Clinicopathological relevance of parathyroid hormone-related protein in various types of cancer tissues

Abstract

We have performed the immunohistochemical analysis for PTHrP expression in normal and 60 lung, 108 uterine, 28 breast, 42 renal, 22 ovarian and 33 gastric neoplastic tissues. Normal epithelial tissues, such as keratinocytes, renal tubules and mammary ductal cells showed positive immunoreactivity. In lung cancer, squamous (94%) and small cell (89%) carcinoma were positive regardless to the association with hypercalcemia and adenocarcinoma was negative. In uterine cervical neoplasia, 96% of squamous cell carcinoma were positive and higher immunoreactivity was observed in the cases with keratinization or prominent stromal cell interaction. 57% of brea st cancer examined were positive and immunoreactivity was most intensely observed in papillotubular and scirrhous types. Among the metastatic sites of breast cancer, skeletal lesion showed significantly higher expression of PTHrP than other sites. PTHrP was detected in 95% of renal cell carcinoma but the incidence of hypercalcemia was only 14%. In ovarian neoplasia, serous cystadenocarcinoma and clear cell carcinoma were the major histological subtypes showed positive for PTHrP. In gastric cancer, only exceptional cases of adenocarcinoma associated with heterotopic ossification showed positive for PTHrP. In conclusion, PTHrP was expressed commonly in human cancer tissues regardless to the existence of hypercalcemia. Histological subtypes were well correlated to the expression of PTHrP and surrounding tissues could modify the production of PTHrP in cancer cells.