Relationship of p53 oncoprotein and proliferating cell nuclear antigen expression between primary and relapsing...

To investigate whether p53 and proliferating cell nuclear antigen (PCNA) are maintained at relapse of non-small cell lung cancer (NSCLC), we examined tumor materials from nine patients with NSCLC who had undergone resection for primary cancer and also a second resection for its relapse to the lung. In each case, histological types of primary and relapsing tumor were identical (eight adenocarcinomas and one squamous cell carcinoma). Immunohistochemical staining analysis for p53 oncoprotein expression revealed that seven of the nine cases had identical p53 expression in primary and relapsing tumor (p53 positive in three cases and negative in four) and that in the remaining two cases, p53 positive conversion during relapse was found in one case and negative conversion in one. Immunostaining for PCNA expression revealed that PCNA expression was observed in five primary tumors, and at relapse these cases were also PCNA positive. Three of the remaining four cases showed PCNA positive conversion during relapse. This study of a small number of patients indicates that results of p53 and PCNA immunostaining of resected materials of NSCLC seem to be of little significance for predicting future relapse.