Shereen Ezzat

Immunohistochemical Diagnosis of Papillary Thyroid Carcinoma

In thyroid, the diagnosis of papillary carcinoma (PC) is based on nuclear features; however, identification of these features is inconsistent and controversial. Proposed markers of PC include HBME-1, specific cytokeratins (CK) such as CK19, and ret, the latter reflecting a ret/PTC rearrangement. We applied immunohistochemical stains to determine the diagnostic accuracy of these three markers. Formalin-fixed, paraffin-embedded tissue from 232 surgically resected thyroid nodules included 40 hyperplastic nodules (NH), 35 follicular adenomas (FA), 138 papillary carcinomas (PC; 54 classical papillary tumors and 84 follicular variant papillary carcinomas [FVPC]), 4 follicular carcinomas (FC), 6 insular carcinomas (IC), 7 Hürthle cell carcinomas (HCC), and 2 anaplastic carcinomas (AC). HBME-1 and ret were negative in all NH and FA; some of these exhibited focal CK19 reactivity in areas of degeneration. Half of the FC and AC exhibited HBME-1 staining but no positivity for CK19 or ret. In PC, 20% of cases stained for all three markers. Classical PC had the highest positivity with staining for HBME-1 in 70%, CK19 in 80%, and ret in 78%. FVPC were positive for HBME-1 in 45%, for CK19 in 57%, and for ret in 63%; only 7 FVPC were negative for all three markers. The six IC exhibited 67% staining for HBME-1 and 50% positivity for CK19 and ret. The seven HCC had 29% positivity for HBME-1 and CK19, and 57% positivity for ret. This panel of three immunohistochemical markers provides a useful means of diagnosing PC. Focal CK19 staining may be found in benign lesions, but diffuse positivity is characteristic of PC. HBME-1 positivity indicates malignancy but not papillary differentiation. Only rarely are all three markers negative in PC; this panel therefore provides an objective and reproducible tool for the analysis of difficult thyroid nodules.

Acromegaly. Clinical and biochemical features in 500 patients.

This prospective study defines the clinical and biochemical features of acromegaly in a large cohort of patients. There was no difference in sex distribution, and for men and women the mean ages at diagnosis (40 +/- 12 and 40 +/- 14 yr, respectively) were similar. Nearly three-quarters of patients were overweight and some 12% severely overweight; the frequency and severity of obesity also was not different between the sexes. Half of patients were hypertensive or were taking anti-hypertensive drugs. Neither GH nor insulin levels were significantly different between normotensive and hypertensive patients. Acral growth and facial coarsening, soft tissue swelling, and excessive perspiration were present in the majority (98%) of patients. Mean serum GH, Sm-C, and PRL levels did not differ between the sexes. Sm-C levels correlated with mean GH concentration (r = 0.31, p < 0.001), both variables inversely related to age. With each decade of life, mean GH and Sm-C levels declined by 7.6 +/- 0.2 ng/mL and 0.5 +/- 0.2 U/mL, respectively. Impaired glucose tolerance was diagnosed in 36% and frank diabetes mellitus in 30% of patients. Hyperprolactinemia was noted in 18% of patients. Galactorrhea was noted in 43 (9%) patients, most of whom were female; the mean GH levels of patients with galactorrhea (60.1 +/- 13 ng/mL) were higher than those of patients without (35.4 +/- 2.6 ng/mL, p = 0.02). Acromegaly appears to afflict men and women equally with a preponderance of presentation in the fourth decade of life.(ABSTRACT TRUNCATED AT 250 WORDS)

Acromegaly: Re-thinking the cancer risk

Acromegaly is characterized by sustained elevation of circulating growth hormone (GH) and insulin-like growth factor I (IGF-I), and is clearly associated with increased morbidity and overall mortality mainly due to cardiovascular, metabolic, and respiratory diseases. Although cancer-related mortality varies widely amongst retroperspective studies, it appears to be consistently elevated mainly in patients with uncontrolled disease. We review individual tumor types including neoplasms of the colon, breast, prostate, and thyroid where in vitro, animal studies, and studies in non-acromegalic cancer patients have established a role for the GH/IGF-I axis in tumor progression and possibly initiation. We highlight deficiencies in data in acromegalic patients where the evidence is less convincing. Instead, we explore the hypothesis that acromegaly, independent of hormone secretion, is a disease that heralds genetic and/or epigenetic alterations predisposing to cancer risk elsewhere.

A randomized, controlled, multicentre trial comparing pegvisomant alone with combination therapy of pegvisomant and long-acting octreotide in patients with acromegaly

Objectiveu2002 For patients with acromegaly who are suboptimally controlled on long‐acting octreotide (LAR), treatment options are to switch to pegvisomant monotherapy (PM) or add pegvisomant to LAR (P‐LAR). Our objective was to evaluate if the safety and efficacy of these regimens differ.

Oncogene profile of papillary thyroid carcinoma

BACKGROUNDnOur purpose was to study the expression of multiple oncogenes in papillary thyroid cancer for possible interactions and prognostic significance.nnnMETHODSnTwenty papillary thyroid carcinomas were studied for expression/mutation of 3 oncogenes: ras, ret/PTC, and erbB-2/neu. H, N, and K ras codons were examined by polymerase chain reaction (PCR), single-stranded conformation polymorphism, and sequencing. The thyroid oncogene ret/PTC was identified by reverse transcription (RT)-PCR. Gene amplification of erbB-2/neu was analyzed by differential PCR. The transmembrane domain of erbB-2/neu was sequenced for activating mutations. Quantitation of erbB-2/neu mRNA was evaluated by competitive RT-PCR, and protein expression was determined by immunohistochemistry.nnnRESULTSnAmong 20 tumors, 3 had insular/anaplastic dedifferentiation, 13 were intrathyroidal, and 7 were metastatic to cervical lymph nodes (6) or lung (1). An H-ras 13 mutation was found in 1 metastatic tumor and an N-ras 61 mutation in 1 intrathyroidal tumor. ret/PTC was identified in 3 intrathyroidal and 5 metastatic tumors. No erbB-2/neu DNA amplification or mutations were identified, although 4 tumors had elevated erbB-2/neu mRNA levels. Three of 20 patients had abnormalities detected in multiple oncogenes; 2 had elevated erbB-2/neu mRNA and ret/PTC rearrangements, and 1 of these had pulmonary metastasis. An intrathyroidal papillary cancer had an N61 ras mutation and a ret/PTC gene rearrangement.nnnCONCLUSIONSnret/PTC rearrangements are present in 40% of papillary thyroid carcinomas and may play a role in metastatic behavior. In contrast, ras mutations are rare (10%). erbB-2/neu gene amplification and activating mutations are not detected, although elevated mRNA levels were found in 20% of papillary carcinomas. The lack of correlation among the 3 oncogenes in 17 of 20 (85%) papillary thyroid carcinomas suggests that they were not cumulative factors in the pathogenesis of these tumors.

Evidence for Growth Hormone (GH) Autoregulation in Pituitary Somatotrophs in GH Antagonist-Transgenic Mice and GH Receptor-Deficient Mice

Growth hormone (GH) modulates the hypothalamic release of somatostatin and GH-releasing hormone; however, there has been no evidence of GH autoregulation on the pituitary somatotroph. To determine the effects of GH on its own regulation, we examined the pituitaries of giant transgenic mice expressing a GH agonist (E117L), dwarf transgenic mice expressing a GH antagonist (G119K), and dwarf mice devoid of the GH receptor/binding protein (GHR/BP). In the E117L transgenic mice, the number and distribution of pituitary GH-immunoreactive cells were unchanged from nontransgenic littermate controls; an ultrastructural examination revealed typical, densely granulated somatotrophs. In contrast, the pituitaries of the G119K mice contained both moderately granulated somatotrophs and a sparsely granulated (SG) population with well-developed synthetic organelles and a distinct juxtanuclear globular GH-staining pattern. GHR/BP-deficient mice exhibited a marked reduction in the intensity of cytoplasmic GH immunoreactivity; however, prominent GH staining in the juxtanuclear Golgi was seen. GH-immunoreactive cells were increased in number, and the reticulin network pattern was distorted; stains for proliferating cell nuclear antigen confirmed mild hyperplasia. Electron microscopy showed that the somatotrophs were hyperactive SG cells with prominent endoplasmic reticulum membranes, large Golgi complexes, and numerous mitochondria. These findings are consistent with synthetic and secretory hyperactivity in pituitary somatotrophs due to the reduced GH feedback regulation. The changes are most striking in animals that are devoid of GHR/BP and less marked in animals expressing a GH antagonist; both models had reduced insulin-like growth factor-I levels, but the more dramatic change in the GHR/BP animals can be explained by abrogated GH signaling. This represents the first evidence of direct GH feedback inhibition on pituitary somatotrophs, which may have implications for the use of GH analogs in different clinical settings.

Basic Fibroblast Growth Factor Expression by Two Prolactin and Thyrotropin-Producing Pituitary Adenomas.

We investigated the expression of basic fibroblast growth factor (bFGF) in an aggressive type of PRL and TSH-producing pituitary adenoma. Immunocytochemistry and electron microscopy were used to characterize the tumors removed from two patients. Immunoassays were used to measure hormone and bFGF levels in vitro and in vivo. Reverse transcription-polymerase chain reaction (RT-PCR) was used to detect bFGF mRNA expression by these tumors. Morphologically, these tumors were characterized by an unusual plurihornal pattern with expression of PRL and TSH and the ultrastructural characteristics of the silent subtype 3 adenoma; in addition, both adenomas displayed marked interstitial fibrosis. bFGF was measurable in the circulation of these patients ranging from 7.5–20.5 pg/mL (normal<1 pg/mL). bFGF concentrations were reduced following surgical adenomectomy. bFGF in culture media was present in concentrations of 197–387 pg/24h/105 cells. bFGF mRNA expression was identified in both adenomas examined. bFGF levels were unaltered in the culture media and in the serum of patients following GnRH and TRH treatment. In conclusion, the expression of bFGF by these plurihormonal pituitary adenomas suggests the possiblity that it may play a role in the development of fibrosis and tumor cell proliferation of this unusual type of pituitary neoplasm.

IGF-I and testosterone levels as predictors of bone mineral density in healthy, community-dwelling men

objectiveu2002 Age‐related decline in IGF‐I and gonadal hormones have been postulated to play an important role in the pathogenesis of age‐related bone loss in men. In this cross‐sectional study, the relation between serum IGF‐I and gonadal hormones with bone mineral density (BMD) was examined in community‐dwelling men.

Inhibition of the sodium/potassium ATPase impairs N-glycan expression and function

Aberrant N-linked glycans promote the malignant potential of cells by enhancing the epithelial-to-mesenchymal transition and the invasive phenotype. To identify small molecule inhibitors of N-glycan biosynthesis, we developed a chemical screen based on the ability of the tetravalent plant lectin L-phytohemagglutinin (L-PHA) to bind and crosslink surface glycoproteins with beta1,6GlcNAc-branched complex type N-glycans and thereby induce agglutination and cell death. In this screen, Jurkat cells were treated with a library of off-patent chemicals (n = 1,280) to identify molecules that blocked L-PHA-induced death. The most potent hit from this screen was the cardiac glycoside (CG) dihydroouabain. In secondary assays, a panel of CGs was tested for their effects on L-PHA-induced agglutination and cell death. All of the CGs tested inhibited L-PHA-induced death in Jurkat cells, and the most potent CG tested was digoxin with an EC(50) of 60 +/- 20 nmol/L. Digoxin also increased the fraction of some concanavalin A-binding N-glycans. Using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, digoxin specifically increased GlcNAc(1)Man(3)GlcNAc(2)Fuc(1) and GlcNAc(2)Man(3)GlcNAc(2)Fuc(1) oligosaccharides demonstrating an impairment of the N-glycan pathway. Consistent with this effect on the N-glycan pathway, digoxin inhibited N-glycosylation-mediated processes of tumor cell migration and invasion. Furthermore, digoxin prevented distant tumor formation in two mouse models of metastatic prostate cancer. Thus, taken together, our high throughput screen identified CGs as modifiers of the N-glycan pathway. These molecules can be used as tools to better understand the role of N-glycans in normal and malignant cells. Moreover, these results may partly explain the anticancer effect of CGs in cardiovascular patients.

Cytoplasmic staining of erbB-2 but not mRNA levels correlates with differentiation in human thyroid neoplasia

Amplification and overexpression of the erbB‐2 proto‐oncogene in human carcinomas may have prognostic significance. Its role in thyroid carcinoma is controversial. We investigated human thyroid tumours for erbB‐2 gene amplification, activating mutations in the transmembrane domain, quantitative mRNA expression and protein expression.