SIMULTANEOUS USE OF THE PCR-SSCP METHOD AND IMMUNOHISTOCHEMISTRY FOR INCREASING THE DETECTION EFFICACY OF P53 ABNORMALITIES IN HUMAN LUNG-CANCER

Malignant neoplasms possess multiple genetic abnormalities. Among thos e, p53 gene abnormalities are the most frequent in human neoplasms. To screen for p53 abnormalities, both immunohistochemistry (IHC) and the polymerase chain reaction-single strand conformation polymorphism (PC R-SSCP) methods are commonly used, but neither can detect all kinds of p53 abnormalities. In this study, by examining 35 lung cancer specime ns simultaneously by the two methods, 12 abnormal cases (34%) were det ected by IHC and 9 abnormal cases (26%) were detected by PCR-SSCP. Six abnormal (17%) and 20 normal (57%) cases showed concordant results be tween the methods, although 9 cases (26%) showed discordance, includin g 6 IHC-positive cases (17%) and 3 SSCP-positive cases (9%). Because i t is known that some p53 abnormalities are detected only by IHC or onl y by PCR-SSCP, discordant cases should be assessed as possessing abnor malities. Fifteen cases (43%) were finally assessed as abnormal, These results suggest that the two methods together can increase the sensit ivity of screening for p53 abnormalities.