PTEN and non-small cell lung carcinoma: Another series of early stage NSCLC specimens revealed complete loss of PTEN expression in 44% of tumors, reduced level of expression in 29% and normal expression in 27%.43 This study similarly showed methylation of PTEN in 26% of tumors with loss of heterozygosity at microsatellites in chromosome 10q23 occurring in 19% of studied specimens; however, neither was a significant predictor of PTEN protein expression.