PTEN and osteosarcoma: The potential mechanisms may involved down-regulation of tumor suppressor gene, phosphatase and tensin homolog (PTEN) in osteosarcoma and breast cancer [11, 12], runt-related transcription factor 3 (RUNX-3) and collapsing-response mediator protein type 4 (CRMP4) in gastric cancer [10, 17], peroxisome proliferator-activated receptor gamma (PPARG) in chorangiocarcinoma [16] and enhanced mammalian target of rapamycin (mTOR) signaling pathway in ovarian cancer [13].