PTEN and sarcoma: These tumors may be associated with microsatellite instability and mutations in phosphatase and tensin homolog, phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha, Kirsten rat sarcoma and Catenin Beta 1 (PTEN, PIK3CA, K-ras and CTNNBI) [4].