Expression and clinicopathological significance of several kinds of multidrug-resistance related factors in lung carcinoma

Objective: To investigate the expression and clinicopathological significance of several kinds of multidrug-resistance related factors in primary lung carcinoma. Methods: One hundred and thirty three cases of lung carcinoma tissues confirmed by pathological examination after surgery were included in the study and 15 cases of pericancerous tissues (5-cm apart from tumor) were selected as control. The expressions of P-gp (P-glycoprotein), multidrug resistance-associated protein (MRP), lung resistance-related protein (LRP), p53, and c-erbB2 protein in paraffin-embedded tissues were detected by immunohistochemistry. Results: (1) The positive rates of P-gp, MRP, LRP, p53 and c-erbB2 in tumor tissues were 72.2% (96/133), 40.5% (51/126), 54.1% (72/126), 59.4% (79/126), and 45.9% (61/133), respectively, which were significantly higher than that in normal controls (P<0.05) except for the P-gp (P>0.05). The expression of p53 correlated with P-gp and MRP (r=0.179 and 0.185, P=0.039 and 0.041). There were significant correlation between P-gp and LRP (r=0.264, P=0.002) as well as LRP and MRP (r=0.309, P<0.001). The expression of c-erbB-2 was associated with that of MRP, LRP, and p53 (r=0.350, 0.421, 0.541, and 0.354, respectively; P<0.001). (2) There was significant difference among the different pathologic types in P-gp, MRP, LRP, and c-erbB-2 expression (P<0.001 The difference in P-gp expression was significant in lung squamous carcinoma at different differentiation degree (P=0.049). (3) According to pathological classification/sub-classification: 1 The expression levels of LRP and c-erbB-2 were higher in the panel of neuroendocrine carcinoma than that in the panel of non neuroendocrine carcinoma (P=0.005 and 0.041, respectively); 2 There was no significant difference in the expression of MDR-related factors between the panel of bronchioloalveolar carcinoma and other types of adenocarcinoma. Conclusion: These multidrug-resistance relate factors play important roles in the intrinsic multidrug resistance of lung cancer in different degrees. They have some correlations between each other in the formation of multidurg resistance and the progression of lung cancer.