Relationship of p53 overexpression and up-regulation of proliferating cell nuclear antigen with the clinical course of non-small cell lung cancer.

p53 is known to play a central role in the control of cell proliferation and carcinogenesis. In non-small cell lung cancer, however, the clinicopathological studies of p53 have yielded conflicting results. In the current study, we examined 123 non-small cell lung cancers with detailed clinical information, 71 primary and 52 metastatic tumors, using formalin-fixed and paraffin-embedded surgical specimens to show the clinicopathological correlation of the immunohistochemical (DO-7) overexpression of p53. Nuclear specific p53 overexpression appeared in 48 (39%; any number of tumor cells positive) of 123 tumors (35% of primary and 44% of metastatic tumors). The distribution and intensity of staining were variable. Ninety-eight % of all tumors also expressed nuclear immunoreactivity for proliferating cell nuclear antigen (PCNA; PC 10) to a varying degree. In a univariate analysis, both p53 (> 10% of tumor cells positive; n = 11) and PCNA (> 50% of tumor cells positive; n = 32) were associated with shorter survival in the curative intent group (stages I, II, and IIIA) of 63 patients. In a multivariate analysis including all clinicopathological variables, the overexpression of p53 (but not PCNA) was found to be an independent prognostic factor (P2 = 0.0011) in the curative intent group. No correlation was detected between the immunoreactivities and patient characteristics, such as age, gender, or smoking. Double immunohistochemistry of both p53 and PCNA revealed a distinct pattern, whereas its clinicopathological correlation remained elusive. We conclude that p53 overexpression in non-small cell lung cancer (but not PCNA) is independently associated with a shortened survival and may be of prognostic significance in selected patients with earlier stage cancer.