Background: To investigate the clinical roles of P-gp, MRP and p53 expression and their relationship with one another in primary lung cancer.
Methods: P-gp, MRP and p53 proteins were measured in 31 paraffin-embedded lung cancer tissues and corresponding normal lung tissues by immunohistochemistry(IHC). In addition, flow cytometric analysis of P-gp and p53 was performed in 29 of 31 frozen lung cancer specimens in order to compare the results of the two methods.
Results: By IHC, positive rates of P-gp, MRP and p53 were 61.3%, 54.8%, 71.0% respectively in 31 lung cancer cases and there was no expression in all normal lung tissues. P-gp and MRP expressed only in NSCLC. The poorer the cancer cell differentiated, the lower the positive rate of P-gp expression was (P<0.05). Squamous cell carcinomas showed much higher positive rate of p53 than adenocarcinomas did (P<0.01). As compared with the non-smokers, staining for p53 was overwhelmingly positive in the smokers (P<0.05). Neither P-gp nor MRP had significant correlation with p53, however, coexpression of P-gp and MRP had a distinct statistic significance (P<0.01). By flow cytometry (FCM), the expression rates of P-gp and p53 were 65.5% and 79.3% in 29 lung cancer cases. The coincident rates of P-gp and p53 by IHC and FCM were 62.1%, 75.9% respectively.
Conclusions: P-gp and MRP overexpression may be involved in the process of lung cancer in co-ordination. Neither P-gp overexpression nor MRP overexpression has significant correlation with p53 alteration.