Maria Melachrinou

Proliferating cell nuclear antigen immunoreactivity in human central nervous system neoplasms.

SummaryFormalin-fixed, paraffin-embedded surgical specimens from 140 primary human central nervous system tumors, including 51 meningiomas, 26 astrocytomas, 26 anaplastic astrocytomas, 9 glioblastomas, 1 gliosarcoma, 8 oligodendrogliomas, 5 ependymomas, 2 subependymomas, 9 medulloblastomas, and 3 paragangliomas, were immunostained using a streptavidin/peroxidase method and the PC10 monoclonal antibody, which recognizes an epitope on the proliferating cell nuclear antigen (PCNA). The following PCNA labeling index (LI) mean values were found for the above neoplasms: meningiomas, 3.80±7.35%; astrocytomas, 0.65±1.03%; anaplastic astrocytomas, 8.46±7.95%; glioblastomas, 10.26±11.21; gliosarcoma, 46.34%; oligodendrogliomas, 2.31±3.59%; ependymomas, 1.12±2.10%; medulloblastomas, 23.91±11.95%; and paragangliomas, 2.07±1.86%. Collectively, our findings indicate that while benign central nervous system tumors generally have low PCNA LI values, consistent over-expression of PCNA epitopes was noted in some examples, especially in a number of meningiomas. Among the malignant neuroectodermal tumors, medulloblastomas were found to have the highest PCNA LI values, corresponding to their histological grade of malignancy, and malignant glial tumors generally displayed significantly higher PCNA LI values, than their benign counterparts. Although in our study mean PCNA LI values seemed to reflect histological grading, large discrepancies were noted in all tumor groups. Our data, therefore, suggest than PCNA immunoreactivity can not be considered reliable for predicting the prognosis of the disease in individual cases.

Adipokine Serum Levels Are Related to Liver Histology in Severely Obese Patients Undergoing Bariatric Surgery

BackgroundLeptin, adiponectin, and resistin are adipokines linked to the development of insulin resistance, which plays a central role in the pathogenesis of nonalcoholic fatty liver disease (NAFLD). We aimed to define adipokine serum levels in severely obese patients undergoing bariatric surgery and to correlate these with anthropometric and metabolic variables, liver function tests, and histopathological parameters of NAFLD and nonalcoholic steatohepatitis (NASH).MethodsSurgical liver biopsies were obtained from 50 bariatric patients with no history of liver disease or significant alcohol consumption. Serum leptin, adiponectin, and resistin levels were measured, and histology was assessed using Brunt’s and Kleiner’s scoring systems.ResultsWaist/hip ratio was significantly higher in men (p = 0.0001), and leptin (p = 0.036) and adiponectin (p = 0.0001) serum levels were higher in women. Forty-one of 50 patients (82%) had histological NAFLD, including 10 (20%) with NASH. Nine patients (18%) had normal liver histology (obese control subgroup). In NAFLD patients, serum adiponectin was negatively correlated with activity grade and fibrosis stage, resistin was negatively correlated with steatosis grade (p = 0.033), while leptin was not related to histology. Leptin/adiponectin ratio showed positive association with stage (p = 0.044). In the subgroup of NASH patients, adiponectin was negatively correlated only with stage (p = 0.01), while there was no correlation between leptin, resistin, or leptin/adiponectin and histology.ConclusionsSerum adiponectin and resistin levels are related to liver histology in bariatric patients and may be indicative of the histological severity of NAFLD and the extent of hepatic steatosis, respectively. Serum leptin levels are not informative of underlying liver histology in severely obese patients.

Inverse expression of estrogen receptor-β and nuclear factor-κB in urinary bladder carcinogenesis

Objectives:  To investigate the expression of nuclear factor‐κB (NF‐κB) and estrogen receptor‐β (ER‐β) signalling pathways in bladder urothelial carcinoma according to clinicopathological features, in order to elucidate their role during carcinogenesis.

Expression of CD44 protein in renal cell carcinomas: association with p53 expression

CD44 is an adhesion molecule involved in cell-to-cell and cell-to-matrix interactions. Recent evidence indicates a role of CD44 in tumor growth and metastatic potential of tumor cells. Moreover, it is widely known that the p53 tumor suppressor gene controls cell proliferation and loss of its normal function may lead to carcinogenesis. To investigate the role of these biomarkers in renal cancer, we analyzed the immunohistochemical distribution of CD44s expression on formalin fixed paraffin embedded tissue from 67 renal cell carcinomas and correlated with clinicopathologic parameters as well as with p53 suppressor gene expression. The monoclonal antibodies CD44 and p53 were applied to the tissues using the streptavidin biotin peroxidase method after microwave antigen retrieval. For CD44 and p53 more than 10% membranous and 5% nuclear staining, respectively, were estimated as positive. CD44s membranous immunoreactivity was detected in 24/67 tumors (35%) and mostly in carcinomas of clear/granular cell type. Nine tumors expressed nuclear immunoexpression of p53 protein (13.4%). Statistically significant correlation was noted between CD44 expression and nuclear grade (P < 0.001), tumor stage (P < 0.001), vascular invasion (P < 0.05) and p53 expression (P < 0.01). These results suggest that CD44s and p53 are markers of tumor progression in renal cell cancer.

Epigenetic modifications in cutaneous malignant melanoma: EZH2, H3K4me2, and H3K27me3 immunohistochemical expression is enhanced at the invasion front of the tumor.

Abstract:Cancer stem cells and the misregulation of epigenetic modifications have been identified to possess a determinative role in carcinogenesis. The purpose of this study was to investigate the expression profile of EZH2 and H3K4me2 and H3K27me3, which constitute stem cell-like “bivalent” domains, in cutaneous malignant melanoma. A comparative analysis of their immunohistochemical expression between the invasion front (IF) and the inner tumor mass was also evaluated. Immunohistochemical methodology was performed on sections of 89 melanoma lesions from 79 patients. The 3 markers studied were identified in the cell nuclei of melanoma cells, nevus cells, and normal epidermal keratinocytes. A specific distribution pattern of H3K4me2 and H3K27me3 was found, as stronger levels were localized at the IF of the tumor (P = 0.034 and P < 0.01, respectively). In general, H3K4me2 and H3K27me3 levels were lower in metastatic with respect to primary melanoma cases (P = 0.0065 and P = 0.027, respectively). Advanced melanoma demonstrated significantly lower H3K4 immunohistochemical expression than did cases of lowest Clark level (I) (P = 0.038) or low Breslow depth (⩽1 mm; P < 0.001). Furthermore, EZH2 expression in melanoma cells was higher compared with that in nevus cells (P = 0.02). A positive correlation between EZH2–H3K27me3 (P = 0.03) and H3K4me2–H3K27me3 (P < 0.01) in melanoma cells was also found. Our results suggest the possibility that combined immunohistochemical expression of EZH2, H3K4me2, and H3K27me3 might identify cancer cells with potential stem cell properties, particularly at the IF of this malignancy. This hypothesis should be further investigated, as many of the epigenetic changes are reversible via pharmacologic manipulations and new therapies, overpassing the resistance of advanced melanoma, may be developed.

CASE REPORT: Neuromuscular and Vascular Hamartoma of the Small Bowel

In 1982, Fernando and McGovern described for the first time an hamartomatous entity of the small intestine that consisted of fascicles of smooth muscle derived from the muscularis mucosae, bundles of unmyelinated nerve fibers with ganglion cells, and hemangiomatous vessels (1). They designated it a neuromuscular and vascular hamartoma. Approximately nine cases with similar microscopic features have been reported to date (2–5). Shepherd and Jass (3) have suggested that neuromuscular and vascular hamartoma does not represent a distinct entity, because identical pathological features may be seen in inflammatory bowel disease, predominantly Crohn’s disease. We report the tenth case of this rare hamartomatous condition, occuring in a 40-year-old man with no previous history of inflammatory bowel disease.

Expression of ERβ and Its Co-Regulators p300 and NCoR in Human Transitional Cell Bladder Cancer

Objective: Several data support a possible role of estrogens in bladder carcinogenesis, mediated mainly through estrogen receptor-β (ERβ). We study the expression of ERβ and its co-regulators p300 and nuclear co-repressor (NCoR) in patients with bladder cancer. Patients and Methods: One hundred and eleven consecutive patients (74 males and 37 females), aged 23–90 years (mean 70 ± 10) diagnosed with transitional cell bladder cancer were included in this study. The control group consisted of 29 patients that underwent transurethral prostatectomy and consented to simultaneous bladder biopsies. Immunohistochemical studies took place on formalin-fixed, paraffin-embedded sections from the TUR (transurethral resection) specimens. We studied the expression of ERβ, p300 and NCoR.χ2 test was used to evaluate the relationship between the histological grade and ERβ expression, grade and co-regulators expression and grade and gender. Spearman rank correlation coefficient (r) was used in order to estimate the direction and strength of correlations between histological grade and ERβ-p300-NCoR expressions. The Cochran-Armitage test for trend was applied in order to examine possible trends across the ordered levels of histological grade. Results: ERβ was more frequently expressed in the nucleus of normal bladder epithelium compared to malignant bladder epithelium with statistical significant association (r = –0.25, p = 0.003). The p300 was expressed only in the nucleus of bladder cancer cells and a positive correlation between molecular expression and cancer progression was demonstrated (r = 0.55, p < 0.001). NCoR immunostaining was demonstrated in the nuclei of bladder cells. Nuclear staining was significantly higher in normal tissue than in cancer cells (r = –0.33, p < 0.001), with negative correlation. Furthermore, its expression in grade I tumors was significantly higher than in grade II (r = –0.46, p < 0.001) and grade III tumors (r = –0.51, p < 0.001). Thus, like ERβ, NCoR expression in bladder epithelium decreased during cancer progression and loss of cell differentiation. There was no correlation between the levels of expression of the three proteins in normal bladder epithelium, but there was an inverse correlation between the nuclear expression of ERβ and p300 in carcinomas (r = –3.88, p = 0.042). Statistical significant association was established when correlating ERβ expression with NCoR expression (r = 0.273, p = 0.005), while co-regulators’ nuclear expression did not correlate with each other (p > 0.05). Conclusions: In bladder carcinogenesis, we demonstrated inhibition in the expression of ERβ and its co-repressor NCoR as well as increased expression of the co-activator p300.

Gastric ulcers and risk for cancer. Is follow-up necessary for all gastric ulcers?

The aim of this study was to determine the accuracy of initial endoscopy combined with histology and to define whether there is a point in following‐up all gastric ulcers until complete healing. We have studied all patients with gastric ulcers documented at endoscopy during a 6‐year period. Ulcers were macroscopically characterised as benign or suspicious for malignancy, and biopsies were taken. A follow‐up endoscopy and histology was performed 4–6 weeks and 3 months after an anti‐ulcer treatment. Resistant ulcers were treated surgically. All patients were followed‐up clinically and endoscopically for a year after complete ulcer healing. 802 patients with gastric ulcers were enrolled. At initial endoscopy, 732 ulcers (91.3%) were macroscopically characterised as benign and 70 ulcers (8.7%) as suspicious for malignancy. In the group of endoscopically benign ulcers, only one (0.1%) had malignancy detected by biopsy in the first examination. None of these ulcers turned out to be malignant on subsequent examinations. From the suspicious for malignancy ulcers, 20 (28.6%) were proven to be malignant. Endoscopy may recognise with great accuracy benign ulcers, but it overestimates the malignant ones. The cost‐benefit of serial follow‐up endoscopies should be re‐evaluated in ulcers that appear benign, and biopsies are negative at the initial examination.

Determination of Plasma Cell Secreting Potential as an Index of Maturity of Myelomatous Cells and a Strong Prognostic Factor

According to the widely accepted myeloma staging system, the bulk of paraprotein is the main determinant of disease stage. However, myelomatous plasma cells differ considerably in their ability to synthesize and secrete monoclonal paraprotein. We determined plasma cell secreting potential (PCSP) as the amount of M-component, divided by the percentage of marrow plasmacytic infiltration, in 240 patients with myeloma, and correlated our results with chain isotype, plasma cell morphology, severity of bone disease, well-recognized prognostic factors, such as serum LDH, CRP, albumin and β 2 -microglobulin, treatment response and overall survival. PCSP was higher in IgG than in other myeloma types, and was an almost constant parameter for each individual patient, in 134/166 cases. A >10% decrease of PCSP in 26 patients was associated with disease aggressiveness and treatment failure. Patients with MGUS had significantly higher PCSP than those with myeloma of the same chain type. Higher PCSP was associated with stage I, absence of Bence-Jones proteinuria and indolent forms of disease with lower proliferating cell nuclear antigen (PCNA) positivity, serum LDH, α 2 -globulins, CRP and β 2 -microglobulin and higher albumin levels. Conversely, patients with immature/plasmablastic morphology and those with severe bone disease had lower PCSP. Good responders to treatment had significantly higher PCSP than moderate and poor responders and PCSP was strongly correlated with overall survival in IgG and IgA myeloma. In conclusion, PCSP reflects the maturation status of myelomatous cells and therefore can be used as a prognostic factor, since patients with high secreting potential represent a lower malignancy group, in comparison to those with a low secreting potential.

Experimental studies in the bronchial circulation. Which is the ideal animal model

BACKGROUND The importance of the role of bronchial arteries is notable in modern days thoracic surgery. The significance of their anastomoses with adjusted structures has not yet been sufficiently rated, especially in cases of haemoptysis, heart-lung transplantations and treatment of aneurysms of the thoracic aorta. The need of a thorough study is more relevant than ever and appropriate laboratory animals are required. METHODS We review the literature in order to highlight the ideal experimental animal for the implementation of pilot programs relative to the bronchial circulation. A comparative analysis of the anatomy of the bronchial arterial system in humans along with these of pigs, dogs, rats, and birds, as being the most commonly used laboratory animals, is presented in details. RESULTS The pig has the advantage that the broncho-oesophageal artery usually originates from the aorta as a single vessel, which makes the recognition and dissection of the artery easy to perform. In dogs, there is significant anatomical variation of the origin of the bronchial arteries. In rats, bronchial artery coming from the aorta is a rare event while in birds the pattern of the bronchial artery tree is clearly different from the human analog. CONCLUSIONS The pig is anatomically and physiologically suited for experimental studies on the bronchial circulation. The suitable bronchial anatomy and physiology along with the undeniable usefulness of the pig in experimental research and the low maintenance cost make the pig the ideal model for experiments in bronchial circulation.