PTEN and adenocarcinoma: Inactivation or loss of PTEN expression has been reported in different solid tumors including NSCLC, breast, colorectal, endometrial, and ovarian cancers (Table 1): in NSCLCs, altered PTEN expression, has been detected in 8.2–59% and in 2.1–46% of squamous cell lung cancer (SCC, squamous hystotype) and adenocarcinoma (AD) hystotype, respectively (25).