Parathyroid Hormone-related Protein in Normal and Neoplastic Canine Tissues: Immunohistochemical Localization and Biochemical Extraction

The study investigated the localization and concentration of parathyroid hormone-related protein (PTHrP) in normal and neoplastic canine tissues using polyclonal antibodies. PTHrP was found in various tissues, including epidermal and hair follicle keratinocytes, and myoepithelial cells of several glands. In neoplastic tissues, adenocarcinomas of the anal sac showed varying levels of PTHrP staining, while squamous cell carcinomas consistently stained strongly positive. The study found no consistent relationship between tumor staining intensity and serum calcium levels. PTHrP concentrations were significantly higher in apocrine adenocarcinoma of the anal sac compared to normal tissues, suggesting a potential role for PTHrP as a paracrine or autocrine factor in these tissues.