Surfactant Protein A Detection in Large Cell Carcinoma of the Lung

Abstract

Large cell carcinomas of the lung are undifferentiated malignant epithelial tumors that lack cytologic features of small cell carcinoma, glandular cell carcinoma, or squamous cell differentiation. Lung surfactant protein A (SP-A) is produced by alveolar type II cells and Clara cells. Most bronchioloalveolar carcinomas of the lung react positively for SP-A. Positive SP-A staining of large cell carcinoma of the lung could indicate that at least part of these tumors have the same cellular origin or differentiation as bronchioloalveolar carcinoma. The authors determined the SP-A staining of 63 large cell carcinomas of the lung by IHC. In 20 of the 63 (32%), the tumors stained positive for SP-A. This may imply that about one third of large cell carcinomas of the lung have a similar cellular origin or differentiation as bronchioloalveolar carcinoma. The significance of this finding for prognosis and new forms of treatment remains to be determined.

An update on clinicopathological, immunohistochemical, and molecular profiles of colloid carcinoma of the lung

“…Also noted was the presence of entrapped non-neoplastic pneumocytes that stained for TTF-1, a reaction that can be misinterpreted as positivity in the tumor cells. The lack of surfactant in most of our cases parallels the findings of Uzaslan et al [19], who reported that only tumors with alveolar type 2 and/or Clara cell-type features are surfactant positive. This association strengthens the finding of lack of immunoreactivity with TTF-1, noted in the most tumors included in the current study.…”