Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027627 (metastases)
 103,950 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Metastasis of breast cancer to bone occurs with advanced disease and produces substantial morbidity. Secretion of PTH-related peptide (PTHrP) from breast cancer cells is thought to play a key role in osteolytic metastases and is increased by transforming growth factor-beta (TGFbeta), which is released from resorbed bone. Elevated extracellular calcium (Ca2+(o)) also stimulates PTHrP secretion from various normal and malignant cells, an action that could potentially be mediated by the Ca2+(o)-sensing receptor (CaR) originally cloned from the parathyroid gland. Indeed, we previously showed that both normal breast ductal epithelial cells and primary breast cancers express the CaR. In this study we investigated whether the MCF-7 and MDA-MB-231 human breast cancer cell lines express the CaR and whether CaR agonists modulate PTHrP secretion. Northern blot analysis and RT-PCR revealed bona fide CaR transcripts, and immunocytochemistry and Western analysis with a specific anti-CaR antiserum demonstrated CaR protein expression in both breast cancer cell lines. Furthermore, elevated Ca2+(o) and the polycationic CaR agonists, neomycin and spermine, stimulated PTHrP secretion dose dependently, with maximal, 2.1- to 2.3-fold stimulation. In addition, pretreatment of MDA-MB-231 cells overnight with TGFbeta1 (0.2, 1, or 5 ng/ml) augmented both basal and high Ca2+-stimulated PTHrP secretion. Thus, in PTHrP-secreting breast cancers metastatic to bone, the CaR could potentially participate in a vicious cycle in which PTHrP-induced bone resorption raises the levels of Ca2+(o) and TGFbeta within the bony microenvironment, which then act in concert to evoke further PTHrP release and worsening osteolysis.
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PMID:Extracellular calcium-sensing receptor expression and its potential role in regulating parathyroid hormone-related peptide secretion in human breast cancer cell lines. 1110 43

Parathyroid carcinoma is a very rare malignancy and the least common among endocrine malignat tumors. Its etiology is still unclear and some hypotheses have been suggested: previous external radiation to the neck, pregression from benign to malignant lesion, familial hyperparathyroidism. An early accurate diagnosis is very important since surgery is the most effective therapeutic approach to parathyroid carcinoma. Prognosis is quite variable and stress is laid on the early diagnosis and radical surgery which seem to be most favorable prognostic factors. An accurate follow-up should include frequent measurements of serum calcium and PTH levels to promptly detect recurrence or metastases which are usually associated with severe hyeprcalcemia.
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PMID:Parathyroid carcinoma. A concise review. 1147 35

To examine the effect of estradiol (E(2)) without the confounding effect of hypothalamic-pituitary feedback, we studied men with prostate cancer in whom gonadotropin secretion was suppressed by LH-releasing hormone agonists (LHRH-A). Fourteen men over 65 yr of age and receiving established LHRH-A treatment (EST group) without bony metastases and 12 men who received LHRH-A as neoadjuvant therapy for locally advanced prostate cancer (NEO group) were randomized (double blind) to receive either 1 mg/d micronized E(2) (n = 12) or placebo (PL; n = 13) for 9 wk. E(2), estrone, testosterone, SHBG, PTH, and 25-hydroxy- and 1,25-dihydroxyvitamin D levels as well as markers of bone resorption [N- and C-telopeptide cross-links (NTX and CTX) and deoxypyridinoline] and bone formation (bone-specific alkaline phosphatase, osteocalcin, and N-terminal type I collagen) were measured before LHRH-A in the NEO group, before [baseline (BL)] and after 9 wk of E(2) or PL in all patients, and 6 wk after E(2) treatment in the EST group. In the NEO group, hormone levels fell 3 wk after the initial LHRH-A injection, and deoxypyridinoline increased significantly (P = 0.006). At BL, the EST group had higher bone turnover due to the longer duration of LHRH-A treatment. With E(2) treatment, E(2) levels rose into the normal male range, and two resorption markers decreased significantly from BL by 33% for NTX (P < 0.001) and 28% for CTX (P = 0.009). Bone formation markers did not change. PTH increased by 43% from BL (P < 0.01) in the E(2) group and decreased 16% from BL in the PL group (P < 0.01). Ionized calcium did not change in the E(2) group, but increased in the PL group by 2.3% (P < 0.01). NTX and CTX increased 6 wk after E(2) withdrawal in the EST group. We conclude that E(2) inhibits bone resorption in hypogonadal men through a direct skeletal effect that is independent of PTH. Low dose estrogen may be an option for the prevention and/or treatment of bone loss in this population.
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PMID:The effect of micronized estradiol on bone turnover and calciotropic hormones in older men receiving hormonal suppression therapy for prostate cancer. 1241 49

Parathyroid carcinoma is an uncommon endocrine malignancy, with difficult diagnosis. There are several presenting clinical and biochemical features that suggest it: much higher serum calcium and PTH levels than parathyroid adenomas, symptoms of severe hypercalcemia, the classical target organs affected and a palpable neck mass. Pathologic findings, local invasion, lymph node and distant metastases prove the diagnosis. Initial surgical therapy (en bloc dissection) is the only chance for cure it. The management of recurrent and/or metastatic parathyroid carcinoma is also surgical, resulting in significant palliation from hypercalcemia, whereas radiation therapy and chemotherapy are not helpful. Bisphosphonates (drugs that inhibit bone resorption) control acute and chronic hypercalcemia when surgery is not effective or possible. Preoperative localization studies (cervical ultrasound, CT scan, MRI and sestamibi scan) are useful in patients with recurrent or persistent parathyroid cancer.
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PMID:[Diagnostic-therapeutic management of parathyroid carcinoma]. 1259 36

Parathyroid carcinoma accounts for 0.5 to 4.0% of cases of primary hyperparathyroidism. The prognosis depends largely on the extent of successful resection at the time of initial operation. Therefore, early diagnosis before surgery is important. We report 3 cases of primary hyperparathyroidism. The first patient, a 20-year-old uremic female, had refractory hypercalcemia after 5 years of hemodialysis treatment. Hypercalcemia persisted despite repeated parathyroidectomy. Pathology revealed diffuse hyperplasia of the parathyroid glands with focal adenomatous changes. Multiple pulmonary metastases were found later. The second patient, a 45-year-old female with history of nephrolithiasis, presented with severe osteoporosis. She underwent repeated parathyroidectomy for local recurrence. Pathology disclosed typical features of parathyroid carcinoma with adjacent lymph node metastasis. The third patient, a 34-year-old male, had recurrent episodes of extremity fracture and hypercalcemia with palpable neck mass. He underwent resection of the parathyroid tumor. Vascular and capsular invasions were noted microscopically. All three patients were relatively young and had extremely high intact parathyroid hormone (iPTH) level (15 to 31 times the upper limit of normal). The first patient died of hypercalcemia and respiratory failure and the other 2 were treated successfully with surgical excision and, in case 2, combined chemotherapy and radiotherapy. The latter 2 patients had no recurrence during 18 months and 14 months of follow-up, respectively. Our experience with these cases suggests that the combination of the following characteristics are highly suggestive of parathyroid carcinoma: young age, palpable neck mass, concomitant renal and skeletal disease, and extremely high iPTH level in patients with PTH-dependent hypercalcemia.
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PMID:Variability of clinical presentations in three cases of parathyroid carcinoma. 1283 92

Parathyroid carcinoma is a rare cause of primary hyperparathyroidism, and the efficacy of medical therapy and chemo- and radiotherapy is poor in recurrent or metastatic disease. We report the first case of PTH immunization in which tumor shrinkage accompanied hormonal, biochemical, and clinical improvements in a patient with metastatic parathyroid carcinoma.A 50-yr-old woman with refractory parathyroid carcinoma and pulmonary metastases was immunized eight times between February 2001 and December 2003 with bovine and modified human PTH fragments and intact human PTH, mixed with Freund's adjuvant. Total and ionized calcium and PTH levels were assayed weekly for 6 months and regularly thereafter. Thoracic computed tomography scans were performed regularly. Antibodies to all PTH fragments were detected after two immunizations. Baseline PTH and total calcium were 213.0 ng/liter and 13.96 mg/dl, respectively, and remained elevated during the first three immunizations. From the fourth immunization onward, PTH and calcium decreased, and the patient's clinical condition improved markedly. PTH and calcium levels have remained controlled for more than 24 months, and the sizes (surface area) of pulmonary metastases decreased from baseline by 39-71%. This is the first evidence that PTH immunization not only can improve clinical, hormonal, and biochemical measures in parathyroid carcinoma but also has an antitumor effect.
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PMID:Hormonal and biochemical normalization and tumor shrinkage induced by anti-parathyroid hormone immunotherapy in a patient with metastatic parathyroid carcinoma. 1524 Jun 24

At the present time, tamoxifen is the most widely used anti-estrogen for adjuvant therapy and metastatic disease in postmenopausal women with breast cancer, a population at high risk for osteoporosis. This prospective study was designed to evaluate the effect of adjuvant tamoxifen on bone mineral density and all biochemical markers concomitantly in women with early-stage breast cancer in one study. Using dual-energy X-ray absorptiometry, prior to and 12 mo after tamoxifen treatment, bone mineral density in lumbar spine and femoral neck was measured in 44 women with T1-T2N0M0 estrogen-receptor-positive breast cancer receiving adjuvant treatment with tamoxifen 20 mg/d. Biomarkers that can affect bone mineral metabolism were measured before and after 3 and 12 mo of tamoxifen treatment. Bone mineral density was minimally increased in lumbar spine and femoral neck after 12 mo treatment with tamoxifen (p = 0.79 and 0.55, respectively). No differences were found in serum levels of calcium, phosphate, creatinine, ALAT, albumin, LDH, calcitonin, or estradiol. A significant decrease in osteocalcin levels was found after 3 and 12 mo (p < or = 0.01). TSH and PTH levels were increased (p < or = 0.05) after 3 mo, returning to baseline after 12 mo. In conclusion, tamoxifen has an estrogen-like effect on bone metabolism in postmenopausal women and is associated with preservation of bone mineral density in lumbar spine and femoral neck. Changes in serum concentration of biochemical markers may reflect decreased bone turnover or bone remodeling and add to the understanding of tamoxifen's effect on bone mineral density.
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PMID:Effects of tamoxifen on bone mineral density and metabolism in postmenopausal women with early-stage breast cancer. 1529 83

Parathyroid carcinoma constitutes less than 1% of primary hyperparathyroidism. The exact etiology is not known. Prior radiation to neck, chronic renal failure and genetic factors are thought to play a role. The male to female ratio is one. Parathyroid carcinomas are slow growing, have a tendency to recur locally and metastasize late. 95% of parathyroid carcinomas are functioning. The major distinguishing features of malignant hyperparathyroidism are presence of a palpable mass in the neck and features of severe hypercalcemia. By far the most important test to diagnose primary hyperparathyroidism is serum level of Immunoreactive PTH. The diagnosis of primary hyperparathyroidism is essentially clinical and biochemical. Biopsy is not necessary before definitive surgery. CT scan appears to be the best investigation for detecting the primary tumor, its local extent and metastases. Most of the symptoms are attributable to hypercalcemia, which needs to be treated aggressively. Early surgery with 'en bloc' resection of the tumor is the only potentially curative treatment. Parathyroid carcinoma is traditionally said to be resistant to radiotherapy. Various chemotherapeutic agents have been used with partial anecdotal responses. The 5-year survival is about 50% and 10-year survival varies from 13-49%.
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PMID:The carcinoma of parathyroid gland. 1531 9

Bone metastasis is a common untreatable complication associated with prostate cancer. Metastatic cells seed in skeletal sites under active turnover containing dense marrow cellularity. We hypothesized that differences in these skeletal-specific processes are among the critical factors that facilitate the preferential localization of metastatic prostate cancer in bone. To test this, athymic mice were administered PTH to induce bone turnover and increase marrow cellularity daily 1 wk before and after intracardiac inoculation of luciferase-tagged PC-3 cells. Tumor localization was monitored by bioluminescence imaging weekly for 5 wk. At the time of tumor inoculation, PTH-treated mice demonstrated significant increases in serum levels of bone turnover markers such as osteocalcin and tartrate-resistant acid phosphatase 5b and in the number of tartrate-resistant acid phosphatase-positive osteoclasts per millimeter of bone when compared with the other groups. Likewise, PTH treatment stimulated a qualitative increase in marrow cellular proliferation as determined by 5-bromo-2'-deoxyuridine immunostaining. Skeletal metastases formed in the hind limb and craniofacial regions of young mice with no difference between groups. In adult mice, however, bioluminescent signals in the hind limb and craniofacial regions were 3-fold higher in PTH-treated mice vs. controls. Fluorochrome labeling revealed increased bone formation activity in trabecular bone adjacent to tumors. When zoledronic acid, a nitrogen-containing bisphosphonate that inhibits osteoclast-mediated bone resorption, was administered concurrently with PTH, a significant reduction in the incidence of bone tumors was observed. Overall, these studies provide new evidence that skeletal sites rich in marrow cellularity under active turnover offer a more congenial microenvironment to facilitate cancer localization in the skeleton.
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PMID:Bone turnover mediates preferential localization of prostate cancer in the skeleton. 1563 91

Parathyroid cancer is a rare endocrine tumor and an uncommon cause of HPT. Advances have been made to identify a promising molecular diagnostic marker for the disease. The use of accurate preoperative imaging modalities would undoubtedly facilitate its management by making an accurate preoperative diagnosis by assessing its invasiveness, and by searching for nodal or distant metastases. The effectiveness of the application of intraoperative PTH assay in the management of this rare condition remains to be seen. Radical surgical treatment offers the best chance of cure, but for patients who have refractory unresectable disease or metastases, the availability of more effective targeted medical therapy may palliate the debilitating symptoms of hypercalcemia, reduce its metabolic complications, and potentially improve survival.
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PMID:Parathyroid cancer. 1688 98


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