Immunohistochemical demonstration of 14-3-3 sigma protein in normal human tissues and lung cancers, and the preponderance of its strong expression in epithelial cells of squamous cell lineage


Takashi Nakajima, MD, Second Department of Pathology, Gunma University School of Medicine, 3-39-22 Showa-machi, Maebashi, Gunma 371-8511, Japan.


In order to confirm 14-3-3 sigma (σ) protein distribution in human tissues, immunohistochemistry was performed using various paraffin-embedded human tissues. In normal human tissues, the strongest immunoreactivity for 14-3-3σ protein was observed in squamous epithelia at various sites, followed by basal cells of the trachea, bronchus and basal or myoepithelial cells of various glands. Moderate to weak 14-3-3σ immunoreactivity was seen in the epithelial cells of the alimentary tract, gall bladder, urinary tract and endometrium. In the lung, 14-3-3σ immunoreactivity was also observed in hyperplastic type II alveolar cells and metaplastic squamous cells. Immunohistochemical study using non-small-cell lung cancers revealed that 14-3-3σ immunoreactivity was stronger in squamous cell carcinomas than in adenocarcinomas. The present study revealed that 14-3-3σ expression was exclusively present in various epithelial cells and had a tendency to be stronger in cells destined for squamous epithelium or differentiating toward squamous cells in human normal and neoplastic cells.