This mechanism is in agreement with ability for miR-26a to arrest the cell cycle in ACTH-secreting pituitary adenomas, lung carcinoma32 and hepatocellular carcinoma.33 It is also consistent with the findings that let-7a arrests the cell cycle of human hepatocellular carcinoma.19,34 In addition, the miR-26a and let-7a mimics decreased the ability of malignant melanoma cells to migrate across the Transwell membrane, suggesting that miR-26a and let-7a may inhibit invasiveness and metastasis of melanoma. This evidence concerns the gene POMC and hepatocellular carcinoma.