Alteration of surfactant protein A expression in renal cell carcinoma

Abstract

Surfactant protein-A (SP-A) belongs to a family of collagen-containing C-type lectins called collectins. SP-A is expressed by renal tubule epithelial cells. We investigated the distribution of SP-A in renal cell carcinomas (RCC) using immunohistochemical techniques and western blotting. We used 35 formalin fixed, paraffin embedded (FFPE) RCC tissue samples. We compared results with clinico-pathological parameters of RCC including age, sex, Fuhrman grade, tumor volume, tumor node metastasis (TNM) and clinical stage. SP-A was localized in the glomerulus and renal tubule epithelium in nontumor tissue and strong SP-A immunoreactivity was observed in tumor tissue. SP-A was expressed in the RCC tumor cells (64%) and nontumor cells (34%) in males and RCC tumor cells (90%) and nontumor cells (30%) in females. There was a significant correlation between SP-A immunoreactivity in tumor cells and gender, age, tumor diameter, Fuhrman grade and tumor diameter. Western blot analysis supported the immunohistochemical findings. We present evidence for involvement of SP-A in RCC and suggest that increased SP-A expression in RCC is associated with favorable prognosis.

Key words:

• immunohistochemistry
• renal cell carcinoma
• surfactant protein-A
• western blot

Acknowledgments

We thank David S Phelps, Department of Pediatrics, Division of Newborn Medicine, University of Pennsylvania State for the polyclonal SP-A antibody. We also acknowledge support from the University of Akdeniz, Antalya, and The University of Mehmet Akif Ersoy, Burdur, Turkey.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this paper.