Peritoneal carcinomatosis from small intestinal neuroendocrine tumors: Clinical course and genetic profiling

BACKGROUND

One-fifth of all patients with small-intestinal neuroendocrine tumors (SI-NETs) present with or develop peritoneal carcinomatosis (PC). Our aim was to determine the prognosis and genetic profiles of tumors in patients with PC compared with tumors in patients without PC.

METHODS

We included SI-NET patients (cases with PC, n = 73, and controls without PC, n = 468) who underwent operation between 1985 and 2012. The Lyon prognostic index was used to correlate the amount of PC to survival. DNA samples from patients with (n = 8) and without (n = 7) PC were analyzed with a single-nucleotide polymorphism array (HumanOmni2.5 BeadChip, Illumina) to investigate genetic disparities between groups.

RESULTS

Patients with PC had poorer survival (median 5.1 years) than controls (11.1 years). An advanced postoperative Lyon prognostic index was a negative prognostic marker for survival by multivariable analysis (P = .042). Patients with and without PC clustered differently based on loss of heterozygosity and copy number variation data from single-nucleotide polymorphism array of the primary tumors (P = .042).

CONCLUSION

SI-NET patients with PC have poor survival, which diminishes with increasing PC load after surgery. Clustering based on copy number variation and loss of heterozygosity data suggests different genotypes in primary tumors comparing patients with and without PC.

Integrative epigenomic and genomic analysis of malignant pheochromocytoma

Epigenomic and genomic changes affect gene expression and contribute to tumor development. The histone modifications trimethylated histone H3 lysine 4 (H3K4me3) and lysine 27 (H3K27me3) are epigenetic regulators associated to active and silenced genes, respectively and alterations of these modifications have been observed in cancer. Furthermore, genomic aberrations such as DNA copy number changes are common events in tumors. Pheochromocytoma is a rare endocrine tumor of the adrenal gland that mostly occurs sporadic with unknown epigenetic/genetic cause. The majority of cases are benign. Here we aimed to combine the genome-wide profiling of H3K4me3 and H3K27me3, obtained by the ChIP-chip methodology, and DNA copy number data with global gene expression examination in a malignant pheochromocytoma sample. The integrated analysis of the tumor expression levels, in relation to normal adrenal medulla, indicated that either histone modifications or chromosomal alterations, or both, have great impact on the expression of a substantial fraction of the genes in the investigated sample. Candidate tumor suppressor genes identified with decreased expression, a H3K27me3 mark and/or in regions of deletion were for instance TGIF1, DSC3, TNFRSF10B, RASSF2, HOXA9, PTPRE and CDH11. More genes were found with increased expression, a H3K4me3 mark, and/or in regions of gain. Potential oncogenes detected among those were GNAS, INSM1, DOK5, ETV1, RET, NTRK1, IGF2, and the H3K27 trimethylase gene EZH2. Our approach to associate histone methylations and DNA copy number changes to gene expression revealed apparent impact on global gene transcription, and enabled the identification of candidate tumor genes for further exploration.

Increased 25-hydroxyvitamin D3 1alpha-hydroxylase and reduced 25-hydroxyvitamin D3 24-hydroxylase expression in parathyroid tumors--new prospects for treatment of hyperparathyroidism with vitamin d

Vitamin D analogues are in clinical use for prevention and treatment of secondary hyperparathyroidism (HPT) in chronic renal failure. Despite recent advances there is a need for vitamin D derivatives with maintained parathyroid hormone suppressive activity and less hypercalcemic and hyperphosphatemic toxicity. Here we show coincident increased expression of the vitamin D activating enzyme 25-hydroxyvitamin D(3) 1alpha-hydroxylase (1alpha-hydroxylase) and reduced expressions of the 1,25(OH)(2)D(3) catabolizing enzyme 25-hydroxyvitamin D(3) 1alpha-hydroxylase (1alpha-hydroxylase) in the majority of investigated parathyroid adenomas and secondary hyperplastic glands. In addition, this relationship was found for the mitochondrial CYP27A enzyme (25-hydroxylase), a potential physiological vitamin D(3) 25-hydroxylase. These findings should be considered in future development of vitamin D analogues for treatment of HPT.

Exclusive underexpression of vitamin D receptor exon 1f transcripts in tumors of primary hyperparathyroidism

OBJECTIVE

Primary hyperparathyroidism (pHPT) is characterized by excessive production of parathyroid hormone (PTH) due to parathyroid adenomas while uremic secondary HPT (sHPT) is caused by parathyroid hyperplasia in response to renal failure. Active vitamin D, 1,25-dihydroxyvitamin D(3) (1,25-(OH)(2)D(3)), with the vitamin D receptor (VDR) is involved in regulation of the calcium homeostasis together with PTH. In a feedback loop, 1,25-(OH)(2)D(3) has a direct action on the parathyroid gland to regulate PTH transcription, PTH secretion and cell proliferation. We have previously demonstrated reduced VDR mRNA expression in parathyroid adenomas and hyperplasia of sHPT using a probe detecting all 14 variant VDR transcripts expressed in parathyroid cells. Here we have assessed which of the 5'-terminal exon 1a, 1d and 1f variant VDR transcripts are reduced in pathological parathyroid glands.

METHODS

The relative VDR/glyceraldehyde-3-phosphate dehydrogenase mRNA levels for each VDR exon were determined by real-time quantitative RT-PCR in five normal parathyroid glands, seventeen parathyroid adenomas and ten hyperplastic glands of sHPT.

RESULTS

The results demonstrated exclusive underexpression of VDR exon 1f transcripts in parathyroid adenoma, while all measured VDR transcripts were reduced in secondary hyperplasia.

CONCLUSIONS

We suggest that exclusive underexpression of VDR exon 1f transcripts in adenomas of pHPT, which derive from a distal promoter active in tIssues involved in calcium regulation by 1,25-(OH)(2)D(3), may either reflect a defective cell type-specific transcription factor or other physiologically important pathway(s) for tIssue-specific VDR gene expression.

Midgut Carcinoids and Solid Carcinomas of the Intestine: Differences in Endocrine Markers and p53 Mutations

Fifteen midgut carcinoid tumors and 5 solid carcinomas of the intestine with carcinoid-like morphological features were evaluated histochemically and immunohistochemically with respect to various endocrine markers and expression of mutant p53 protein. Direct sequencing of the p53 gene after PCR amplification was carried out on microdissected cells from all tumors. All investigated carcinoid tumors showed chromogranin and argentaffin reaction, but lacked nuclear immunostaining with p53 antibodies. In 14 immunohistochemically negative midgut carcinoid tumors, no mutations were identified. One carcinoid tumor devoid of p53 staining was, however, found to contain mutation in exon 6 of the p53 gene. In contrast, the solid carcinomas were essentially chromogranin negative but all displayed clearly positive p53 staining in a variable number of cell nuclei. Sequence analysis of exons 5-8 of the p53 gene in the 5 carcinomas showed mutations in exons 6 and 7 in 2 tumors and in exon 8 in 2 other tumors, while no mutation was detected in the fifth tumor. The carcinoid tumors and the solid carcinomas of the small intestine are thought to derive histogenetically from endocrine cells and enterocytes, respectively. The present results substantiate that divergent mechanisms operate in the development of the two tumor types.

Monoclonal Antibodies Recognizing Normal and Neoplastic Human Adrenal Cortex

Four monoclonal antibodies (MAb) were generated by immunization of mice with dispersed cells from normal human adrenal gland (Na) and adrenocortical adenoma causing cortisol excess (Ac). Immunohistochemically reacted cryosections revealed differential labeling of the normal cortical parenchyma, and immunofluorescence on dispersed cells displayed that Ac5 alone labeled the cell surface. Immunoprecipitation demonstrated that the antibodies recognized apparently different structures of 51-88 kDa. Immunohistochemical examination of several normal human tissues substantiated restricted reactivity, especially for the Na2 and Na7 antibodies, and that the adrenal medulla was not stained by any of the antibodies. The antibodies recognized the vast majority of the parenchymal cells of cortical adenomas (n = 21). Each antibody also reacted with all adrenocortical carcinomas (n = 17), and the staining generally was most intense and extensive with Na7. Analysis of other pathological human tissues revealed highly restricted reactivity for the Na2 antibody. Na2 and Na5 failed to stain 17 renal cell carcinomas. None of the antibodies recognized pheochromocytomas. These antibodies may lead to improved histological recognition and characterization of human adrenal lesions.

Variable p-glycoprotein immunoreactivity unrelated to cytotoxic drug-resistance in-vitro of human adrenocortical carcinoma

Human adrenocortical tissue was immunohistochemically investigated with monoclonal antibodies C219 and JSB-1 for expression of P-glycoprotein (Pgp) associated with resistance to multiple cytotoxic drugs. All normal (n=7) and adenomatous (n=3) glands strongly expressed the protein, while the cancers (n=15) demonstrated variable Pgp reactivity. Cytotoxic drug sensitivity testing in vitro on freshly dispersed cells from one normal adrenal gland and from 6 carcinomas with no to extensive Pgp reactivity demonstrated universally poor sensitivity to 9 standard drugs including those with Pgp mediated resistance. The findings indicate that immunohistochemical staining for Pgp cannot be used to predict cytotoxic drug resistance and that other mechanisms mediate cytotoxic drug resistance in adrenocortical carcinoma.

Effects of physical exercise on serum calcium and parathyroid hormone

The effects of physical exercise on plasma ionized calcium, total serum calcium and parathyroid hormone (PTH) concentrations were evaluated in healthy subjects submitted to work on an ergometer bicycle. When the workload was increased stepwise there was a significant increase (P less than 0.001) in the calcium concentrations (ionized calcium from 1.13 +/- 0.03 (SD) to 1.24 +/- 0.03 mmol 1(-1) and total calcium from 2.35 +/- 0.07 to 2.48 +/- 0.07 mmol 1(-1] when the workload exceeded approximately 65% of the estimated maximum--i.e. a load that caused accumulation in blood of lactic acid. The rise in plasma ionized calcium was, therefore, presumably largely attributed to the acidosis but reduction of plasma volume and influx from extracellular sources might also have contributed. Beta blockade (with oral intake of propranolol) reduced physical capacity, shortened the duration of work and caused less acidosis. These factors were probably responsible for a smaller rise in ionized calcium during beta blockade (7 +/- 4%) than in control studies (21 +/- 5%) without medication in subjects examined during short-term maximal exercise. Long-term (1 h) steady-state work which caused fatigue without producing lactic acidosis did not affect the calcium concentrations. Despite the effects of work on calcium levels there was no discernible suppression of the PTH concentrations. This might have been due to a concomitant stimulation of PTH secretion by work.

Screening for multiple endocrine neoplasia syndrome (type 1) in patients with primary hyperparathyroidism

In 63 consecutive patients with primary hyperparathyroidism (HPT) a prospective screening study was undertaken for coexistent multiple endocrine neoplasma-(MEN)-syndrome type 1. The screening consisted of a clinical examination, a radiological examination of the sella turcica with skeletal tomography (and in equivocal cases computed tomography), visual field examination by perimetry and a hormonal evaluation including measurements of the serum levels of prolactin, gastrin, pancreatic polypeptide (PP) and subunits of human chorionic gonadotrophin (HCG-alpha and -beta). Clinical examination did not reveal any signs of endocrine disease suggestive of a MEN-1 syndrome. In only one case there was a radiological abnormality of the sella turcica; this patient had an empty sella syndrome and a raised serum prolactin value. All other prolactin values were within the normal range. In 41% of the patients raised serum gastrin levels were found; these tended to normalize after parathyroidectomy. As a group, patients with raised gastrin values were older than the others and generally they had hypo- or achlorhydria. The serum PP levels were raised in 28% of the patients but there was no clinical evidence of a pancreatic tumour in any of these cases, and the serum HCG-alpha and -beta levels were within the normal range in all patients but two. We conclude that the incidence of MEN-1 syndrome in unselected patients with primary HPT must be low, and that investigations for this syndrome are justified only in HPT patients with specific symptoms or with a positive family history.