Immunocytochemistry on Sputum Samples Predicts Prognosis of Lung Cancer.

Context: Despite sputum cytology being accepted as a simple and noninvasive diagnostic method for lung cancer, the clinical usefulness of sputum for evaluation of prognosis is yet to be explored. Validation of some of the markers in sputum for prognosis prediction will be highly useful for selective therapy.

Aims: This study was aimed to evaluate a reliable panel of immunocytochemical markers for their significance to predict survival.

Materials and Methods: We have analyzed the expression of p53, p16, galectin-3, and epidermal growth factor receptor (EGFR) proteins in sputum samples processed in a mucolytic agent/cellblock and compared the same with that of the corresponding tissue samples.

Results: Overexpression of p16 and EGFR was found to have a better survival benefit, whereas positive p53 and galectin-3 expressions had shorter period of survival. Expression patterns of all these four proteins were more or less similar in smears, cellblocks of sputum, and tissue samples except for slight changes in staining intensity which was not found to be statistically significant. No significant difference was found in the association of these proteins with survival pattern between sputum and tissue samples.

Conclusion: This is the first report of immunocytochemistry of a panel of markers on cells exfoliated in sputum samples which suggests that analysis of immunocytochemical markers in sputum samples can be attempted as a cost-effective and reliable predictor of prognosis and survival. Accumulation of mutated p53, overexpression of galectin-3, and lower expression of p16 and EGFR proteins were found to predict poor prognosis for lung cancer.