Although no significant differential PTEN expression between control tissues and tumors were observed, results suggested the loss of protein expression in a subset of canine gliomas and demonstrated an increased expression of phospho-AKT and phospho-mTor in a small group of canine astrocytomas, also corroborating previous observations [10,23]. This evidence concerns the gene AKT1 and astrocytoma (excluding glioblastoma).