Expression of topoisomerase II, catalase, metallothionein and thymidylate-synthase in human squamous cell lung carcinomas and their correlation with doxorubicin resistance and with patients' smoking habits.

Forty-eight human squamous cell lung carcinomas of previously untreated patients were analyzed for resistance to doxorubicin and for the presence of topoisomerase II (Topo II), metallothionein (MT), thymidylate synthase (TS) and catalase (Cat). Significant correlations exist between resistance to doxorubicin measured by the in vitro short-term test and overexpression of MT and TS measured by immunohistochemistry. No significant correlation was found between resistance and expression of Topo II or Cat. No significant interrelationship between smoking habits of patients and expression of Topo II, MT, TS or Cat was found.