Tumor suppressor let-7 miRNA, known to be associated with many tumors, was delivered intratumorally in a mouse model of non-small-cell lung cancer, which led to reduction of tumor burden.106 Several studies suggest that let-7 acts through direct repression of KRAS and c-MYC oncogenes.107 Another deregulated miRNA associated with several cancers is miR-34. This evidence concerns the gene MYC and neoplasm.