The immunolocalization of PGP 9.5 in normal human kidney and renal cell carcinoma

The Authors studied the localization of protein gene product (PGP) 9.5-like immunoreactivity in normal human kidney tissue and compared the results with the same immunostaining in renal cell carcinoma. PGP 9.5-like immunoreactivity was found in cells of distal convoluted tubules and in some glomerular capillaries. The cells of proximal convoluted tubules did not show any immunostaining. Sections from renal cell carcinoma showed a very low immunostaining or were negative for PGP 9.5. As PGP 9.5 is a marker of the diffuse endocrine system, the Authors believe that the stained cells of distal tubules should be considered as neuroendocrine cells. The negative reaction to PGP 9.5 antibodies in renal cell carcinoma is rather surprising since not only tumours of neuroectodermal origin, but also tumours of other origin and tissues from some chronic degenerative diseases show a positive reaction. The explication of a negative reaction in renal cell carcinoma remains open: one of the possible explanations could be the specific histogenesis of this tumour.