[Expressions of 8-OH-dG, k-ras, and p53 genes in pleural effusion cells and their clinical significances].

Background & Objective: Oxidative DNA damage plays an important role in carcinogens-induced carcinogenesis. 8-hydoxy-2deoxy-guanosine (8-OH-dG), a biomarker of oxidative DNA damage, plays important roles in initiation, progression, and prognosis of lung cancer, and closely relates with mutations of k-ras and p53 genes in carcinogenesis of lung tissue. This study was to detect protein expressions of 8-OH-dG, k-ras, and p53 genes in lung cancer tissues, and to analyze their values in distinguished diagnosis of lung cancer.

Methods: Protein levels of 8-OH-dG, k-ras, and p53 in pleural effusion cells from 53 patients with lung cancer, and 53 patients with other benign lung diseases were detected by immunocytochemistry.

Results: Positive rates of 8-OH-dG, k-ras, and p53 protein in cancer group were significantly higher than those in benign disease group [75.5% (40/53) vs. 15.1% (8/53), P < 0.01; 64.2% (34/53) vs. 3.8% (2/53), P < 0.01; and 69.8% (37/53) vs. 18.9% (10/53), P < 0.01; respectively]. Protein levels of 8-OH-dG, k-ras, and p53 protein in cancer group were 1.68+/-1.21, 1.32+/-1.06, and 1.57+/-1.15,respectively. Rank correlation analysis showed that protein expression of 8-OH-dG positively correlated with those of k-ras (RS=0.643, P < 0.01), and p53 (RS=0.827, P < 0.01)u protein expression of k-ras positively correlated with that of p53 (RS=0.897, P < 0.01).

Conclusions: Protein expressions of 8-OH-dG, k-ras, and p53 are up-regulated in pleural effusion cells of lung cancer, and have mutual relations. They may be used as reference markers in diagnosing and screening for lung cancer.