PARATHYROID-HORMONE RELATED PROTEIN AND INTERLEUKIN-6 MESSENGER-RNA EXPRESSION IN LARYNX AND RENAL-CELL CARCINOMAS FROM NORMOCALCEMIC AND HYPERCALCEMIC PATIENTS

Aims-To determine the expression of parathyroid hormone related protei n (PTHrP) and interleukin-6 (IL-6) mRNAs and their possible relation i n malignant tumours, derived from patients with and without hypercalca emia, commonly associated with humoral hypercalcaemia of malignancy. M ethods-PTHrP and IL-6 mRNA expression was studied by northern blot ana lysis in tumour specimens from 13 consecutive patients. Six patients ( two with hypercalcaemia) had squamous cell carcinomas of the larynx an d seven (one with hypercalcaemia) had renal cell carcinomas. Results-T here was no relation between the histological features of the tumours and the expression of either PTHrP or IL-6 mRNAs. PTHrP mRNA was detec ted in all squamous cell carcinomas, expression being highest in the t wo patients with hypercalcaemia. In the renal cell carcinomas PTHrP mR NA was expressed only in the patient with hypercalcaemia. IL-6 mRNA wa s detected in nearly all tumours studied but there was no apparent rel ation between its expression and that of PTHrP mRNA or serum calcium c oncentrations. Conclusions-PTHrP mRNA expression is increased in patie nts with hypercalcaemia but is not related to IL-6 mRNA expression. Th e results suggest a quantitative relation between PTHrP gene expressio n and hypercalcaemia, and imply that different mechanisms account for this expression in squamous and renal cell carcinomas.