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.
This work was presented in part at the 4th IASLC Lung Tumor Biology Workshop in April, 1993.