RNA interference is an endogenous process, initially identified as a defense mechanism against invasion of foreign genes (e.g. viruses) in the nematode Caenorhadbitis elegans. The non-coding RNA, both long and short, are expressed in organisms and represent a process of posttranscriptional gene regulation, which is used to maintain homeostasis and regulate the expression in almost all living organisms. RNA interference is a recent discovery, but widely used to inhibit gene expression, and is already a valuable research tool to determine metabolic pathways, molecular mechanisms, and pathways of internalization signals that underlie the development of many diseases, including cancer. Cancer is a genetic and epigenetic disease that requires the accumulation of genomic inactivated tumor suppressor genes and activated oncogenes. Recently, a group identified that there are intrinsic suppressor genes and oncogenes with non-coding RNA features that have been called microRNA. These are RNA molecules of 18-24 nucleotides that, when they match the target messenger RNA, regulate the translation. RNA interference technology is a promising gene therapy in various cancers. As well as use in conjunction with chemotherapy or targeted therapies, it may represent a new way to develop resistance mechanisms for inactivation of cancer cells and improve the effectiveness of treatments.