Although accumulating evidence has strongly suggested that PTEN is a crucial factor in various central processes of cancer development, and although in several tumor types (e.g., non-small-cell lung cancer, prostate and breast cancer) PTEN protein status has been correlated with poor prognosis, the association between PTEN expression and clinical parameters in CRC is still controversial. The gene discussed is PTEN; the disease is non-small cell lung carcinoma.