Clinical significance of nucleostemin and proliferating cell nuclear antigen protein expression in non-small cell lung cancer.

PURPOSE To investigate the expression and significance of the expression of nucleostemin (NS) and proliferating cell nuclear antigen (PCNA) protein in non-small cell lung cancer (NSCLC). METHODS Immunohistochemistry (streptavidin-peroxidase method) was used to detect NS and PCNA expression in 53 NSCLC samples and 15 normal lung samples. RESULTS NS protein expression was detected in 54.7% (29/53) of the NSCLC samples and 0% (0/15) of the normal lung samples (p<0.01). Furthermore, the positive expression rate of PCNA was 6.67% (1/15) in normal lung samples and 71.7% (38/53) in NSCLC samples (p<0.05). Also, the NS protein expression rate was 65.2% (15/23) in adenocarcinoma tissue samples, significantly higher than that in squamous tissues, where the NS expression rate was 46.7% (14/30) (p<0.05). In addition, the NS expression rate of 42.9% (15/35) in well or moderately differentiated tumor tissues was lower than the rate of 77.8% (14/18) in poorly differentiated tumor tissues (p<0.05). The grade of differentiation had no correlation with tumor-node-metastasis (TNM) stage and lymph node metastasis (p>0.05). Also, the positive expression rate of PCNA was significantly higher in NSCLC samples than in normal lung samples (p<0.05). In addition, a positive correlation was found between NS and PCNA expression in NSCLC (p<0.05). CONCLUSION The highly valuable tumor molecular markers, NS and PCNA, had higher expression levels in NSCLC samples. Combined detection of NS and PCNA may be important for the early diagnosis of lung cancer and individualized therapy, having also an important role in predicting tumor prognosis.