The authors state that they have no conflicts of interest.
Analysis of CYP27B1, Encoding 25-Hydroxyvitamin D-1α-Hydroxylase, as a Candidate Tumor Suppressor Gene in Primary and Severe Secondary/Tertiary Hyperparathyroidism†
Article first published online: 2 SEP 2008
Copyright © 2009 ASBMR
Journal of Bone and Mineral Research
Volume 24, Issue 1, pages 102–104, January 2009
How to Cite
Lauter, K. and Arnold, A. (2009), Analysis of CYP27B1, Encoding 25-Hydroxyvitamin D-1α-Hydroxylase, as a Candidate Tumor Suppressor Gene in Primary and Severe Secondary/Tertiary Hyperparathyroidism. J Bone Miner Res, 24: 102–104. doi: 10.1359/jbmr.080903
- Issue published online: 4 DEC 2009
- Article first published online: 2 SEP 2008
- Manuscript Accepted: 28 AUG 2008
- Manuscript Revised: 24 AUG 2008
- Manuscript Received: 24 APR 2008
- vitamin D;
CYP27B1, encoding 25-hydroxyvitamin D-1α-hydroxylase, converts 25-hydroxyvitamin D to its active form, 1,25-dihydroxyvitamin D, and is expressed primarily in the kidney but also in nontraditional sites including the parathyroid glands. Whereas the role of locally produced 1,25-dihydroxyvitamin D is not yet clear, it is possible that it contributes importantly to vitamin D–mediated inhibition of parathyroid cell growth, so CYP27B1 can be considered a candidate parathyroid tumor suppressor gene in that its acquired inactivation in a parathyroid cell could confer a tumorigenic growth advantage. Expression of CYP27B1 has also been reported to be altered in parathyroid neoplasms. Because detection of inactivating mutations is the central criterion for validating a candidate tumor suppressor, we directly sequenced the coding region and all splice sites of CYP27B1 in 31 sporadic parathyroid adenomas and 31 parathyroid tumors from patients with refractory secondary/tertiary hyperparathyroidism. No nonsense, frameshift, or other inactivating mutations were found, and there was no sign of homozygous deletion. Our findings indicate that CYP27B1 does not commonly serve as a classical tumor suppressor gene in the development of sporadic parathyroid adenomas or of refractory secondary/tertiary hyperparathyroidism.