OBJECTIVE: Some patients with parathyroid carcinoma present with an over-production of nontruncated amino-terminal (NT-N) parathyroid hormone (PTH), a post-transcriptionally modified form of PTH(1-84). This is usually picked up on an elevated whole (W) PTH (third-generation)/total (T) (second-generation) PTH assay ratio (N > 0·8). PATIENTS AND DESIGN: Two parathyroid cancer patients with several episodes of hypercalcaemia and multiple surgeries are described. In both patients, W-PTH, T-PTH and circulating PTH molecular forms separated by high-pressure liquid chromatography (HPLC) were measured with the same assays. qPCR was used to study HRPT2 gene mutation. RESULTS: The first patient had total calcium of 3·8 and 3·22 mmol/l before the fourth and fifth surgeries, and third/second-generation PTH ratios of 2·95 and 3·6, respectively. After the fourth surgery, the ratio remained normal for 1 year and increased progressively to 3·6 over 15 months. This preceded hypercalcaemia by 6 months. The ratio became normal after the fifth surgery. HPLC analysis disclosed an over-expression of NT-N PTH to 82·2% (N < 10%) relative to hPTH(1-84) before the fifth surgery. A deletion of all the tested exons of the HRPT2 gene was identified. In the second patient, W-PTH/T-PTH ratio was 0·89 when serum calcium was 3·3 mmol/l. NT-N PTH was also over-expressed at 51·9%. An inactivating mutation of the HRPT2 gene was also identified. CONCLUSIONS: This may suggest that a progressive rise in third/second-generation ratio may have possible clinical utility to monitor parathyroid cancer recurrence. A possible association between NT-N PTH overproduction and HRPT2 gene inactivation is also suggested.
OBJECTIVE: Some patients with parathyroid carcinoma present with an over-production of nontruncated amino-terminal (NT-N) parathyroid hormone (PTH), a post-transcriptionally modified form of PTH(1-84). This is usually picked up on an elevated whole (W) PTH (third-generation)/total (T) (second-generation) PTH assay ratio (N > 0·8). PATIENTS AND DESIGN: Two parathyroid cancerpatients with several episodes of hypercalcaemia and multiple surgeries are described. In both patients, W-PTH, T-PTH and circulating PTH molecular forms separated by high-pressure liquid chromatography (HPLC) were measured with the same assays. qPCR was used to study HRPT2 gene mutation. RESULTS: The first patient had total calcium of 3·8 and 3·22 mmol/l before the fourth and fifth surgeries, and third/second-generation PTH ratios of 2·95 and 3·6, respectively. After the fourth surgery, the ratio remained normal for 1 year and increased progressively to 3·6 over 15 months. This preceded hypercalcaemia by 6 months. The ratio became normal after the fifth surgery. HPLC analysis disclosed an over-expression of NT-NPTH to 82·2% (N < 10%) relative to hPTH(1-84) before the fifth surgery. A deletion of all the tested exons of the HRPT2 gene was identified. In the second patient, W-PTH/T-PTH ratio was 0·89 when serum calcium was 3·3 mmol/l. NT-NPTH was also over-expressed at 51·9%. An inactivating mutation of the HRPT2 gene was also identified. CONCLUSIONS: This may suggest that a progressive rise in third/second-generation ratio may have possible clinical utility to monitor parathyroid cancer recurrence. A possible association between NT-NPTH overproduction and HRPT2 gene inactivation is also suggested.
Authors: Mishaela R Rubin; Shonni J Silverberg; Pierre D'Amour; Jean-Hugues Brossard; Louise Rousseau; James Sliney; Tom Cantor; John P Bilezikian Journal: Clin Chem Date: 2007-06-28 Impact factor: 8.327
Authors: William F Simonds; Christiane M Robbins; Sunita K Agarwal; Geoffrey N Hendy; John D Carpten; Stephen J Marx Journal: J Clin Endocrinol Metab Date: 2004-01 Impact factor: 5.958
Authors: Trisha M Shattuck; Stiina Välimäki; Takao Obara; Randall D Gaz; Orlo H Clark; Dolores Shoback; Margaret E Wierman; Katsuyoshi Tojo; Christiane M Robbins; John D Carpten; Lars-Ove Farnebo; Catharina Larsson; Andrew Arnold Journal: N Engl J Med Date: 2003-10-30 Impact factor: 91.245