Primary hepatic carcinoid tumor presenting as Cushing's syndrome.

Hepatic carcinoid tumors are very uncommon; most are clinically non-functional and very few present with the symptoms of carcinoid syndrome. ACTH-producing carcinoid tumors most commonly originate in the lung or thymus and present insidiously with bronchospasm and/or chest mass. Occasionally, ectopic ACTH syndromes have been reported in association with pancreatic islet cell tumors, medullary thyroid cancer, pheochromocytoma, small-cell lung carcinoma, and rarely, ovarian and prostate tumors. We report here a patient with an ectopic ACTH-secreting primary hepatic carcinoid tumor who presented with cushingoid appearance, profound proximal muscle weakness, severe lower extremity edema, and markedly elevated urinary free cortisol. ACTH levels were in the low normal range. A solitary vascular hepatic lesion was found on magnetic resonance imaging, which was isodense with the surrounding liver on octreotide scan and photopenic on an 18-fluorodeoxyglucose (18FDG)-positron emission tomography (PET) scan. Following surgical resection of the hepatic tumor, histopathology confirmed an ACTH-secreting neuroendocrine tumor (NET), the patient had complete resolution of hypercortisolemic symptoms and remains in remission, now 4 yr after hepatic tumor resection. This case reports the first ACTH-secreting primary hepatic NET presenting as ectopic Cushing's syndrome. Interesting aspects of this case include the presence of a pituitary incidentaloma, the low normal ACTH, and photopenia on 18FDG-PET imaging.

Expression of pituitary tumour transforming gene (PTTG) and fibroblast growth factor-2 (FGF-2) in human pituitary adenomas: relationships to clinical tumour behaviour.

OBJECTIVE: Pituitary tumour transforming gene (PTTG) encodes a multifunctional protein that is implicated in initiating and perpetuating pituitary adenoma growth. PTTG appears to have key regulatory functions in determining control of many fundamental cellular events including mitosis, cell transformation, DNA repair and gene regulation. Several of these events are mediated through interactions with PTTG binding factor (PBF) and fibroblast growth factor-2 (FGF-2). Given this background, we have determined the expression of PTTG, PBF, FGF-2 and its receptor FGF-R-1 in a large cohort of pituitary adenomas and have sought associations between levels of gene expression and clinical markers of tumour behaviour. PATIENTS AND METHODS: We used real-time reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blot analyses to measure PTTG, PBF, FGF-2 and FGF-R-1 expression in ex vivo pituitary tumours (N = 121). Clinical data, including accurate radiological assessment of tumour characteristics, were used to determine any associations between gene expression and tumour behaviour. RESULTS: PTTG was increased significantly (fivefold, P = 0.005) in adenomas compared with normal pituitaries. We also demonstrated that PBF was similarly raised in adenomas (sixfold, P = 0.0001), and was significantly correlated with PTTG expression. FGF-2 and its receptor FGF-R-1 were also raised in adenomas compared with normal pituitary tissue. Moreover, significantly enhanced expression of FGF-R-1 was observed in invasive adenomas compared with other pituitary tumours. CONCLUSIONS: Our data support a fundamental role for PTTG-mediated upregulation of FGF-2 signalling in pituitary tumorigenesis and growth, and suggest that receptor-mediated mechanisms of growth factor action may be critically important. Further prospective studies are required to determine whether measurement of FGF-R-1 mRNA will be of clinical use as a prognostic marker in patients with pituitary adenomas.

Vascular endothelial growth factor, its receptor KDR/Flk-1, and pituitary tumor transforming gene in pituitary tumors.

Pituitary tumorigenesis is a poorly understood process involving dysregulation of the cell cycle, proliferation, and angiogenesis. The novel securin pituitary tumor transforming gene (PTTG) disrupts cell division and stimulates fibroblast growth factor (FGF)-2-mediated angiogenesis. We investigated expression of the angiogenic vascular endothelial growth factor (VEGF) and its receptor KDR/Flk-1 in 103 human pituitary tumors, and we assessed functional relationships between these genes in vitro. Nonfunctioning tumors (n = 81) demonstrated markedly raised VEGF mRNA (3.2-fold, P < 0.05) and protein concentrations, compared with normal pituitaries (n = 10). KDR was also highly induced in nonfunctioning tumors (14-fold, P < 0.001, n = 78) as well as in the whole cohort of pituitary tumors, compared with normal pituitary samples (14-fold, P < 0.0001, n = 100). In vitro, PTTG induced VEGF, but not KDR, expression in fetal neuronal NT2 cells (2.7-fold, P < 0.001, n = 8), MCF-7 breast carcinoma cells (1.9-fold, P = 0.03, n = 10), and choriocarcinoma JEG-3 cells (P = 0.0002, n = 8). A mutated PTTG construct that cannot be phosphorylated showed identical VEGF up-regulation (2.9-fold, P < 0.001, n = 8) in NT2 cells, compared with wild-type PTTG, but a further mutated construct with abrogation of the key protein:protein interaction domain of PTTG resulted in a significant reduction in VEGF stimulation, compared with wild-type (0.37-fold reduction, P < 0.001, n = 8). FGF-2 findings mirrored those of VEGF, although antibody depletion of secreted FGF-2 in the cell medium failed to influence VEGF up-regulation by PTTG. Overall, our findings implicate altered VEGF and KDR signaling in pituitary tumorigenesis, and we propose that PTTG stimulation of FGF-2 and VEGF expression in the presence of up-regulated growth factor receptors may account for angiogenic growth and progression of human pituitary tumors.

Transforming events in thyroid tumorigenesis and their association with follicular lesions.

Thyroid tumors comprise a broad spectrum of neoplastic phenotypes, and distinct molecular events have been implicated in their pathogenesis. Pituitary tumor transforming gene, originally isolated from GH(4) pituitary cells, is tumorigenic in vivo, regulates basic fibroblast growth factor secretion, and is homologous to a securin inhibitor of chromatid separation. Pituitary tumor transforming gene 1 is expressed at low levels in several normal human tissues and is abundantly expressed in neoplasms, including colorectal carcinoma, where pituitary tumor transforming gene expression correlated highly with tumor invasiveness. As pituitary tumor transforming gene is regulated by E and as thyroid cancer shows a strong female preponderance, we examined pituitary tumor transforming gene 1 expression and action in human thyroid tumors and in normal human and rat thyroid cells. Increased pituitary tumor transforming gene 1 expression was evident early in thyroid tumors and was most abundantly expressed in a subset of thyroid hyperplasia, follicular adenomas, and follicular carcinomas (1.8-fold; P < 0.0001). Pituitary tumor transforming gene 1 overexpression in rat FRTL5 thyroid cells and in primary human thyroid cell cultures causes in vitro transformation and produces a dedifferentiated neoplastic phenotype. As pituitary tumor transforming gene 1 was abundantly overexpressed in follicular adenoma and follicular carcinoma, we propose that pituitary tumor transforming gene overexpression may play a role in the early molecular events leading to divergent development of follicular and papillary carcinoma.

Human pituitary tumor-transforming gene induces angiogenesis.

Angiogenesis is a key determinant and rate-limiting step in tumor progression and metastatic spread. As pituitary tumor-transforming gene (PTTG) induces basic fibroblast growth factor (bFGF), we tested angiogenesis induced by conditioned medium (CM) derived from NIH-3T3 transfectants overexpressing wild-type human PTTG (WT-hPTTG-CM). We also examined the relationship between PTTG expression and tumor vascularity in a series of human tumors. CM from Wt-hPTTG transfectants induced proliferation, migration, and tube formation of human umbilical vein endothelial cells in vitro. The bFGF concentration in WT-hPTTG-CM was elevated (10.5 +/- 0.56) compared with CM from nontransfected NIH-3T3 cells (3.3 +/- 0.56 pg/mL), and addition of anti-bFGF antibody to CM abrogated these angiogenesis markers (P < 0.01). In vivo, concentrated WT-hPTTG-CM induced chick chorioallantoic membrane spoke-wheel-like appearances. Moreover, CM derived from hPTTG transfectants harboring a point mutation on the C-terminus proline-rich region of PTTG induced weaker angiogenic activity than WT-hPTTG-CM (P < 0.01). Thus, human PTTG induces an angiogenic phenotype in both in vitro and in vivo angiogenesis models, and high PTTG messenger ribonucleic acid is associated with an angiogenic phenotype in human tumors. These PTTG-directed angiogenic actions may be mediated through bFGF, which also contributes to tumor growth.

Pituitary tumor transforming gene causes aneuploidy and p53-dependent and p53-independent apoptosis.

The pituitary tumor transforming gene, PTTG, is abundantly expressed in several neoplasms. We recently showed that PTTG overexpression is associated with apoptosis and therefore have now studied the role of p53 in this process. In MCF-7 breast cancer cells that express wild type p53, PTTG overexpression caused apoptosis. p53 was translocated to the nuclei in cells expressing PTTG. Overexpression of p53, along with PTTG, augmented apoptosis, whereas expression of the human papillomavirus E6 protein inhibited PTTG-induced apoptosis. In MG-63 osteosarcoma cells that are deficient in p53, PTTG caused cell cycle arrest and subsequent apoptosis that was inhibited by caspase inhibitors. A proteasome inhibitor augmented PTTG expression in stable PTTG transfectants, suggesting that down-regulated PTTG expression is required for cell survival. Finally, MG-63 cells expressing PTTG showed signs of aneuploidy including the presence of micronuclei and multiple nuclei. These results indicate that PTTG overexpression causes p53-dependent and p53-independent apoptosis. In the absence of p53, PTTG causes aneuploidy. These results may provide a mechanism for PTTG-induced tumorigenesis whereby PTTG mediates aneuploidy and subsequent cell transformation.

New pituitary oncogenes.

Pituitary tumors are common monoclonal neoplasms which cause considerable morbidity and mortality. Several molecular events underlying pituitary tumorigenesis have been elucidated in recent years, but no tumor marker has clearly emerged which assists clinical and therapeutic decisions. Activating mutations and loss of inactivating mutations, together with hypothalamic hormones, circulating hormones, growth factors and cytokines cooperatively ensure the inexorable expansion of the initial mutated pituitary cell clone. This review describes new developments in our understanding of the molecular mechanisms involved in the pathogenesis of pituitary tumors. The availability of molecular probes will allow the early prediction of tumor behavior, identify targets for designing subcellular pituitary tumor therapy and provide novel approaches to pituitary tumor management.

Bilateral inferior petrosal sinus sampling in the differential diagnosis of adrenocorticotropin-dependent Cushing's syndrome: a comparison with other diagnostic tests.

To compare bilateral inferior petrosal sinus sampling (IPSS) with high dose dexamethasone (HDD) and CRH testing (using recently proposed stringent response criteria) in the differential diagnosis of ACTH-dependent Cushing's syndrome, we reviewed 53 consecutive cases. The main analysis was limited to 45 cases with confirmed diagnosis: 44 with pituitary dependency, proven by confirmatory histology and/or significant biochemical improvement after pituitary surgery, and 1 with ectopic ACTH syndrome. After HDD (2 mg every 6 h for 48 h), 21 of the 44 pituitary cases met the stringent more than 90% suppression criterion. Twenty-three of the 44 pituitary cases also underwent CRH testing; 16 of 23 met a stringent response criterion of a more than 50% serum cortisol rise. For HDD and CRH testing combined, 8 of 23 fulfilled both stringent criteria, 10 of 23 had discordant results, and 5 of 23 failed to fulfil either of the stringent criteria for pituitary dependency. IPSS was performed in all 44 of the proven pituitary cases; 36 had petrosal/peripheral ACTH ratios of 2.0 or more without CRH stimulation. Thus, in patients with proven pituitary disease, stringent response criteria to HDD and CRH testing were fulfilled by only 48% and 70%, respectively. IPSS, which gave direct evidence of pituitary ACTH secretion in 82% of the cases, is therefore considered necessary in a significant proportion of cases.

Expression of pituitary-tumour transforming gene in colorectal tumours.

BACKGROUND: Basic fibroblast growth factor promotes angiogenesis and mitogenesis in colon carcinomas. Pituitary-tumour transforming gene (PTTG1) causes in-vitro and in-vivo transformation, regulates secretion of basic fibroblast growth factor, and inhibits chromatid separation. Most normal tissues show little or no PTTG1 expression but cancer cells express the gene abundantly. We postulated that PTTG1 expression in colorectal tumours is related to tumour invasiveness. METHODS: PTTG1 gene and protein expression were assessed in 68 colorectal tumours and compared with invasive characteristics, such as lymph-node invasion, evidence of metastases, tumour vessel density, and expression of basic fibroblast growth factor. PTTG1 expression is given in terms of the fold-increase over that in normal-adjacent colorectal tissue. FINDINGS: PTTG1 was overexpressed in all of 48 colon carcinomas (median fold-increase 2.2 [IQR 1.8-3.3]) and in 19 of 20 colonic polyps (2.2 [1.6-3.1]) compared with normal colonic tissue. Invasion of surrounding lymph nodes was associated with higher PTTG1 expression than in carcinomas limited to the bowel wall (3.4 [2.1-5.9] vs 1.9 [1.7-2.4], p=0.007), and higher PTTG1 expression was seen in more vascular than in less vascular tumours (2.6 [1.9-5.1] vs 1.9 [1.8-2.5], p=0.04). INTERPRETATION: Increased tumour PTTG1 expression may be a marker of invasive colorectal carcinoma and could represent a new therapeutic target.

Immunohistochemical evaluation of the post-translational processing of chromogranin A in human pituitary adenomas.

Chromogranin A (CgA), pancreastatin (PST), intervening-peptide (IP) and WE-14 antisera were employed to investigate the proteolysis of CgA in 50 pituitary adenomas. All non-functioning (NF) pituitary tumours (n = 28) exhibited CgA immunoreactivity. PST, IP and WE-14 immunostaining was observed in 85%, 89% and 67%, respectively. CgA, PST and IP immunostaining were comparable in the majority of NF tumours, while less intense WE-14 immunoreactivity was detected in a subpopulation of NF tumour cells. Approximately half of the functioning pituitary tumours expressed CgA immunoreactivity. Six of nine ACTH-secreting tumours displayed CgA and IP immunostaining; four of these tumours displayed PST immunoreactivity. WE-14 immunoreactivity was detected in one corticotroph tumour. Three of six growth hormone (GH) secreting tumours displayed CgA immunostaining, two exhibited PST and IP, and one exhibited WE-14 immunoreactivity. Clusters of WE-14 immunopositive cells were detected in one GH tumour. One of seven prolactinomas exhibited weak CgA immunostaining, while weak IP and WE-14 immunostaining was detected in an additional tumour. No PST immunostaining was detected in prolactinomas. Therefore CgA is a valuable marker of NF pituitary tumours, however it is a more sporadic marker of functioning adenomas. In general, the cellular pattern and intensities of CgA, PST and IP immunoreactivity were comparable in the majority of pituitary adenomas. In contrast, WE-14 immunostaining was observed in a subpopulation of tumour cells. The pathophysiological significance of the proteolysis of CgA to generate bioactive peptides in both NF and functioning pituitary adenomas remains to be established.

Early involvement of estrogen-induced pituitary tumor transforming gene and fibroblast growth factor expression in prolactinoma pathogenesis.

Pituitary tumors are commonly encountered, and result from clonal expansion of a single mutated cell. Hypothalamic hormones, local growth factors and circulating sex steroid hormones promote pituitary tumor growth and expansion into large invasive tumors. Estrogen acting directly through its receptor and by stimulation of fibroblast growth factor regulates prolactin synthesis and secretion. Fibroblast growth factor-2 (bFGF) modulates angiogenesis, tumor formation and progression in many tissues, including the anterior pituitary. A pituitary tumor-derived transforming gene (PTTG) has been isolated, which is tumorigenic in vivo, regulates bFGF secretion, and inhibits chromatid separation. The human PTTG family consists of at least three homologous genes, of which PTTG1 is located on chromosome 5q33 and is expressed at low levels in most normal human tissues but is highly expressed in malignant human cell lines and in pituitary tumors. We report here that pituitary pttg is regulated in vivo and in vitro by estrogen. Maximal induction of rat pituitary pttg mRNA in vivo occurred early in pituitary transformation (normal cell to hypertrophic/hyperplastic cell), coincident with bFGF and vascular endothelial growth factor induction and pituitary angiogenesis. We also demonstrate that pttg expression is induced by bFGF, and show concordant pttg and bFGF expression in experimental and human pituitary adenomas. As bFGF and estrogen both induce pttg, and pttg expression coincides with the early lactotrophic hyperplastic response, angiogenesis and prolactinoma development, we propose a previously unknown paracrine growth factor-mediated mechanism for pituitary tumor pathogenesis and potentially other estrogen-regulated tumors.

Increased pressor response to noradrenaline in pituitary dependent Cushing's syndrome.

OBJECTIVES: The mechanism of hypertension in Cushing's syndrome remains undetermined. Some studies have demonstrated an increased sensitivity to pressor agents but it is not clear if patients with Cushing's syndrome of different aetiologies demonstrate this finding. We have examined pressor sensitivity in a group of patients with Cushing's disease (pituitary dependent hypercortisolism) by measuring blood pressure during incrementally increasing infusions of noradrenaline. METHODS: Eight subjects (7 female, 1 male), aged 42.2 +/- 4.5 years (mean +/- SEM) with Cushing's disease were studied. Eight age- and sex-matched control subjects were also studied. Four of the eight controls and five patients with Cushing's disease had elevated blood pressure. All medication for this had been stopped at least seven days prior to the study. After subjects ate a light breakfast, ECG leads and a sphygmomanometer were attached, an intravenous cannula was inserted and all subjects then rested quietly for 60 minutes. Noradrenaline was then infused intravenously for 10-minute periods at concentrations of 0.01, 0.03, 0.07, 0.11 and 0.18 microg/kg/minute. RESULTS: On the day of the study the baseline blood pressures and pulse rates in the patients with Cushing's disease (blood pressure; 138/87 +/- 6/3 mmHg, pulse 76.5 +/- 4.8 beats/minute) and controls (blood pressure; 126/86 +/- 6/6 mmHg, pulse 71.2 +/- 3.7 beats/minute) were not significantly different. The mean change in diastolic blood pressure from baseline at the time of the peak increase or when the test was stopped was 21. 5 +/- 4.7 mmHg in Cushing's disease compared to 7.0 +/- 2.5 mmHg in controls (P = 0.03). The mean change in mean arterial pressure from baseline at the time of the peak increase or when the test was stopped was 22.0 +/- 4.0 mmHg in Cushing's disease compared to 13.0 +/- 2.4 mmHg in controls (P = 0.03). No significant difference in mean change of systolic pressure (26.0 +/- 4.6 vs. 25 +/- 4.0 mmHg) or pulse rates (- 11.1 +/- 1.8 vs. - 4.7 +/- 2.6) was seen in the group with Cushing's disease as compared to the control group. CONCLUSIONS: We conclude that patients with pituitary-dependent Cushing's syndrome have enhanced pressor diastolic and mean arterial responses to noradrenaline and this may be an important underlying mechanism for the hypertension seen in this particular group of Cushing's syndrome patients.

Prevention of recurrent pancreatitis in familial lipoprotein lipase deficiency with high-dose antioxidant therapy.

We describe a dramatic response to antioxidant therapy in three patients with familial lipoprotein lipase deficiency complicated by frequent severe episodes of pancreatitis who had failed to respond to other dietary and pharmacological measures. Antioxidant therapy may be an important advance in the management of this type of patient.

Pituitary tumor transforming gene (PTTG) expression in pituitary adenomas.

We recently cloned a novel pituitary tumor transforming gene (PTTG). Here we report PTTG expression in human pituitary adenomas and in normal pituitary tissue. In situ hybridization revealed PTTG expression in nonfunctioning and in GH-secreting adenomas but not in normal pituitary tissue. Using a more sensitive detection method, RT-PCR, low level PTTG expression was detected in normal pituitary. However, when expression levels in normal pituitary tissue were compared with those in 54 pituitary tumors using comparative reverse transcription polymerase chain reaction (RT-PCR), we found that most tumor samples expressed higher levels of PTTG. More than 50% PTTG increases were observed in 23 of 30 nonfunctioning pituitary tumors, all 13 GH-producing tumors, 9 of 10 prolactinomas, and 1 ACTH-secreting tumor, with more than 10-fold increases evident in some tumors. Furthermore, higher PTTG expression (P = 0.03) was observed in hormone-secreting tumors that had invaded the sphenoid bone (stages III and IV; 95% CI 3.118-9.715) compared with hormone-secreting tumors that were confined to the pituitary fossa (stages I and II; 95% CI 1.681-3.051). Therefore, PTTG abundance is a molecular marker for invasiveness in hormone-secreting pituitary tumors. The ubiquitous and prevalent expression of pituitary adenoma PTTG suggests that PTTG plays a role in pituitary tumorigenesis and invasiveness.

Pituitary tumour transforming gene: a novel factor in pituitary tumour formation.

Although pituitary tumours are common monoclonal neoplasms, they rarely metastasize outside the pituitary fossa, even though they cause considerable morbidity and mortality. Many molecular events underlying pituitary tumourigenesis have been elucidated in recent years, but no clear tumour marker has emerged that assists clinical decision-making with regard to appropriate therapy. Activating mutations and a loss of inactivating mutations, together with hypothalamic hormones, circulating hormones, growth factors and cytokines, co-operatively ensure the inexorable expansion of the initial mutated pituitary cell clone. We have recently described a novel oestrogen-regulated activating oncogene, pituitary tumour transforming gene (PTTG), which is potently transforming in vitro and in vivo, regulates basic fibroblast growth factor secretion and inhibits chromatid separation. In experimental animal pituitary tumour models, increased PTTG expression occurs early in cell transformation (from normal to hyperplastic cell), PTTG overexpression being observed in 99% of pituitary tumours. PTTG presents an attractive target for designing subcellular pituitary tumour therapy, and an increased understanding of its role and that of other genetic events in pituitary tumorigenesis may provide novel approaches to pituitary tumour management.

Insulin action and hepatic glucose cycling in Cushing's syndrome.

OBJECTIVE: Although it is well established that hypercortisolism causes insulin resistance, the mechanisms responsible for impaired insulin action in Cushing's syndrome are unclear. This study investigated the contribution of the glucose/glucose-6-phosphate substrate cycle (G/G6P). PATIENTS: Eight patients with Cushing's syndrome and seven control subjects were studied. All had normal fasting plasma glucose. DESIGN: Insulin action was assessed using the euglycaemic glucose clamp at insulin infusion rates of 0.4 and 2.0 mU/kg/min combined with a simultaneous infusion of [2(3)H]- and [6(3)-H]-glucose. Glucose/ glucose-6-phosphate cycle activity was calculated as the difference in glucose turnover rates determined separately for [2(3)H]- and [6(3)H]-glucose by selective enzymatic detritiation. MEASUREMENTS AND RESULTS: Exogenous glucose infusion rates required to maintain euglycaemia were significantly lower in Cushing's patients compared to controls, during the 0.4 mU/kg/min (7.8 +/- 1.2 vs 15.7 +/- 0.5 mumol/kg/min, P < 0.001) and the 2.0 mU/ kg/min insulin infusions (26.2 +/- 2.8 vs 51.5 +/- 3.5 mumol/ kg/min, P < 0.001). Endogenous glucose production was similar in both groups in the postabsorptive state (10.2 +/- 0.3 vs 10.8 +/- 0.4 mumol/kg/min, P = 0.50) and suppressed to a similar degree during hyperinsulinaemia. G/G6P cycle activity was markedly increased in the Cushing's group in the postabsorptive state (5.4 +/- 1.1 vs 2.0 +/- 0.5 mumol/kg/min, P = 0.028) and during the 0.4 mU/kg/min (3.2 +/- 0.6 vs 1.2 +/- 0.4 mumol/kg/min, P = 0.014) and 2.0 mU/kg/min insulin infusions (3.3 +/- 0.8 vs 1.1 +/- 0.5 mumol/kg/min, P = 0.049). CONCLUSIONS: Patients with Cushing's syndrome show marked peripheral insulin resistance and enhanced hepatic G/G6P cycle activity. In the fasting state increased glucose/glucose-6-phosphate cycle activity may be a protective mechanism limiting hyperglycaemia. During hyperinsulinaemia G/G6P cycle activity was increased but insulin resistance was predominantly due to reduced peripheral glucose uptake.

Expression of bcl-2 oncoprotein in pituitary tumours: comparison with c-myc.

AIMS/BACKGROUND: Whereas the control of hormone secretion from pituitary adenomas has been studied in considerable detail, the molecular events underlying the development of these tumours are still poorly understood. Abnormalities of some oncogenes and tumour suppressor genes have been previously reported to occur at very low frequencies. The aim of the present study was to assess the possible expression of the bcl-2 oncoprotein and to compare it with that of c-myc in pituitary adenomas. METHODS: Monoclonal antibodies were used, along with microwave antigen retrieval and the avidin-biotin immunohistochemical method, to investigate expression of the oncoproteins bcl-2 and c-myc in 30 primary pituitary tumours from five broad diagnostic groups and in five normal pituitaries. RESULTS: Bcl-2 and c-myc immunoreactivities were detected in nine (30%) and eight (27%) tumour samples, respectively. Of the nine bcl-2 and eight c-myc positive tumours, seven were positive for both oncoproteins and included one of the four corticotrophinomas studied, four of seven prolactinomas, one of two somatotrophinomas, and one of four oncocytomas. All 13 null cell adenomas studied were negative for both bcl-2 and c-myc immunoreactivities. CONCLUSIONS: These results indicate that the bcl-2 and c-myc oncoproteins are expressed abnormally in over one quarter of pituitary tumours. Most these tumours co-expressed both oncoproteins. The genetic complementation of simultaneously deregulated bcl-2 and c-myc is implicated, through the regulation of apoptosis, in the pathogenesis of pituitary tumours.

Flow cytometric analysis does not reliably differentiate benign from malignant phaeochromocytoma.

BACKGROUND AND OBJECTIVE: The differentiation of benign from malignant phaeochromocytoma is difficult. We have examined whether the use of flow cytometric determination of nuclear DNA content would be useful as a predictor of malignant behaviour in patients with phaeochromocytoma as some previous studies had suggested that a diploid cytometric DNA pattern indicated benign disease. DESIGN AND PATIENTS: DNA flow cytometry was performed on phaeochromocytoma tissue from 36 patients (19 female, 17 male; mean age at presentation 39.5 years). The results were correlated with clinical outcome after prolonged follow-up. MEASUREMENTS: DNA histograms were constructed following nuclear suspension analysis. RESULTS: Of 26 patients followed up for more than 5 years after initial removal of primary phaeochromocytoma, three have died from malignant recurrence. In these patients a diploid DNA cytometric pattern was observed in two and an aneuploid pattern in one. Twenty-one patients are still alive. DNA cytometry showed a diploid pattern in the one patient who developed recurrent phaeochromocytoma 4 years after removal of a primary tumour. CONCLUSION: In this study, three of nine patients with an apparently benign diploid cytometric pattern subsequently developed recurrent disease. Routine use of DNA flow cytometry did not reliably differentiate benign from malignant phaeochromocytoma. Prolonged clinical and biochemical follow-up is still necessary for all patients with this condition.