[Expression of P-gp, MRP and p53 and their clinical significance in human lung cancer tissues].
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.
Department of Respiratory Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100730, P.R.China.
M
M
Rui
L
L
Li
L
L
Liu
J
J
Wang
Z
Z
Zhang