Primary hyperparathyroidism and osteosarcoma: examination of a large cohort identifies three cases of fibroblastic osteosarcoma

Primary hyperparathyroidism and sarcoma: A case report and literature review

ABSTRACT

The relationship between primary hyperparathyroidism (PHPT) and bone sarcoma is debatable, especially after wider use of teriparatide treatment, concerns have intensified on the issue. Extensive search in English literature revealed 10 cases reported having PHPT and sarcomas. Besides, three cases of bone sarcoma occurring after teriparatide treatment had been reported. Hereby, we report a 51-year-old woman with a prolonged history of PHPT. She was diagnosed with chondrosarcoma 9 years after refusal and lack of treatment for PHPT. She was cured surgically for both chondrosarcoma and parathyroid adenoma at 1-year interval. So far, large cohorts did not show an increase in the incidence of bone sarcomas in PHPT. Several case observations, including the current one, as well as data from in vitro and rat studies, pointed out prolonged parathormone exposure, may be a risk for bone sarcomas. Under these circumstances, a safer attitude on individual basis would be the prevention of prolonged parathormone exposures.

Undifferentiated Pleomorphic Sarcoma and Hyperparathyroidism in an Adolescent Male: A Case Report and Review of Hyperparathyroidism-associated Sarcomas

The association between hyperparathyroidism and sarcoma is extremely rare with other reported cases describing the development of osteosarcoma and chondrosarcomas in middle-aged adults. This case describes an adolescent male with hyperparathyroidism and a pathologic fracture of a biopsy-proven brown tumor in the distal right femur. The fracture healed but later developed an undifferentiated pleomorphic sarcoma of the bone at the site of the known brown tumor. Although in vitro and in vivo studies have demonstrated the risks of elevated parathyroid hormone with development of sarcomas, there is limited evidence of a human association. The effects of elevated parathyroid hormone on the skeletally immature bone in the setting of sarcoma formation are currently not well understood without current description of adolescent hyperparathyroidism-associated sarcomas. This case highlights a sarcoma originating at a pathologically proven brown tumor within an adolescent male, discusses the association of sarcoma with hyperparathyroidism, and reviews the other nine reported cases in the literature.

Ras-ERK1/2 Signaling Promotes The Development Of Osteosarcoma By Regulating H2BK12ac Through CBP

Background

H2BK12ac is an important histone acetylation pattern of H2B, which has been reported in several cancers. However, whether H2BK12ac joins in Ras-ERK1/2 activation-induced osteosarcoma (OS) cell behaviors remain unclear. The study explored this peradventure and revealed the underlying mechanism.

Methods

MG-63 cells were transfected with pEGFP-N1, pEGFP-Ras^WT and pEGFP-K-Ras^G12V/T35S, H2BK12ac and ERK1/2 expression levels were analyzed by Western blot. Effects of H2BK12ac on cell viability, migration, colony formation and cell cycle were investigated by MTT, Transwell, soft-agar colony formation and flow cytometry assays. RT-qPCR and ChIP were performed to study the effect of H2BK12ac and CBP on ERK1/2-downstream gene transcriptions.

Results

H2BK12ac was specifically down-regulated by Ras-ERK1/2 activation in MG-63 cells. Down-regulated H2BK12ac participated in regulating cell proliferation and migration of MG-63 cells, meanwhile, affected the transcription of ERK1/2-downstream genes. Additionally, silence of HDAC1 up-regulated H2BK12ac expression, and inhibited the promoting effect of Ras-ERK1/2 on MG-63 cells' proliferation, migration and RNA expression levels of ERK1/2-downstream genes. Further, the degradation of CBP mediated by MDM2 was discovered to be linked to Ras-ERK1/2 activation-induced H2BK12ac down-regulation.

Conclusion

These findings from the study demonstrated that Ras-ERK1/2 signaling could promote the development of OS via regulating H2BK12ac through MDM2-mediated CBP degradation.

Anabolic treatment for osteoporosis: teriparatide

Teriparatide is a safe and effective anabolic treatment for osteoporosis. In postmenopausal women, it increases BMD and decreases vertebral fractures by about 70% and non-vertebral fractures by about 45% (although there is no evidence that it prevents hip fractures). The current evidence indicates that it should be administered for a single course of 24 months, and followed with an anti-resorptive agent to maintain the BMD gain. There is no clear benefit to repeated or cyclical treatment. Combination treatment, particularly with denosumab achieves greater BMD increase than either agent alone, but there are no available fracture data for combination treatment. There are some unknowns; most fundamentally why daily PTH administration is anabolic to bone when continuous high PTH is catabolic. Also, a better understanding of why the anabolic action declines with time and why there is a poor response to repeated treatment may help us to use teriparatide more effectively, and increase our understanding of bone biology and osteoporosis pathophysiology.

Osteosarcoma in a Patient With Pseudohypoparathyroidism Type 1b Due to Paternal Uniparental Disomy of Chromosome 20q

It is assumed that a persistent high level of parathyroid hormone (PTH) might have a relation with bone malignancy. However, there has been no report of osteosarcoma associated with pseudohypoparathyroidism type 1b (PHP1b), which is accompanied by high PTH. PHP1b is the result of resistance to PTH in certain end-organ tissues, especially the kidney; the response in bone is unaffected because it normally expresses stimulatory G protein equally from both parental alleles. A 21-year-old male, presenting with gum swelling at the right mandible, was referred to a dental clinic. A curative surgical resection by segmental mandibulectomy was performed and the pathologic findings of the mass were consistent with osteoblastic osteosarcoma. His laboratory results showed a low calcium level despite high PTH, and he did not have any features of Albright hereditary osteodystrophy; therefore, PHP1b was suspected. Multiplex ligation-dependent probe amplification and microsatellite marker analyses of chromosome 20 confirmed the diagnosis and identified paternal uniparental disomy of chromosome 20q (patUPD20). To the best of our knowledge, this is the first report of osteosarcoma in a patient with PHP1b due to patUPD20. © 2017 American Society for Bone and Mineral Research.

Intermittent Administration of Parathyroid Hormone [1-34] Prevents Particle-Induced Periprosthetic Osteolysis in a Rat Model

We examined whether intermittent administration of parathyroid hormone [1-34] (PTH[1-34]; 60 μg/kg/day) can prevent the negative effects of titanium (Ti) particles on implant fixation and periprosthetic osteolysis in a rat model. Eighteen adult male rats (12 weeks old, bones still growing) received intramedullary Ti implants in their bilateral femurs; 6 rats from the blank group received vehicle injections, and 12 rats from the control group and PTH treatment group received Ti particle injections at the time of operation and intra-articular injections 2 and 4 weeks postoperatively. Six of the rats that received Ti particles from the PTH group also received PTH[1-34] treatment. Six weeks postoperatively, all specimens were collected for assessment by X-ray, micro-CT, biomechanical, scanning electron microscopy (SEM), and dynamic histomorphometry. A lower BMD, BV/TV, Tb.N, maximal fixation strength, and mineral apposition rate were observed in the control group compared to the blank group, demonstrating that a periprosthetic osteolysis model had been successfully established. Administration of PTH[1-34] significantly increased the bone mineral density of the distal femur, BV/TV, Tb.N, Tb.Th, Tb.Sp, Con.D, SMI, and maximal fixation strength in the PTH group compared to that in the control group. SEM revealed higher bone-implant contact, thicker lamellar bone, and larger trabecular bone area in the PTH group than in the control group. A higher mineral apposition rate was observed in the PTH group compared to both the blank and control groups. These findings imply that intermittent administration of PTH[1-34] prevents periprosthetic osteolysis by promoting bone formation. The effects of PTH[1-34] were evaluated at a suprapharmacological dosage to the human equivalent in rats; therefore, additional studies are required to demonstrate its therapeutic potential in periprosthetic osteolysis.

PTH prevents the adverse effects of focal radiation on bone architecture in young rats

Radiation therapy is a common treatment regimen for cancer patients. However, its adverse effects on the neighboring bone could lead to fractures with a great impact on quality of life. The underlying mechanism is still elusive and there is no preventive or curative solution for this bone loss. Parathyroid hormone (PTH) is a current therapy for osteoporosis that has potent anabolic effects on bone. In this study, we found that focal radiation from frequent scans of the right tibiae in 1-month-old rats by micro-computed tomography severely decreased trabecular bone mass and deteriorated bone structure. Interestingly, PTH daily injections remarkably improved trabecular bone in the radiated tibiae with increases in trabecular number, thickness, connectivity, structure model index and stiffness, and a decrease in trabecular separation. Histomorphometric analysis revealed that radiation mainly decreased the number of osteoblasts and impaired their mineralization activity but had little effects on osteoclasts. PTH reversed these adverse effects and greatly increased bone formation to a similar level in both radiated and non-radiated bones. Furthermore, PTH protects bone marrow mesenchymal stem cells from radiation-induced damage, including a decrease in number and an increase in adipogenic differentiation. While radiation generated the same amount of free radicals in the bone marrow of vehicle-treated and PTH-treated animals, the percentage of apoptotic bone marrow cells was significantly attenuated in the PTH group. Taken together, our data demonstrate a radioprotective effect of PTH on bone structure and bone marrow and shed new light on a possible clinical application of anabolic treatment in radiotherapy.

Initial experience with teriparatide in the United States

Teriparatide has been commercially available in the United States (US) for over 3 years. This summary spans the early experience with this therapy. As of December 31, 2005, over 235 000 patients had filled a prescription for teriparatide world-wide. Data collected from July to December 2004, from 15,000 retail pharmacies in the US, indicated that the mean age of patients was 67.5 years, and more recent data collected from January through October 2005 indicated that 90% of patients were female. According to market research conducted with prescribing physicians from February through March of 2005, it is estimated that over 80% of patients receiving prescriptions for teriparatide had already experienced one or more prior fractures. Since teriparatide is administered subcutaneously, it is important that patients receive training on the use of the teriparatide injection device (i.e., the pen device). Educational programs are available for those who have been prescribed teriparatide therapy. Patients may also contact a customer care program regarding a variety of topics, including pen device use. Based on patient feedback, design changes have been implemented in the pen device to facilitate optimal use. Updates have also been made to the prescribing information to reflect the post-marketing surveillance experience. Adverse experiences reported to date have been consistent with the current product label and with cumulative teriparatide clinical trial experience. As of December 31, 2005 no reports of pathology-confirmed osteosarcoma have been received for individuals who have been treated with teriparatide, either with the commercially available drug or in clinical trials. We are unaware of any reports of osteosarcoma in association with other preparations of teriparatide, or other peptides of parathyroid hormone, either in the setting of clinical trials or from marketed drug experience.

Combination/sequential therapies for anabolic and antiresorptive skeletal agents for osteoporosis

In this paper, we focus upon the use of anabolic skeletal therapy for the treatment of postmenopausal and other forms of osteoporosis. The only anabolic skeletal agent currently available is a recombinant bioactive fragment of parathyroid hormone, PTH(1-34), known as teriparatide. The full length molecule, human PTH(1-84) is being investigated at this time as are other PTH molecules. Teriparatide improves bone quality by actions on bone turnover, bone density, bone size, and microarchitecture. In postmenopausal women with osteoporosis, teriparatide reduces the incidence for vertebral and nonvertebral fractures. In individuals who have been treated previously with an antiresorptive agent, the subsequent actions of teriparatide on bone density are delayed transiently if bone turnover is markedly suppressed. Combination therapy with teriparatide or PTH(1-84) and an antiresorptive does not appear, at this time, to offer advantages over the use of PTH or an antiresorptive alone. To maintain the gains in bone density with PTH, it is important to follow its use with an antiresorptive agent.

Teriparatide [human PTH(1-34)]: 2.5 years of experience on the use and safety of the drug for the treatment of osteoporosis

Longer survival in cystic fibrosis has led to more bone complications. One hundred thirty-six young patients were studied for 12-24 months. Low BMD was found in 66%. Fat mass and lean mass were also reduced. Impaired pulmonary function and total steroid dose had the greatest negative influence on bone.

INTRODUCTION

Low BMD is reported as a frequent complication in adult patients affected by cystic fibrosis (CF), but the available data are less consistent for younger patients.

MATERIALS AND METHODS

This study was designed to evaluate BMD longitudinally over 12-24 months in a sample of 136 young patients (3-24 years of age) and to investigate its major determinants. BMC and body composition were also evaluated.

RESULTS

BMD (expressed as Z score) of spine and of total body was reduced in 66% of patients. The prevalence of low BMD was the same in children, adolescents, and young adults. The main determinants of BMD were forced expiratory volume in 1 s (FEV1; as an index of pulmonary function), puberty, platelet count (as an index of portal hypertension), and cumulative steroid dose. Changes of FEV1 over time influenced BMD changes. Bone mass, fat mass (FM) and fat-free (lean) mass (FFM) were reduced in CF patients at both total body and subregions (trunk, limbs). Lean mass influenced BMD of total body and lower limbs, whereas fat mass (and BMI) influenced spine BMD. FEV1 also influenced FFM.

CONCLUSIONS

Low BMD was present in a significant proportion of CF patients, independent of sex and age. BMD depended on pulmonary function, steroid dose, and presence of advanced liver disease. Pulmonary function and puberty were the main stimuli for the increase of BMD over time. CF also altered body composition, and FFM was influenced by pulmonary function.