Here, we demonstrate that the 599 peptide effectively delivers siRNAs designed to target CIP2A, an oncoprotein overexpressed in human head and neck squamous cell carcinomas (HNSCCs), including oral squamous cell carcinomas (OSCCs) [24], [25], [26], into oral cancer cells, mediates efficient CIP2A silencing, and consequently inhibits oral cancer cell invasiveness and anchorage-independent growth. Here, CIP2A is linked to head and neck squamous cell carcinoma.