THE PATTERN OF P53 AND P21(WAF1 CIP1) IMMUNOREACTIVITY IN NON-HODGKINS-LYMPHOMAS PREDICTS P53 GENE STATUS/

P53 and p21(WAF1/CIP1) (p21) immunostaining was performed on 92 non-Ho dgkin's lymphomas (NHLs), and the staining pattern correlated with the presence or absence of p53 hot spot mutations as detected by PCR-SSCP of exons 5-8 and direct sequencing. Twenty-nine of 92 lymphomas overe xpressed p53, and 17 overexpressed p21. Of the p53 overexpressing lymp homas, 14 also overexpressed p21, and none of these 14 harbored a dete ctable hot spot mutation. However, mutations were detected in 13 (87%) of 15 p53 overexpressing, p21 negative lymphomas. One of the 63 p53-n egative lymphomas harbored a detectable hot spot mutation, and it was also negative for p21. These results demonstrate that among NHLs that overexpress p53 protein, those which also show p21 overexpression do n ot harbor p53 hot spot mutations, and furthermore, provide evidence th at the transactivating function of p53 is retained. On the other hand, p53 overexpression in NHLs that lack p21 expression is usually indica tive of p53 gene mutation.