1299 cells (Additional file 2: Fig. S5a), implying that only PTEN may be a target of miR-26a-5p in lung cancer.