Hypercalcemia of malignancy revisited

Prevalence and Etiological Profile of Hypercalcemia in Hospitalized Adult Patients and Association with Mortality

Background

The etiology of hypercalcemia varies according to the clinical setting. Hitherto, data on the prevalence and profile of hypercalcemia in hospitalized Asian-Indian patients are limited. Hence, we conducted a prospective observational study to determine the prevalence and etiological profile of hypercalcemia in hospitalized Asian-Indian patients and its association with 6-month mortality.

Materials and Methods

We conducted a prospective observational study wherein all the patients (aged >12 years) admitted to the general medicine wards of a tertiary care hospital in North India between January 1, 2016, and June 30, 2017, were screened. Finally, patients with sustained hypercalcemia (defined as corrected serum total calcium ≥10.4 mg/dl documented twice at least 24 h apart) were included in this study. These patients were followed up throughout the hospital course and thereafter till 6 months from the date of discharge.

Results

Out of 9902 patients, 150 patients had sustained hypercalcemia (prevalence 1.5%). The most common cause of hypercalcemia was malignancy (41.3%), followed by primary hyperparathyroidism (PHPT, 32.7%). Vitamin D intoxication was responsible for hypercalcemia in 8.7% of patients; 2.7% of patients had hypercalcemia of advanced chronic liver disease. Nevertheless, a definite etiology could not be identified in 7.3% of the patients with hypercalcemia. At the end of 6 months of follow-up, the cumulative mortality rate was 28%. Underlying malignancy and higher calcium levels were the significant determinants of mortality.

Conclusions

The prevalence of hypercalcemia in Asian-Indian patients admitted to a tertiary care hospital was 1.5%. The most common etiology was malignancy, followed by PHPT.

Hypercalcemia in the setting of HTLV-1 infection and a normal PTHrP level

Summary

Human T-cell lymphotropic virus-1 (HTLV-1) causes adult T-cell leukemia and lymphoma (ATLL) and is a rare but important cause of hypercalcemia. A 53-year-old male with HTLV-1-associated myelopathy presented with acute on chronic bilateral lower extremity weakness and numbness. Initial blood work revealed hypercalcemia with corrected calcium of 16.2 mg/dL (8.5-11.5) with normal levels of phosphorus and alkaline phosphatase. Workup for hypercalcemia revealed parathyroid hormone (PTH) of 14 pg/mL (10-65), 25 hydroxy vitamin D at 19.6 ng/mL (30-100), 1,25 dihydroxy vitamin D at 6.7 pg/mL (19.9-79.3), thyroid-stimulating hormone of 1.265 μIU/mL (0.5-5), undetectable PTH-related protein (PTHrP) and lactate dehydrogenase of 433 U/L (100-220). The urine calcium creatinine ratio was 0.388. Reverse transcriptase PCR was positive for HTLV-1 and negative for HTLV-2. Peripheral blood flow cytometry and lymph node biopsy confirmed ATLL. He received treatment with fluids, calcitonin and denosumab after which serum calcium levels fell (nadir: 7.7 mg/dL) and then normalized. Humoral hypercalcemia in this setting is mediated by receptor activator of nuclear factor-kappa B ligand (RANKL), PTHrP and other cytokines. PTHrP levels depend on levels of the TAX gene product, cell type and lymphocyte-specific factors. Thus, a low level, like in our patient, does not rule out HTLV-1 infection/ATLL as the cause of hypercalcemia. Hypercalcemia is known to be responsive to monoclonal antibodies against RANKL given the compound's role in mediating hypercalcemia in these cases.

Learning points

Human T-cell lymphotropic virus-1 infection and adult T-cell leukemia and lymphoma are associated with high rates of hypercalcemia and hypercalcemic crises. Hypercalcemia in these cases is mediated by osteoclastic bone resorption carried out by several agents including receptor activator of nuclear factor-kappa B ligand, parathyroid hormone-related protein (PTHrP), macrophage inflammatory protein 1 alpha, interleukins, etc. A normal PTHRrP does not rule out humoral hypercalcemia of malignancy in this setting, as indicated by this case. Hypercalcemia in such settings is highly responsive to monoclonal antibodies against RANKL given the role the ligand plays in resorptive hypercalcemia.

Prevalence of canine primary hyperparathyroidism recurrence in Keeshond and non-Keeshond dogs after curative parathyroidectomy

BACKGROUND

Primary hyperparathyroidism (PHPT) is an uncommon condition in dogs, for which there is a documented genetic predisposition in Keeshonden and sporadic cases in other breeds. Secondary literature reports a 10 per cent prevalence for recurrence in patients successfully treated by surgical parathyroidectomy, however there is no published primary literature available on which to base this assertion. This study sought to document prevalence of recurrence within Keeshonden and non-Keeshonden breeds. The authors hypothesised that Keeshonden would have a higher rate of recurrence due to the genetic predisposition for the disease, as compared with sporadic cases in other breeds, and that Keeshonden might have an earlier age of detection of disease.

METHODS

A retrospective review of medical records was undertaken to assess the prevalence of recurrence, the length of time after diagnosis that the recurrence occurred, and the age of initial diagnosis in both Keeshonden and non-Keeshonden breeds.

RESULTS

The study found that Keeshonden were significantly more likely to develop recurrence (6/12, 50 per cent) than non-Keeshonden dogs (1/15, 7 per cent) (P=0.024), and were significantly younger (median 108 v 126 months, P=0.043) at initial disease detection. Recurrence in Keeshonden occurred at median 35 months after treatment.

CONCLUSION

This suggests all dogs treated by curative parathyroidectomy for PHPT should be monitored lifelong for recurrence of disease, and that this is particularly pertinent in the Keeshond population. Earlier screening of younger, apparently healthy Keeshonden may also be advisable.

A Hospital Survey of Hypocalcemia and Hypophosphatemia in Malignancy

We evaluated the incidence of hypo- versus hypercalcemia and hypo- versus hyperphosphatemia in a survey of 158 patients with malignancy; 55/158 had bone metastases. When serum calcium levels were corrected for albuminemia, the incidence of hypo- and hypercalcemia was respectively 10.8% and 10.1 %. Hypophosphatemia was found in 29.7% patients, hyperphosphatemia in 2.5 %. The incidence was slightly different in presence of bone metastases. Hypocalcemia and hypophosphatemia prevailed In osteoblastic metastases and hypercalcemia in osteolytic metastases. The incidence of hypocalcemia and hypophosphatemia in malignancy was therefore surprisingly high, even apart from the presence of bone metastases. Both hypo- and hypercalcemia were associated with elevated serum alkaline phosphatase levels. Moreover, a calcium-phosphorus product reduction was observed in osteoblastic metastases, suggesting a condition of secondary hyperparathyroidism.

Role of Pamidronate Disodium in the Treatment of Metastatic Bone Disease

Aims and Background

Bone metastases are a common feature of advanced neoplastic disease and are considered to be among the most frequent causes of pain and complications in oncologic patients. The main objective of the treatment of such patients is to control their symptoms and improve their quality of life. Pamidronate disodium is a second-generation bisphosphonate capable of inhibiting bone resorption (particularly osteoclast activity) without affecting bone reminerali-zation. After a brief introduction concerning the pathophysiology of bone metastases and neoplastic bone pain, we herein present data on the clinical pharmacology and toxicity of bisphosphonates in general, and pamidronate in particular. We conclude by reviewing the literature on the use of pamidronate in phase II and III trials involving patients with metastatic bone disease.

Methods

The paper is based on a review of articles published between 1984 and 1997 selected from the Cancerline and Medline databases.

Results

In the considered phase II and III studies involving patients with bone metastases (breast cancer and multiple myeloma in particular), pamidronate proved to be efficacious in reducing the incidence of pain and skeletal complications, decreasing the excretion of metabolic markers of bone resorption and improving the quality of life. Intravenous infusions of 60-90 mg over a period of 2 hr every 3-4 weeks did not cause any significant toxic effects and was easily managed.

Conclusions

Pamidronate is a bisphosphonate that is efficacious in the treatment of symptomatic bone metastases and can be considered an important therapeutic option in association with systemic treatments, radiotherapy and normal supportive care, especially in patients with breast cancer and multiple myeloma. Further randomized studies are necessary to confirm the positive preliminary results in other neoplasms, analyze the cost/benefit ratio of the treatment, and verify the possibility that, in addition to being used for palliative purposes, pamidronate may also prevent or delay the appearance of bone metastases.

Effect of Prophylactic Calcitriol Administration on Serum Ionized Calcium Concentrations after Parathyroidectomy: 78 Cases (2005-2015)

Background

Prophylactic administration of calcitriol has been suggested to mitigate the risk of hypocalcemia after parathyroidectomy. The effect of calcitriol on postoperative serum ionized calcium concentrations has not been evaluated in dogs after parathyroidectomy.

Hypothesis/Objectives

To determine the effect of prophylactic calcitriol administration on postoperative serum ionized calcium (iCa) concentrations in dogs with primary hyperthyroidism (PHPTH) treated by parathyroidectomy.

Animals

Seventy‐eight dogs with primary hyperparathyroidism treated surgically.

Methods

Multi‐institutional retrospective case study. Medical records from 2005 to 2015 were evaluated. Dogs were included if they had a diagnosis of PHPTH and had surgery to remove parathyroid tissue. Serum iCa concentrations were monitored for a minimum of 2 days postoperatively. Two study groups were evaluated: calcitriol administration and no calcitriol administration.

Results

Serial postoperative iCa concentrations measured at 12‐hour time intervals for 2 days postoperatively were positively associated with preoperative iCa concentrations. This association was evident at each time interval, and the effect of preoperative iCa concentrations on postoperative iCa concentrations decreased as time elapsed (12 hours, P < 0.0001; 24 hours, P < 0.0001; 36 hours, P < 0.04; and 48 hours, P = 0.01). Prophylactic calcitriol administration was not found to be significantly associated with postoperative iCa concentrations or its rate of decrease after parathyroidectomy.

Conclusion and Clinical Importance

We found no protective value in administering calcitriol prophylactically to prevent hypocalcemia in the immediate postoperative period (48 hours) after parathyroidectomy. Preoperative iCa concentrations had a significant positive association with postoperative iCa concentrations throughout the monitoring period.

[Diagnostic approach and management of hypercalcaemia in dogs exemplary of primary hyperparathyroidism]

Hypercalcaemia can be caused by many different diseases. This article summarizes the causes, pathophysiologic mechanisms and diagnostic procedures as well as treatment recommendations. The main focus is on hypercalcaemia in primary hyperparathyroidism (PH), complemented by a case report. An elevated total calcium level should generally be investigated and verified by measurement of ionized calcium concentration. The further diagnostic approach depends on the phosphate level. Tumour screening, measurement of parathormone and parathromone-related protein and sonography of parathyroid glands may be necessary. If the calcium-phosphate-product exceeds 60 mg/dl, there is a risk of tissue mineralisation and a rapid treatment of hypercalcaemia is required. For acute therapy, sodium chloride infusion, furosemide and glucocorticoids can be used. Glucocorticoids should only be given after strict indication and after a definite diagnosis. For long-term management, bisphosphates, particularly alendronate, are increasingly used successfully. Causal therapy of PH can be performed by parathyreoidectomy, heat ablation or ethanol ablation. Thereafter, particularly in cases of severe preoperative hypercalcaemia, hypocalcaemia can occur. Treatment is performed using vitamin D₃ (calcitriol), which may also be given preoperatively in cases of severe hypercalcaemia. A concomitant oral calcium supplementation using calcium carbonate as medication of choice is contentious. Due to a potential relapse after successful excision of the affected parathyroid gland in PH, the serum calcium level should be monitored periodically.

Hypercalcemia of advanced chronic liver disease: a forgotten clinical entity!

Hypercalcemia caused by advanced chronic liver disease (CLD) without hepatic neoplasia is uncommonly reported and poorly understood condition. We are reporting two cases of advanced CLD who developed hypercalcemia in the course of the disease. This diagnosis of exclusion was made only after meticulous ruling out of all causes of hypercalcemia. The unique feature of this type of hypercalcemia is its transient nature that may or may not require treatment. This clinical condition in patients with CLD should be kept in mind while evaluating the cause of hypercalcemia in them.

A laboratory prognostic index model for patients with advanced non-small cell lung cancer

Purpose

We aimed to establish a laboratory prognostic index (LPI) in advanced non-small cell lung cancer (NSCLC) patients based on hematologic and biochemical parameters and to analyze the predictive value of LPI on NSCLC survival.

Patients and Methods

The study retrospectively reviewed 462 patients with advanced NSCLC diagnosed between 2000 and 2010 in a single institution. We developed an LPI that included serum levels of white blood cells (WBC), lactate dehydrogenase (LDH), albumin, calcium, and alkaline phosphatase (ALP), based on the results of a Cox regression analysis. The patients were classified into 3 LPI groups as follows: LPI 0: normal; LPI 1: one abnormal laboratory finding; and LPI 2: at least 2 abnormal laboratory findings.

Results

The median follow up period was 44 months; the median overall survival (OS) and median progression-free survival (PFS) were 11 and 6 months, respectively. A multivariate analysis revealed that the following could be used as independent prognostic factors: an Eastern Cooperative Oncology Group performance status score (ECOG PS) ≥2, a high LDH level, serum albumin <3 g/dL, serum calcium>10.5 g/dL, number of metastases>2, presence of liver metastases, malignant pleural effusion, or receiving chemotherapy ≥4 cycles. The 1-year OS rates according to LPI 0, LPI 1, and LPI 2 were 54%, 34%, and 17% (p<0.001), respectively and 6-month PFS rates were 44%, 27%, and 15% (p<0.001), respectively. The LPI was a significant predictor for OS (Hazard Ratio (HR): 1.41; 1.05–1.88, p<0.001) and PFS (HR: 1.48; 1.14–1.93, p<0.001).

Conclusion

An LPI is an inexpensive, easily accessible and independent prognostic index for advanced NSCLC and may be helpful in making individualized treatment plans and predicting survival rates when combined with clinical parameters.

Immunolocalization of PTHrP in the parotid glands of three rodents species: Clethrionomys glareoulus, Microtus arvalis and white Swiss mice

The current study was inspired by the fact that since 2004 no report had appeared on the occurrence of this peptide in healthy parotid glands of humans and animals. The objective of the current study was to investigate the immunolocalization of PTHrP in the parotid gland of three male rodents: 6 common voles (Microtus arvalis, Pallas, 1779), 6 bank voles (Clethrionomys glareoulus, Schreber, 1780) and 6 white Swiss mice, as well as to find out any species differences in the distribution of this peptide in various types of cells of the parotid gland. Immunocytochemical reactions were performed using the ABC technique with specific rabbit antibodies against human PTHrP (34-53) (CALBIOCHEM), diluted 1:70 and 1:50. We observed positive PTHrP expression in the epithelial cells of the striated duct in all the three animal species. The expression was strong in white mouse and very strong in common vole and bank vole. In all the rodent species studied, the reaction for PTHrP was granular in nature and irregularly distributed in the cytoplasm, being definitely stronger at the base and weaker at the apex of the cells. The PTHrP expression was negative in the epithelium of the intercalated duct, interlobular duct, main excretory duct, as well as in the myoepithelial cells surrounding the excretory ducts or serous acini.

Rat model of the hypercalcaemia induced by parathyroid hormone-related protein: characteristics of three bisphosphonates

In our preliminary experiment, we found that a constant infusion of a high dose of parathyroid hormone-related protein induced both hyperphosphataemia and hypocalcaemia, secondary to renal dysfunction. Therefore, in this study, we developed two types of parathyroid hormone-related protein-induced hypercalcaemia models. One is the hypercalcaemia model, which did not show renal-dysfunction-induced hypocalcaemia. This model might be suitable for estimating hypocalcaemic activities of drugs, especially of those that act on bone resorption. The other is the model for estimating histological changes, which is associated with renal dysfunction. We then used these models to investigate the effects of three different bisphosphonates. Since the hypercalcaemic effect of parathyroid hormone-related protein infusion plateaued at 20 pmol/h, and higher doses of parathyroid hormone-related protein caused an elevation of blood urea nitrogen, the parathyroid hormone-related protein infusion rate was fixed at 20 pmol/h to avoid renal dysfunction and at 40 pmol/h to elicit renal dysfunction. The hypocalcaemic efficiencies of clodronate and etidronate were almost the same but pamidronate was 17.9 times more potent than clodronate. Additionally, both clodronate and pamidronate decreased the plasma concentrations of blood urea nitrogen and the Ca2+ times inorganic P product, whereas etidronate lacked these effects. Clodronate suppressed renal calcification and tubular dilatation in the renal-dysfunction model. These data indicated that clodronate and pamidronate not only decrease the plasma Ca2+ concentration but also improve the renal dysfunction induced by hypercalcaemia.

Hypercalcemic hypocalciuria: a critical differential diagnosis for hyperparathyroidism

A differential diagnosis for hyperparathyroidism includes all causes of hypercalcemia; the primary causes of which are primary hyperparathyroidism and humoral hypercalcemia of malignancy. Benign familial hypocalciuric hypercalcemia is a rare condition of primary importance because failure to recognize this entity leads to unnecessary surgery. There are a plethora of other rare causes of hypercalcemia that can be distinguished from primary hyperparathyroidism by history and laboratory profiles. This article discusses the main and less common causes of hypercalcemia and provides guidance for distinguishing among them.

Native osteoprotegerin gene transfer inhibits the development of murine osteolytic bone disease induced by tumor xenografts

OBJECTIVE

Multiple myeloma is a plasma cell malignancy characterized by the development of osteolytic lesions leading to bone pain, pathologic fractures, and hypercalcemia. Osteoprotegerin (OPG) is a potent inhibitor of osteoclast differentiation and activation, but is limited as a therapeutic agent due to its short circulating half-life. In order to overcome these limitations, the therapeutic effects of native OPG gene transfer are examined.

MATERIALS AND METHODS

We used replication-incompetent lentiviral vectors to transfer the unmodified, native human OPG gene ex vivo into human ARH-77 cells injected into severe combined immunodeficient (SCID) mice, to determine gene transfer efficiency as well as the impact on disease progression in this in vivo model.

RESULTS

We can efficiently transfer and express either the LacZ marker gene or the native human OPG gene into human ARH-77 cells. Moreover, transfer of the OPG gene into ARH-77 cells reduces the development of osteolytic bony lesions when these cells are injected into SCID mice, compared to mice injected with either unmodified ARH-77 cells or ARH-77 cells transduced with the OPG gene in the antisense orientation. This therapeutic effect was manifested as a reduction in vertebral compression deformities and in the number and size of long-bone osteolytic lesions on skeletal radiographs, as well as a decrease in osteoclast surface on histologic analysis.

CONCLUSIONS

A lentiviral vector can efficiently transfer the native human OPG gene to myeloma cells ex vivo and inhibit myeloma-induced bone destruction, thereby suggesting a therapeutic potential for unmodified, native OPG gene transfer for osteoclast-dependent skeletal disorders.

Hypercalcemic complication in patients with oral squamous cell carcinoma

Hypercalcemia is one of the metabolic complications associated with cancer. To assess the frequency of hypercalcemia in patients with squamous cell carcinoma (SCC), 242 patients who were evaluated as having SCC in the oral cavity between July 1995 and June 2001 were investigated. All patients were periodically monitored for their serum level of calcium (Ca). Hypercalcemia was defined as a serum Ca concentration higher than 11 mg/dl. By this definition, hypercalcemia was detected in 12 of the 242 patients (5.0%). All 12 patients were at an advanced stage of oral SCC. In these 12 patients, the serum level of parathyroid hormone-related protein (PTH-rP) was also significantly elevated. Therefore, we diagnosed these diseases as humoral hypercalcemia of malignancy (HHM). Moreover, we studied the efficacy of anti-hypercalcemic therapy on the quality of life (QOL). The European Organization for Research and Treatment of Cancer (EORTC) QLQ-C30 was used for estimation of QOL. The patients with HHM who were administrated drugs such as bisphosphonate and calcitonin showed a reduction in their Ca and PTH-rP levels, and the six of ten EORTC QLQ-C30 subscales (emotional functioning, cognitive functioning, fatigue, dyspnoea, nausea/vomiting and appetite loss) were also improved after the anti-hypercalcemic therapy. However, these suppressive effects were temporary. The median survival time after the diagnosis of HHM was only 54.9+/-18.3 days (range 27-86 days). Therefore, HHM in SCC appears to be an ominous prognostic sign. Although anti-hypercalcemic therapy has a palliative role, the patients may be in less discomfort during the terminal stage of their illness.

Bone marrow micrometastasis in breast cancer

BACKGROUND

Several studies have demonstrated that bone marrow micrometastasis in patients with breast cancer is an independent prognostic factor for systemic recurrence and poorer survival.

METHODS

This review describes the detection and clinical significance of micrometastatic cells in bone marrow, and examines the correlation between such micrometastasis and established clinicopathological prognostic factors. The relevant English language literature on bone marrow micrometastasis in breast cancer was searched via Medline (1975-2002), cross-referencing with key articles on the subject.

RESULTS AND CONCLUSION

The balance of evidence favours the hypothesis that bone marrow micrometastasis impacts on disease-free and overall survival. Further prospective studies are required to examine this in greater detail, with particular reference to early node-negative breast cancer and the value of adjuvant systemic therapy in patients with bone marrow micrometastasis.

Bisphosphonates: biological response modifiers in breast cancer

Bone recurrence constitutes one third of initial sites of relapse and one half of distant sites of relapse at 10 years from diagnosis of breast cancer. Bone pain, fracture (including vertebral fracture resulting from increased bone resorption following chemotherapy-induced menopause), and hypercalcemia are components of skeletal morbidity. The pathophysiology of malignant osteopathy occurs because of the secretion of substances (such as parathyroid hormone-related peptide), by the malignant cell, which stimulate osteoclast function; this in turn feeds further growth, which causes a vicious cycle. Interruption of this cycle by bisphosphonates may inhibit the growth of malignant cells. Bisphosphonates are drugs that inhibit bone turnover by decreasing bone resorption. Side effects of bisphosphonates include upper gastrointestinal symptoms (in oral nitrogen-containing bisphosphonates) and diarrhea (in oral non-nitrogen-containing bisphosphonates) and an acute phase-like reaction with intravenous (I.V.) pamidronate. Bisphosphonates have different molecular mechanisms of action: Nitrogen-containing bisphosphonates (eg, pamidronate and alendronate) inhibit the mevalonate-signaling pathway while the non-nitrogen-containing drugs (eg, clodronate) incorporate into adenosine triphosphate analogues. There is in vitro evidence that these drugs also possess anticancer properties. In hypercalcemia patients, treatment with pamidronate and zoledronate produce prompt and efficient normocalcemia. Intravenous pamidronate and zoledronate, oral clodronate, and ibandronate reduce skeletal complications in patients with bone metastases; I.V. pamidronate and clodronate are useful for bone pain relief. Three adjuvant bisphosphonate trials are discussed herein: 2 small open-label studies giving conflicting results and a large placebo-controlled trial of oral clodronate. This latter trial shows a reduction in the incidence of skeletal metastases (while the patients are on therapy) and an improved survival at 5 years.

Malignant bone pain: pathophysiology and treatments

Metastatic involvement of the bone is one of the most frequent causes of pain in cancer patients and represents one of the first signs of widespread neoplastic disease. The pain may originate directly from the bone, from nerve root compression, or from muscle spasms in the area of the lesions. The mechanism of metastatic bone pain is mainly somatic (nociceptive), even though, in some cases, neuropathic and visceral stimulations may overlap. The conventional symptomatic treatment of metastatic bone pain requires the use of multidisciplinary therapies, such as radiotherapy, in association with systemic treatment (hormonotherapy, chemotherapy, radioisotopes) with the support of analgesic therapy. Recently, studies have indicated the use of bisphosphonates in the treatment of pain and in the prevention of skeletal complications in patients with metastatic bone disease. In some patients, pharmacologic treatment, radiotherapy, and radioisotopes administered alone or in association are not able to manage pain adequately. The role of neuroinvasive techniques in treating metastatic bone pain is debated. The clinical conditions of the patient, his life expectancy, and quality of life must guide the physician in the choice of the best possible therapy.

The possible role of locally produced cytokines in the pathogenesis of peritrochanteric fractures in the elderly

Sixteen patients with intertrochanteric femoral fractures were studied for possible involvement of the cytokines interleukin-6 (IL-6), interleukin-1 beta (IL-1beta), tumor necrosis factor-alpha, and the disease activity factors C-reactive protein and alpha1-antitrypsin as local bone-resorbing agents. Cytokine and disease activity factor levels were measured in gluteus medius muscle and serum samples and were compared to sera obtained from age- and sex-matched healthy controls. Interleukin-6 and IL-1beta levels were significantly higher (P=.0024 and P=.036, respectively) in the muscle samples from the fractured side than in the samples from the contralateral unaffected side. Levels of IL-6 and IL-1beta also were significantly higher in patients' sera than in the sera of healthy controls. These results support a new hypothesis that may contribute to the pathogenesis of fractures in the elderly: unilaterally locally over-produced IL-6 and IL-1beta may lead to local bone resorption in the intertrochanteric region, which subsequently weakens the femoral bone and increases the risk of unilateral peritrochanteric fractures.

Increased prevalence of primary hyperparathyroidism in treated breast cancer

Hypercalcemia occurring in patients with advanced breast cancer (BC) is generally due to osteolytic metastases or to the activity of circulating tumor-derived products. In these conditions, the production of endogenous PTH is reduced. The frequency of hypercalcemia due to primary hyperparathyroidism in breast cancer is unknown. We examined the occurrence of primary hyperparathyroidism in a large group of women with treated BC. A total of 100 consecutive women aged 28-80 years with treated breast cancer were enrolled. One hundred and two healthy age-matched women and 60 age-matched female patients with differentiated thyroid carcinoma examined before thyroidectomy were used as controls. Intact serum PTH and serum calcium were measured in all patients and controls. Hypercalcemia associated with elevated serum PTH concentration indicating primary hyperparathyroidism was found in 7 BC patients (7%) and in none of healthy women or patients with thyroid cancer. The pre-operative staging of BC patients with primary hyperparathyroidism was I in six and II in one of them, and no patient had evidence of distant metastases. A parathyroid adenoma was found in all 6 BC patients submitted to neck exploration, one patient refused surgery. Serum calcium and PTH concentrations returned to normal levels after surgery. Two BC patients had increased serum PTH and normal calcium concentrations. One of them had low serum 25-hydroxyvitamin D [25(OH)D]. One patient with spread bone metastases had neoplastic hypercalcemia with undetectable serum PTH concentration. All remaining 90 BC patients had serum calcium and PTH concentrations within normal limits, but their mean (+/-SD) values (9.6+/-0.5 mg/dl for serum calcium, 38.0+/-16.4 mg/dl for serum PTH ) were slightly but significantly greater than in normal controls (9.3+/-0.5 mg/dl, p=0.003 and 27.9+/-10.6 pg/ml, p=0.0001, respectively) and in patients with thyroid cancer (9.2+/-0.6 mg/dl, p=0.001 and 26.2+/-11.0 pg/ml, p=0.001), with no relationship with clinical staging or anti-tumor therapy.

IN CONCLUSION

1) an increased frequency of parathyroid adenoma was found in BC patients with mildly aggressive neoplastic disease; 2) in BC patients with no evidence of primary hyperparathyroidism mean serum PTH and calcium concentrations were significantly greater than in healthy controls and in patients with thyroid carcinoma; and 3) this finding was unrelated to clinical staging or anti-tumor therapy. Thus, primary hyperparathyroidism should be considered as a possible cause of hypercalcemia in patients with non-aggressive breast cancer. We suggest that serum PTH should be determined in all BC patients with increased serum calcium concentration, especially in those with no evidence of metastatic disease.

The potential role of bisphosphonates as adjuvant therapy in the prevention of bone metastases

BACKGROUND

Bisphosphonates (BPs) reduce bone resorption rates by inhibiting osteoclast function, although direct antineoplastic effects and poorly understood effects on bone pain also may occur. Within the family of BPs there are more similarities in pharmacologic effects than differences, although side effect profiles, rates of oral absorption, and potency do differ. Oral clodronate and intravenous pamidronate reduce skeletal complications in patients with bone metastases from breast carcinoma (as well as in myeloma). Uncontrolled trials of prostate carcinoma also suggest clinical benefit.

METHODS

Animal studies show that BPs can reduce the rate of development of bone metastases (for example, in Walker 256 carcinoma), but there is little evidence of an effect at nonosseous sites. The hypothesis that the growth of subclinical osseous metastases is augmented by products of bone resorption (a "vicious cycle") and may be diminished by a local reduction of these substances has led to trials of BPs involving patients with no clinical evidence of bone metastases. These trials are critically assessed in this review.

RESULTS

In patients with recurrent breast carcinoma but no overt bone metastases, oral clodronate reduced the number of diagnosed bone metastases; but the number of patients who had relapses in bone, though smaller, was not significantly different from the number among patients who took placebo. In a trial of oral pamidronate, no effect was seen, but compliance was a problem because of gastrointestinal side effects. Patients treated for operable breast carcinoma have four or five times the normal rate of vertebral fracture, and BPs do reduce the rate of bone loss. Three adjuvant clodronate trials have been reported. The first, an open-label controlled trial (Diel et al.), showed a reduction in osseous and nonosseous recurrences and an increase in disease free and overall survival with 2 years of clodronate. A second open-label trial (Saarto et al.) of similar size involving lymph node positive breast carcinoma patients showed no effect on the rate of bone metastasis relapse and a deleterious effect on relapse rates of nonosseous metastases with 3 years of clodronate. A third placebo-controlled trial involving 1079 patients reported, in an interim analysis, a reduction in osseous metastases during treatment with 2 years of clodronate, but no effect on nonosseous metastases or survival.

CONCLUSIONS

A confirmatory clinical trial is required for two interrelated reasons: 1) scientifically, it is important to demonstrate that an agent that has its dominant effect on a normal tissue cell, the osteoclast, can influence the growth of neoplastic cells; and 2) from the perspective of patient care, it must be unequivocally shown that a reduction in the rate of osseous recurrence translates into an improvement in disease free survival or an improvement in quality of life through reduction of adverse skeletal events. The National Surgical Adjuvant Breast Project has committed to conducting this study and including women with operable breast carcinoma.

Neurochemical and cellular reorganization of the spinal cord in a murine model of bone cancer pain

The cancer-related event that is most disruptive to the cancer patient's quality of life is pain. To begin to define the mechanisms that give rise to cancer pain, we examined the neurochemical changes that occur in the spinal cord and associated dorsal root ganglia in a murine model of bone cancer. Twenty-one days after intramedullary injection of osteolytic sarcoma cells into the femur, there was extensive bone destruction and invasion of the tumor into the periosteum, similar to that found in patients with osteolytic bone cancer. In the spinal cord, ipsilateral to the cancerous bone, there was a massive astrocyte hypertrophy without neuronal loss, an expression of dynorphin and c-Fos protein in neurons in the deep laminae of the dorsal horn. Additionally, normally non-noxious palpation of the bone with cancer induced behaviors indicative of pain, the internalization of the substance P receptor, and c-Fos expression in lamina I neurons. The alterations in the neurochemistry of the spinal cord and the sensitization of primary afferents were positively correlated with the extent of bone destruction and the growth of the tumor. This "neurochemical signature" of bone cancer pain appears unique when compared to changes that occur in persistent inflammatory or neuropathic pain states. Understanding the mechanisms by which the cancer cells induce this neurochemical reorganization may provide insight into peripheral factors that drive spinal cord plasticity and in the development of more effective treatments for cancer pain.

Neurochemical and cellular reorganization of the spinal cord in a murine model of bone cancer pain

The cancer-related event that is most disruptive to the cancer patient's quality of life is pain. To begin to define the mechanisms that give rise to cancer pain, we examined the neurochemical changes that occur in the spinal cord and associated dorsal root ganglia in a murine model of bone cancer. Twenty-one days after intramedullary injection of osteolytic sarcoma cells into the femur, there was extensive bone destruction and invasion of the tumor into the periosteum, similar to that found in patients with osteolytic bone cancer. In the spinal cord, ipsilateral to the cancerous bone, there was a massive astrocyte hypertrophy without neuronal loss, an expression of dynorphin and c-Fos protein in neurons in the deep laminae of the dorsal horn. Additionally, normally non-noxious palpation of the bone with cancer induced behaviors indicative of pain, the internalization of the substance P receptor, and c-Fos expression in lamina I neurons. The alterations in the neurochemistry of the spinal cord and the sensitization of primary afferents were positively correlated with the extent of bone destruction and the growth of the tumor. This "neurochemical signature" of bone cancer pain appears unique when compared to changes that occur in persistent inflammatory or neuropathic pain states. Understanding the mechanisms by which the cancer cells induce this neurochemical reorganization may provide insight into peripheral factors that drive spinal cord plasticity and in the development of more effective treatments for cancer pain.

Lamotrigine-associated anticonvulsant hypersensitivity syndrome

We systematically reviewed and analyzed published and unpublished cases of lamotrigine-associated adverse drug reactions consistent with the features of the anticonvulsant hypersensitivity syndrome (AHS) to identify characteristics of the syndrome. We identified 26 cases (mean age, 28+/-18 years; range, 3.5 to 74 years; 54% female), of which nine were published. The characteristics of the syndrome associated with lamotrigine are comparable to AHS induced by older aromatic anticonvulsants.

Role of interleukin-6 in uncoupling of bone in vivo in a human squamous carcinoma coproducing parathyroid hormone-related peptide and interleukin-6

OCC tumor has been established from a human squamous carcinoma associated with humoral hypercalcemia of malignancy (HHM) and shown to overproduce parathyroid hormone-related peptide (PTHrP) and cause aggressive hypercalcemia when implanted into nude rats. In the present study, we have demonstrated by reverse transcription-polymerase chain reaction and Northern blot analysis that OCC tumor also overexpressed interleukin 6 (IL-6) mRNA and that tumor-bearing animals exhibited a marked increase in plasma IL-6 as well as PTHrP concentrations. When a monoclonal antibody against human IL-6 was injected to block the activities of tumor-derived IL-6, bone loss in tumor-bearing animals was significantly prevented. Quantitative bone histomorphometric analysis revealed that treatment with anti-IL-6 antibody caused a substantial decrease in both osteoclast number and eroded surface (as parameters of bone resorption) and also a significant increase in the mineral apposition rate, but little effect on the osteoblastic surface. These results provide in vivo evidence suggesting that in tumors coproducing IL-6 and PTHrP, IL-6 is involved not only in the acceleration of osteoclastic bone resorption but also, at least in part, in the suppression of osteoblastic functions in HHM syndrome.

Bone Resorption in Multiple Myeloma and in Monoclonal Gammopathy of Undetermined Significance: Quantification by Urinary Pyridinium Cross-Links of Collagen

To quantify osseous breakdown in multiple myeloma (MM), monoclonal gammopathy of undetermined significance (MGUS), and benign osteoporosis, we measured urinary levels of pyridinium cross-links of collagen in 50 patients with newly diagnosed and untreated MM, 40 patients with MGUS, 40 untreated patients with osteoporotic vertebral fractures, and 64 healthy adults. Ion-paired, reverse-phase high-performance liquid chromatography (HPLC) was used to measure total urinary excretion of pyridinoline (h-PYD) and deoxypyridinoline (h-DPD). Urinary excretion of free immunoreactive deoxypyridinoline (i-DPD) was determined with an enzyme immunoassay. MM patients had significantly (P < .0001) higher levels of h-PYD, h-DPD, and i-DPD than the healthy adults, patients with MGUS, or patients with osteoporosis. The MGUS and osteoporosis groups presented with elevated (P < .05) levels of urinary pyridinium cross-links when compared with healthy controls. In 20 MM patients who subsequently received chemotherapy, the percent changes in i-DPD did not correlate with the changes in the monoclonal protein. In one of three patients experiencing a transition of initial MGUS into stage I MM, i-DPD increased above the upper limit of the normal range. In 13 patients with stable MGUS, i-DPD remained normal in repeated measurements. Based on the upper limits of the normal range, the sensitivity of urinary pyridinium cross-links in stage I and II MM was low (<50%), but it was between 78% (h-DPD) and 93% (i-DPD) in stage III MM. Specificity in patients with MGUS was between 87% (h-PYD) and 97% (h-DPD). In conclusion, determining the urinary excretion of pyridinium cross-links seems to be a promising noninvasive and thus easily repeatable method for evaluating the actual degree of osseous breakdown. Although measurement of pyridinium cross-link levels is not useful in discriminating patients with MGUS from early-stage myeloma patients, determination of i-DPD levels may contribute importantly to clinical guidance, since increased i-DPD levels seem to identify patients who are particularly likely to benefit from osteoclast-inhibiting drugs such as bisphosphonates. The fact that in a number of patients paraprotein concentrations and i-DPD levels did not change in parallel but instead diverged strongly after chemotherapy might explain the observation that bone lesions sometimes progress even in patients who achieve complete remission.

Multiorgan dysfunction and disseminated intravascular coagulation in children receiving lamotrigine and valproic acid

Two children developed multiorgan dysfunction with disseminated intravascular coagulation 9 days after lamotrigine was added to their antiepileptic therapy, which included valproic acid. During the episodes, rhabdomyolysis was detected in one of them, while being seizure-free, suggesting that this adverse reaction may involve muscular tissue.

Binding and cyclic AMP stimulation by N-terminally deleted human PTHs (3-84 and 4-84) in a homologous ligand receptor system

We have produced in yeast two human parathyroid hormone (hPTH) analogs with amino-terminal deletions, hPTH(3-84) and hPTH(4-84), employing the mating factor alpha (MF alpha) expression system. The authenticity of the polypeptides was demonstrated by amino-terminal analysis, amino acid composition, and molecular mass analysis. In cells (LLC-PK1) transfected with the human PTH/parathyroid hormone-related protein (PTHrP) receptor, using [125I-Tyr36]chickenPTHrP(1-36)NH2 as radioligand, binding studies revealed dissociation constants at equilibrium (Kd) for hPTH(3-84) and hPTH(4-84) of 4.7 and 8.0 nM, respectively, only slightly higher than natural recombinant hPTH(1-84) Kd = 2.3 nM). In comparison, [Nle8,18,Tyr34]bovinePTH(3-34)NH2 and [Tyr36]cPTHrP(1-36)NH2 showed equal Kd's of 1.9 nM. Neither of the N-terminally deleted hPTH analogs showed any detectable stimulation of cAMP production in the cells at concentrations below 20 nM. At supersaturated concentrations (500 nM) with receptor occupancy of more than 95% these hPTH analogs revealed about 15% rest agonism compared with that of hPTH(1-84). hPTH(1-84) and [Tyr36]cPTHrP(1-36)NH2 showed an equal half maximal cyclic adenosine monophosphate (cAMP) stimulation of about 0.8 and 0.7 nM, respectively. The hPTH analogs did not show any ability to antagonize cellular cAMP production induced by either hPTH or [Tyr36]cPTHrP(1-36)NH2. [Nle8,18,Tyr34]bPTH(3-34)NH2 did also not antagonize cAMP stimulation by hPTH, but inhibited [Tyr36]cPTHrP(1-36)NH2-induced cAMP production by 40% when present at a 1000 M excess. These distinct results related to PTH and PTHrP from different species are important to consider in experiments evaluating potential hPTH or PTHrP antagonism, and employment of a hPTH/PTHrP receptor model is a requirement.

Primary hyperparathyroidism in two cats

Primary hyperparathyroidism (PHP) is an infrequently diagnosed disorder in cats. In this report the signs and symptoms of two cats with hypercalcaemia due to PHP are described, together with diagnostic approach, results of treatment, and immunohistochemical findings. A 9-year-old and a 13-year-old neutered male domestic shorthair cat were presented with signs of lethargy, anorexia, and vomiting. Both cats had persistent hypercalcaemia and normo- to hypophosphataemia. Cytological examination of a fine-needle aspiration biopsy sample of a palpable cervical mass revealed groups of benign glandular-epithelial cells in one cat. In the other cat no cervical mass was palpable. In this cat plasma parathyroid hormone (PTH) levels were measured repeatedly and these values exceeded the maximum reference value on two occasions. Following exclusion of other causes of hypercalcaemia both cats were subjected to neck surgery and in both a solitary parathyroid adenoma was removed. The adenomas contained an abundance of PTH, as demonstrated by immunohistochemical techniques. Plasma calcium and phosphate concentrations returned to within, reference ranges postoperatively. Recovery was uncomplicated and there were no signs of recurrence on follow-up examinations.

Utility of bisphosphonates in treating bone metastases

Bone is the most common site of metastases from breast and prostate cancer, and bone destruction is characteristic of multiple myeloma. Increased osteoclast activity plays a key role in cancer-induced bone destruction. Bisphosphonates reduce osteoclastic bone resorption through various mechanisms as yet not fully elucidated. Bisphosphonates have proven to be effective in the treatment of tumor-induced hypercalcaemia. Several clinical trials indicated that these compounds can positively influence many aspects of neoplastic bone disease, however, many questions regarding their long-term efficacy and optimal therapeutic schedule await clarification from well-designed clinical trials.

Hypercalcemia in a patient with chronic lymphocytic leukemia evolving into Richter's syndrome

Hypercalcemia is a rare complication of chronic lymphocytic leukemia (CLL), mostly seen in the context of advanced disease, for which different pathogenetic mechanisms have been postulated. A CLL patient who developed hypercalcemia in the setting of Richter's syndrome is reported. She was a 69-year old woman with stage B (II) CLL of 28-month duration, who presented with mental confusion, anorexia, vomiting, and diffuse bone pain, with hypercalcemia being subsequently found. A lymph node biopsy demonstrated evolution of CLL into Richter's syndrome. Serum levels of parathyroid hormone (PTH), PTH-related peptide and several cytokines were normal. The hypercalcemia initially responded to conventional treatment and chemotherapy, but it reappeared coincidentally with disease progression and the development of osteolytic lesions. Richter's syndrome should be kept in mind in CLL patients with hypercalcemia.

Parathyroid hormone related protein and interleukin-6 mRNA expression in larynx and renal cell carcinomas from normocalcaemic and hypercalcaemic patients

AIMS

To determine the expression of parathyroid hormone related protein (PTHrP) and interleukin-6 (IL-6) mRNAs and their possible relation in malignant tumours, derived from patients with and without hypercalcaemia, commonly associated with humoral hypercalcaemia of malignancy.

METHODS

PTHrP and IL-6 mRNA expression was studied by northern blot analysis in tumour specimens from 13 consecutive patients. Six patients (two with hypercalcaemia) had squamous cell carcinomas of the larynx and seven (one with hypercalcaemia) had renal cell carcinomas.

RESULTS

There was no relation between the histological features of the tumours and the expression of either PTHrP or IL-6 mRNAs. PTHrP mRNA was detected in all squamous cell carcinomas, expression being highest in the two patients with hypercalcaemia. In the renal cell carcinomas PTHrP mRNA was expressed only in the patient with hypercalcaemia. IL-6 mRNA was detected in nearly all tumours studied but there was no apparent relation between its expression and that of PTHrP mRNA or serum calcium concentrations.

CONCLUSIONS

PTHrP mRNA expression is increased in patients with hypercalcaemia but is not related to IL-6 mRNA expression. The results suggest a quantitative relation between PTHrP gene expression and hypercalcaemia, and imply that different mechanisms account for this expression in squamous and renal cell carcinomas.

The management of hypercalcemia of malignancy

Hypercalcemia (HCM) occurs in 10-15% of all malignancies, predominantly in patients with solid tumors. This metabolic complication leads to significant morbidity and impairment of quality of life. Recent insights into the pathophysiology of HCM include an understanding of the role of parathyroid-hormone-related peptide and several cytokines secreted by tumors. The osteoclast plays a central role as the final common pathway through which these hormones and cytokines act to cause bone lysis. These findings have led to the development of new treatment strategies. Foremost among these has been the introduction of agents such as the newer bisphosphonates and gallium nitrate, which are potent inhibitors of osteoclast-mediated bone resorption. The clinician can now choose from an array of therapeutic approaches based on a consideration of the mechanisms of action, individual clinical circumstances, efficacy, toxicities and costs of available agents. In addition to their use in the management of HCM, non-toxic drugs that effectively inhibit osteoclast function, such as the bisphosphonates, are playing an emerging role in the palliative treatment of the more common clinical problems of painful lytic bone metastases and osteoporosis.

Parathyroid hormone-related protein: primary osteolytic factor produced by breast tumor cells in vitro?

Tumor cells in bone metastases are thought to induce bone resorption primarily by releasing paracrine factors. Parathyroid hormone related protein (PTHrp) has been proposed to mediate osteolytic activity of many tumors. PTHrp is produced by 40% to 60% of breast tumors and is elevated in the serum of up to 50% of patients with breast cancer metastases to bone. Most biologic processes in humans are heterogeneous in nature, so the purpose of this study was to investigate the hypothesis that paracrine factors other than PTHrp could mediate bone resorption by breast tumor cells. Serum-free conditioned medium (CM) was collected from five human breast tumor cell lines and tested for bone resorption-stimulating activity (BRSA) in mouse calvaria organ cultures. CM from all tumor cells studied produced significant bone resorption, comparable to that produced by 10 nM PTH. Small amounts of immunoreactive PTHrp (1.4-12.5 pM) were produced by all breast tumor cell lines. When tested in vitro, equivalent amounts of human PTHrp [1-36] did not produce significant bone resorption. Indomethacin (1 microM) significantly blocked BRSA by CM from all cell lines but did not decrease BRSA by PTHrp. In contrast PTHrp antibody (130 micrograms/ml) completely blocked BRSA by 1 nM PTHrp but did not modify BRSA by CM of breast tumor cells. The results of this study support the hypothesis that breast cancer cells release paracrine factors in vitro that stimulate bone resorption by a mechanism that is partially dependent on prostaglandin synthesis and at least in part different from that of PTHrp.(ABSTRACT TRUNCATED AT 250 WORDS)

Parathyroid hormone-related protein

We review the current state of knowledge of the molecular properties and actions of parathyroid hormone-related protein (PTHrP) both in cancer patients and in normal physiology. PTHrP is a common product of squamous cancers and is the major mediator of the syndrome of humoral hypercalcemia of malignancy (HHM) by its actions through parathyroid hormone receptors in bone and kidney. Recently developed radioimmunoassays and tissue localization techniques indicate that PTHrP is produced by many more cancers than was originally indicated by clinical studies and that it contributes significantly to malignancy-related hypercalcemia associated with other etiologies, for example, cancers metastatic to bone and hematological malignancies. The gene encoding PTHrP is complex, with multiple exons coding for up to 12 alternate transcripts and three different length proteins, potentially in a tissue-specific manner, by the use of three promoters. Its expression is regulated by hormones and growth factors, and the untranslated exons display features in common with many cytokine genes. Although potential endocrine actions of PTHrP are evident in fetal development, further evidence suggesting that the normal physiological role of PTHrP is predominantly as a locally produced regulator/cytokine comes from localization studies and investigations of its actions in a variety of tissues. Such studies indicate that in addition to its parathyroid hormone-like actions, PTHrP has multiple activities, including those in fetal development, placental calcium transfer, lactation, smooth muscle relaxation, and on epithelial cell growth. Although PTHrP was discovered because of its production by cancers, evidence for its actions as a local regulator highlights the importance of understanding its roles not only in the etiology of HHM in cancer patients but also in normal tissues.

Comparative study of inhibitory effects by murine interferon gamma and a new bisphosphonate (alendronate) in hypercalcemic, nude mice bearing human tumor (LJC-1-JCK)

The inhibitory effect of murine interferon gamma (muIFN gamma) on humoral hypercalcemia in nude mice bearing lower-jaw cancer (LJC-1-JCK), in which parathyroid-hormone(PTH)-related protein is responsible for causing humoral hypercalcemia by activating bone resorption, was examined in comparison with that of a new bisphosphonate, 4-amino-1-hydroxybutylidene-1,1-bisphosphonate (alendronate). muIFN gamma was injected into tumor-bearing nude mice for 5 days before the establishment of hypercalcemia. The increase of plasma calcium concentration was delayed and this effect continued for more than 6 days even after the injection was stopped. Alendronate markedly suppressed hypercalcemia in tumor-bearing nude mice but this inhibitory effect continued for less than 6 days. Neither muIFN gamma nor alendronate affected the tumor volume or serum PTH-related protein concentration. Injection of muIFN gamma into mice for 3 days almost completely abolished the formation of multinucleated osteoclast-like cells from bone marrow cells in vitro, whereas injection of alendronate into mice had no effect. These findings suggested that muIFN gamma suppressed the formation of osteoclasts, resulting in the prolonged decrease of plasma calcium concentration in hypercalcemic tumor-bearing nude mice, whereas alendronate is cytotoxic to functionally mature osteoclasts and inhibited osteoclastic bone resorption, resulting in a marked decrease in the plasma calcium concentration in tumor-bearing hypercalcemic nude mice.

Malignancy-associated hypercalcaemia: resolution of controversies over vitamin D metabolism by a pathophysiological approach to the syndrome

OBJECTIVE

Parathyroid hormone-related protein (PTHrP) is recognized as a major pathogenetic factor of humoral hypercalcaemia of malignancy but its action on vitamin D metabolism is controversial. Our aim was to study the relation between serum 1,25-dihydroxyvitamin D and humoral activity in malignancy-associated hypercalcaemia.

DESIGN

Prospective, cross-sectional, single-centre study of patients with documented solid malignancies, hypercalcaemia and suppressed plasma PTH concentrations.

PATIENTS AND METHODS

Vitamin D metabolites, PTH, nephrogenous cyclic AMP (N-cAMP), PTHrP and biochemical parameters of calcium and bone metabolism were measured in 39 patients with solid malignancies and hypercalcaemia and bone scans were performed.

RESULTS

In 27 patients plasma PTHrP levels were elevated (69%) and in 9 patients (23%) serum 1,25-(OH)2D concentrations were not appropriately suppressed (> 92 pmol/l). Patients with plasma PTHrP levels below the upper limit of normal (< 1.6 pmol/l) had lower serum 1,25-(OH)2D concentrations than those with elevated levels (> 1.6 pmol/l) (47 +/- 6 vs 70 +/- 7 pmol/l, respectively; P < 0.04). Serum 1,25-(OH)2D concentrations were higher in patients with negative bone scans than in those with metastatic bone disease (80 +/- 9 vs 50 +/- 5 pmol/l; P < 0.01) and similar levels of plasma PTHrP. In the patients with negative bone scans there was a significant relation between plasma PTHrP and serum 1,25-(OH)2D (r = 0.51; P < 0.03) whereas there was no such correlation in those with a positive scan.

CONCLUSION

Contrary to current belief, serum 1,25-(OH)2D concentrations are not generally suppressed in humoral hypercalcaemia of malignancy and PTHrP is a determinant of these levels in the absence of demonstrable bone metastases. These findings provide further insights into the pathophysiology of malignancy-associated hypercalcaemia and may help in the clinical management of these patients.

Hypercalcaemia in B cell chronic lymphocytic leukaemia

Hypercalcaemia is common in some lymphoproliferative disorders such as myeloma or T-cell leukaemia-lymphoma, but is rarely described in B cell chronic lymphocytic leukaemia (BCLL). We report the case of a patient with BCLL, hypercalcaemia and osteolytic bone lesions. Parathyroid hormone-related protein (PTHrP) mRNA was identified by Northern blot analysis of liver, spleen and lymph node tumour samples. Serum levels of tumour necrosis factor alpha (TNF alpha) were increased.

Preclinical pharmacology of CGP 42'446, a new, potent, heterocyclic bisphosphonate compound

We have investigated the pharmacologic effects of a new bisphosphonate compound, CGP 42'446 [2-(imidazol-1-yl)-1-hydroxyethylidene-1,1-bisphosphonate], on bone metabolism. The compound exhibited potent inhibitory activity on the bone resorption induced by 1,25-dihydroxyvitamin D3 both in vivo in the thyroparathyroidectomized rat (ED50 0.072 microgram/kg SC) and in vitro in mouse calvarial cultures (IC50 0.002 microM). A comparison of the in vivo and in vitro inhibitory potencies of a total of nine bisphosphonates revealed an excellent correlation between the two assays (r = 0.97). CGP 42'446 also potently inhibited calvarial bone resorption induced by parathyroid hormone (1-34), parathyroid hormone-related protein (1-34), and recombinant human interleukin-1 beat. Short-term treatment of growing rats with CGP 42'H446 dose-dependently increased the radiographic density of the tibial proximal metaphysis (ED50 1.7 micrograms/kg SC) as well as increasing the calcium and hydroxyproline content of femoral trabeculae (ED50 values 0.17 and 1.1 micrograms/kg SC, respectively), but there was no detectable effect on cortical bone. On a molar basis in this range of in vivo screening assays, CGP 42'H446 was between 940-fold (thyroparathyroidectomized rat) and 87-fold (rat femoral trabecular calcium content) more potent than pamidronate. It is concluded that CGP 42'446 is a promising new, highly potent bisphosphonate for the suppression of the increased bone resorption associated with various diseases.

Primary disseminated form of Ewing sarcoma in association with hypercalcemia and acute renal failure

We present a case of an extremely rare form of Ewing sarcoma--primary disseminated, with fulminating course, severe hypercalcemia, extensive calcium deposition in parenchymatous organs, including kidneys, and acute renal failure as a clinical consequence. Correction of hypercalcemia was followed by prompt restoration of the glomerular filtration rate (GFR), suggesting that hypercalcemia had a direct effect on its regulation independent of the renal tubular damage. The effectiveness of the treatment with indomethacin indirectly supports the possibility of prostaglandin-mediated humoral hypercalcemia of malignancy.

Hypercalcemia and parathyroid hormone-related protein in hepatocellular carcinoma

A two-site immunoradiometric assay (IRMA) of parathyroid hormone-related protein (PTHrP) was employed to react with circulating concentrations of PTHrP in 14 patients with hepatocellular carcinoma (HCC) and hypercalcemia (> 10.6 mg/dl). Eleven of them had unresectable lesions and three received transcatheter arterial chemo-embolization (TACE) treatment. Patients had no evidence of bony metastases and only one had evidence of a parathyroid lesion (by bone scan and serum parathyroid hormone level, respectively). The urinary cAMP level was increased in all patients, but the serum 1,25-dihydroxyvitamin D and plasma cAMP levels varied. Twelve patients had elevated alpha-fetoprotein (AFP) (> 400 ng/ml) and two of them had mildly elevated AFP levels (11 and 147 ng/ml). Their PTHrP concentrations were elevated (7.1 to 33.2 pmol/l), compared with normal levels obtained in our laboratory (< 3.5 pmol/l). A significant decrease in plasma PTHrP (from 27.4 to 5.2 pmol/l), serum calcium concentrations (from 16.3 to 9.4 mg/dl) and AFP levels (from 64,787 to 3129 ng/ml) was observed on the day following TACE treatment. These results, by using an improved technique, extend the findings that hypercalcemia in patients with HCC is associated with increased renal reabsorption of calcium and increased bone resorption of PTHrP generated by HCC.