p21WAF1 protein expression determined by quantitative immunoassay in relation to non-small-cell lung cancer aggressiveness.
OBJECTIVE
p21WAF1, a cyclin-dependent kinase inhibitor, is an important mediator of the cell-cycle arrest and tumor suppression induced by the protein p53. Although alterations of the p53 gene and its overexpression are frequent in most malignancies, including non-small-cell lung cancer (NSCLC), and may be associated with poor patient prognosis, the clinical utility of p21WAF1 expression in NSCLC has not been established.


METHODS
We have used a commercial enzyme-linked immunosorbent assay (ELISA) kit for p21WAF1 to test soluble extracts of 54 NSCLC specimens with known clinicopathological properties.


RESULTS
There was no correlation between p21WAF1 and p53 concentrations, the latter being determined by a time-resolved immunofluorometric assay developed in-house. Furthermore, p21WAF1 levels were not associated with patient age, tumor/node/metastasis (TNM) stage, lymph node metastasis, histological grade or type, or smoking history, in Mann-Whitney analysis. chi2-tests, based on cutoffs equal to the 25th, 50th, or 75th percentiles of the p21WAF1 distribution, similarly did not reveal any statistically significant associations between p21WAF1 and other clinicopathological variables. Because of the small number of patients and the median follow-up of only 18 months, a meaningful survival analysis could not be performed.


CONCLUSIONS
In summary, this preliminary study suggests that ELISA-quantified p21WAF1 levels in NSCLC extracts are weaker than p53 in terms of prognostic value and do not contribute to the further subclassification of patients.
Levesque
M A
MA
Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Ontario, Canada.
D'Costa
M
M
Diamandis
E P
EP
D000368:Aged; D002289:Carcinoma, Non-Small-Cell Lung / Q000737:chemistry* / Q000473:pathology; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000032:analysis*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005455:Fluorescent Antibody Technique; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008175:Lung Neoplasms / Q000737:chemistry* / Q000473:pathology; D008297:Male; D011237:Predictive Value of Tests; D011379:Prognosis; D016019:Survival Analysis; D016159:Tumor Suppressor Protein p53 / Q000032:analysis
C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D016159:Tumor Suppressor Protein p53