Nikolaos V. Michalopoulos

Prof. Nikolaos V. Michalopoulos

Department of Surgery, Medical School, University of Athens, Athens, Greece

Research Focus & Metrics

Academic Career Length

20Years (2007-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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DSDimitrios Stefanoudakis
Dimitrios Stefanoudakis
Maximos FrountzasMaximos Frountzas
Maximos Frountzas
DIMITRIOS SCHIZASDIMITRIOS SCHIZAS
DIMITRIOS SCHIZAS
Nikolaos V. MichalopoulosNikolaos V. Michalopoulos
Nikolaos V. Michalopoulos
ADAlexandra Drakaki
Alexandra Drakaki
KTKonstantinos G Toutouzas
Konstantinos G Toutouzas
The present review demonstrates the major tumor suppressor genes, including TP53, CDKN2A and SMAD4, associated with pancreatic cancer. Each gene’s role, prevalence and impact on tumor development and progression are analyzed, focusing on the intricate molecular landscape of pancreatic cancer. In addition, this review underscores the prognostic significance of specific mutations, such as loss of TP53, and explores some potential targeted therapies tailored to these molecular signatures. The findings highlight the importance of genomic analyses for risk assessment, early detection and the design of personalized treatment approaches in pancreatic cancer. Overall, this review provides a comprehensive analysis of the molecular intricacies of pancreatic tumors, paving the way for more effective and tailored therapeutic interventions.

8 December 2023 in Cancers
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IAIoanna Akrida
Ioanna Akrida
Nikolaos V. MichalopoulosNikolaos V. Michalopoulos
Nikolaos V. Michalopoulos
MLMARIA LAGADINOU
MARIA LAGADINOU
MPMARIA Papadoliopoulou
MARIA Papadoliopoulou
IMIoannis Maroulis
Ioannis Maroulis
Francesk MulitaFrancesk Mulita
Francesk Mulita
Sentinel lymph node biopsy (SLNB) has become the standard of care for clinically node-negative breast cancer and has recently been shown by clinical trials to be also feasible for clinically node-positive patients treated with primary systemic therapy. The dual technique using both radioisotope (RI) and blue dye (BD) as tracers for the identification of sentinel lymph nodes is considered the gold standard. However, allergic reactions to blue dye as well as logistics issues related to the use of radioactive agents, have led to research on new sentinel lymph node (SLN) tracers and to the development and introduction of novel techniques in the clinical practice. Indocyanine green (ICG) is a water-soluble dye with fluorescent properties in the near-infrared (NIR) spectrum. ICG has been shown to be safe and effective as a tracer during SLNB for breast cancer and accumulating evidence suggests that ICG is superior to BD and at least comparable to RI alone and to RI combined with BD. Thus, ICG was recently proposed as a reliable SLN tracer in some breast cancer clinical practice guidelines. Nevertheless, there is lack of consensus regarding the optimal role of ICG for SLN mapping. Specifically, it is yet to be determined whether ICG should be used in addition to BD and/or RI, or if ICG could potentially replace these long-established traditional SLN tracers. This article is an updated overview of somerecent studies that compared ICG with BD and/or RI regarding their accuracy and effectiveness during SLNB for breast cancer.

5 July 2010 in BMC Cancer
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FZFlora Zagouri
Flora Zagouri
Theodoros N. SergentanisTheodoros N. Sergentanis
Theodoros N. Sergentanis
ANAfrodite Nonni
Afrodite Nonni
CPChristos Papadimitriou
Christos Papadimitriou
Nikolaos V. MichalopoulosNikolaos V. Michalopoulos
Nikolaos V. Michalopoulos
GZGeorge C Zografos
George C Zografos
Background: Hsp90 (heat shock protein90) is a chaperone protein essential for preserving and regulating the function of various cellular proteins. Elevated Hsp90 expression seems to be a trait of breast cancer and may be an integral part of the coping mechanisms that cancer cells exhibit vis-à-vis stress. This manuscript tries to examine the immunohistochemical expression of Hsp90 all along the continuum of breast ductal lesions encompassing ductal hyperplasia without atypia (DHWithoutA), atypical ductal hyperplasia (ADH), ductal carcinoma in situ (DCIS) and invasive ductal carcinoma (IDC). Methods: Tissue specimens were taken from 30 patients with DHWithoutA, 31 patients with ADH, 51 with DCIS and 51 with IDC. Immunohistochemical assessment of Hsp90 was performed both in the lesion and the adjacent normal breast ducts and lobules; the latter serving as control. Concerning Hsp90 assessment the percentage of positive cells and the intensity were separately analyzed. Subsequently, the Allred score was calculated. Post hoc analysis on the correlations between Hsp90 Allred score and possible predictors (grade, nodal status, tumor size, ER Allred score, PR Allred score, c-erbB-2 status and triple negative status) was conducted in IDC. Results: Hsp90 exhibited mainly cytoplasmic immunoreactivity. Hsp90 Allred score exhibited an increasing trend along the continuum of breast ductal lesions (Spearman's rho = 0.169, p = 0.031). Compared to the adjacent normal ducts and lobules, no statistically significant differences were noted in DHwithoutA, ADH and DCIS. Hsp90 expression (intensity, positive cells, Allred score) was higher in IDC, compared to the adjacent normal tissue. Higher Hsp90 expression was observed in grade 2/3 IDCs (borderline association) and tumors of larger size. At the univariable analysis, higher Hsp90 expression was associated with higher ER Allred score, PR Allred score and c-erbB-2 positivity in IDC. Triple-negative IDCs exhibited significantly lower Hsp90 expression. The multivariable logistic regression model revealed that between the three markers, solely ER Allred score and c-erbB-2 positivity were independently associated with higher Hsp90 expression in IDC. Conclusion: The above point to significant variability in Hsp90 expression with significant implications upon the effectiveness and limitations of anti-Hsp90 drugs.

8 May 2024 in Biomedicines
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TSTheodoros A Sidiropoulos
Theodoros A Sidiropoulos
Nikolas DovrolisNikolas Dovrolis
Nikolas Dovrolis
HKHector Katifelis
Hector Katifelis
Nikolaos V. MichalopoulosNikolaos V. Michalopoulos
Nikolaos V. Michalopoulos
PKPanagiotis Kokoropoulos
Panagiotis Kokoropoulos
Maria GazouliMaria Gazouli
Maria Gazouli
Pancreatic cancer (PC) ranks as the seventh leading cause of cancer-related deaths, with approximately 500,000 new cases reported in 2020. Existing strategies for early PC detection primarily target individuals at high risk of developing the disease. Nevertheless, there is a pressing need to identify innovative clinical approaches and personalized treatments for effective PC management. This study aimed to explore the dysbiosis signature of the fecal microbiota in PC and potential distinctions between its Intraductal papillary mucinous neoplasm (IPMN) and pancreatic ductal adenocarcinoma (PDAC) phenotypes, which could carry diagnostic significance. The study enrolled 33 participants, including 22 diagnosed with PDAC, 11 with IPMN, and 24 healthy controls. Fecal samples were collected and subjected to microbial diversity analysis across various taxonomic levels. The findings revealed elevated abundances of Firmicutes and Proteobacteria in PC patients, whereas healthy controls exhibited higher proportions of Bacteroidota. Both LEfSe and Random Forest analyses indicated the microbiome’s potential to effectively distinguish between PC and healthy control samples but fell short of differentiating between IPMN and PDAC samples. These results contribute to the current understanding of this challenging cancer type and highlight the applications of microbiome research. In essence, the study provides clear evidence of the gut microbiome’s capability to serve as a biomarker for PC detection, emphasizing the steps required for further differentiation among its diverse phenotypes.

16 December 2022 in World Journal of Emergency Surgery
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Belinda De SimoneBelinda De Simone
Belinda De Simone
FAFikri M. Abu-Zidan
Fikri M. Abu-Zidan
ECElie Chouillard
Elie Chouillard
SSSalomone Di Saverio
Salomone Di Saverio
MSMassimo Sartelli
Massimo Sartelli
Fausto CatenaFausto Catena
Fausto Catena
Background: The incidence of the highly morbid and potentially lethal gangrenous cholecystitis was reportedly increased during the COVID-19 pandemic. The aim of the ChoCO-W study was to compare the clinical findings and outcomes of acute cholecystitis in patients who had COVID-19 disease with those who did not. Methods: Data were prospectively collected over 6 months (October 1, 2020, to April 30, 2021) with 1-month follow-up. In October 2020, Delta variant of SARS CoV-2 was isolated for the first time. Demographic and clinical data were analyzed and reported according to the STROBE guidelines. Baseline characteristics and clinical outcomes of patients who had COVID-19 were compared with those who did not. Results: A total of 2893 patients, from 42 countries, 218 centers, involved, with a median age of 61.3 (SD: 17.39) years were prospectively enrolled in this study; 1481 (51%) patients were males. One hundred and eighty (6.9%) patients were COVID-19 positive, while 2412 (93.1%) were negative. Concomitant preexisting diseases including cardiovascular diseases (p < 0.0001), diabetes (p < 0.0001), and severe chronic obstructive airway disease (p = 0.005) were significantly more frequent in the COVID-19 group. Markers of sepsis severity including ARDS (p < 0.0001), PIPAS score (p < 0.0001), WSES sepsis score (p < 0.0001), qSOFA (p < 0.0001), and Tokyo classification of severity of acute cholecystitis (p < 0.0001) were significantly higher in the COVID-19 group. The COVID-19 group had significantly higher postoperative complications (32.2% compared with 11.7%, p < 0.0001), longer mean hospital stay (13.21 compared with 6.51 days, p < 0.0001), and mortality rate (13.4% compared with 1.7%, p < 0.0001). The incidence of gangrenous cholecystitis was doubled in the COVID-19 group (40.7% compared with 22.3%). The mean wall thickness of the gallbladder was significantly higher in the COVID-19 group [6.32 (SD: 2.44) mm compared with 5.4 (SD: 3.45) mm; p < 0.0001]. Conclusions: The incidence of gangrenous cholecystitis is higher in COVID patients compared with non-COVID patients admitted to the emergency department with acute cholecystitis. Gangrenous cholecystitis in COVID patients is associated with high-grade Clavien-Dindo postoperative complications, longer hospital stay and higher mortality rate. The open cholecystectomy rate is higher in COVID compared with non -COVID patients. It is recommended to delay the surgical treatment in COVID patients, when it is possible, to decrease morbidity and mortality rates. COVID-19 infection and gangrenous cholecystistis are not absolute contraindications to perform laparoscopic cholecystectomy, in a case by case evaluation, in expert hands. Graphical
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11 September 2007 in World Journal of Surgical Oncology
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FZFlora Zagouri
Flora Zagouri
Theodoros N. SergentanisTheodoros N. Sergentanis
Theodoros N. Sergentanis
DKDimitra Koulocheri
Dimitra Koulocheri
ANAfrodite Nonni
Afrodite Nonni
ABAggeliki Bousiotou
Aggeliki Bousiotou
GZGeorge C Zografos
George C Zografos
Background: Breast cancer is usually associated with metastases to lungs, bones and liver. Breast carcinoma metastasizing to the gallbladder is very rare.Case presentation: A 59-year-old woman presented with bilateral synchronous breast lesions. A palpable, retroareolar solid lesion of diameter equal to 5 cm was present in the right breast, and a newly developed, non-palpable lesion with microcalcifications (diameter equal to 0.7 cm) was present in the upper outer quadrant of the left breast. Modified radical mastectomy was performed on the right breast and lumpectomy after hook-wire localization was performed on the left breast, combined with lymph node dissection in both sides. The pathological examination revealed invasive lobular carcinoma grade II in the right breast and invasive ductal carcinoma grade I in the left breast. Chemotherapy, radiation therapy, trastuzumab and letrozole were appropriately administered. At her 18-month follow-up, the patient was free of symptoms; the imaging tests (chest CT, abdominal U/S, bone scan), biochemical tests, blood cell count and tumor markers were also normal. At the 20th month after surgery however, the patient developed symptoms of cholecystitis and underwent cholecystectomy. The histopathological examination revealed metastasis of the lobular carcinoma to the gallbladder.Conclusion: This extremely rare case confirms on a single patient the results of large series having demonstrated the preferential metastasis of lobular breast cancer to the gallbladder. Symptoms of cholecystitis should not be neglected in such patients, as they might indicate metastasis to the gallbladder.