Additionally, overexpressed miR-221 was shown to enhance cisplatin resistance in osteosarcoma via Protein phosphatase 2 (PP2A) targeting [271], but also rendered pancreatic cancer cells refractory to 5-FU through regulating the gene encoding for Retinoblastoma Protein 1 (RB1) [272]. This evidence concerns the gene PTPA and osteosarcoma.