CD44 and cancer: Aptamers designed against specific proteins like EpCAM, Nulceolin, HMGA-2, ABCG2, CD133, and CD44, etc. which are highly expressed in several cancers, are used in targeting RB by different strategies like conjugation with chemotherapeutic drugs like Doxorubicin, siRNA, miRNA, and pri miRNA, etc.32–35.