In this context, our recent study about the RNA aptamers targeting the cancer markers of CEA, CA50 and CA72.4, will give more impetus towards the development of the applications of aptamers as the therapeutic and/or diagnostic tools and the putative internalization mechanism may open the possibility for the aptamers as the targeted delivery agent for the discovery of specific anti-cancer drugs. The gene discussed is CEACAM5; the disease is cancer.