PTEN and Ki67 expression is associated with clinicopathologic features of non-small cell lung cancer

Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) and the proliferating antigen Ki67 have been widely studied in several tumors. However, their role as indicator in non-small cell lung cancer (NSCLC) remains unknown. Here, we investigated the expression of PTEN and Ki67 in NSCLC tissues and paired normal lung tissues to identify whether these proteins are associated with lung cancer development and survival. Immunohistochemistry for PTEN and Ki67 was performed on 67 lung cancer tissues and 41 paired adjacent normal lung tissues to detect the expression of these two proteins. The expression of PTEN in NSCLC tissues (32.8%) was significantly lower than that in normal tissues (82.9%, P < 0.05). In contrast, the expression of Ki67 in NSCLC tissues (76.1%) was significantly higher than that in normal tissues (27.3%, P < 0.05). Expression of both PTEN and Ki67 were strongly associated with tumor histology, clinical stage, lymph node metastasis, differentiation and 4-year postoperative survival rate (P < 0.05). However, PTEN expression was negatively correlated with Ki67 expression (r = -0.279, P < 0.05). In conclusion, low PTEN expression and Ki67 overexpression are associated with malignant invasion and lymph node metastasis of NSCLC. These proteins may serve as diagnostic and prognostic biomarkers of NSCLC.