1,25-Dihydroxyvitamin D3 receptors and their relationship to histological features in renal cell carcinoma

The present studies were carried out in 11 human renal cell carcinomas to determine the presence of a receptor specific for an active form of vitamin D, 1,25-dihydroxyvitamin D3. Saturation and Scatchard analyses of the cytosol receptor for 1,25-dihydroxyvitamin D3 showed that nine tumors had a detectable level of the receptor (two fmol/mg. protein). The equilibrium dissociation constant of these receptors ranged between 46 and 380 pM and the binding capacity also ranged between 3.5 and 12.7 femtomol/mg. protein. Sucrose density gradient analysis of the specific binders revealed that the tumors had a receptor protein appearing as a single 3.6S peak. Two tumors which had only a trace of the receptor were high grade solid tumors consisting mainly of spindle or pleomorphic cells. Nine tumors possessing 1,25-dihydroxyvitamin D3 receptor consisted of clear and/or granular cells. Thus, the absence of the receptor was only accompanied by low differentiated sarcomatoid tumors with poor prognosis. However, so far, the amount of the receptor in the receptor-positive tumor did not relate to the other clinical and pathological features of the patients.