Ioannis Papaconstantinou

Expression of microRNAs, miR-21, miR-31, miR-122, miR-145, miR-146a, miR-200c, miR-221, miR-222, and miR-223 in patients with hepatocellular carcinoma or intrahepatic cholangiocarcinoma and its prognostic significance.

MicroRNAs are a class of non‐coding molecules found to regulate a variety of cellular functions in health and disease. Dysregulation of microRNAs is involved in liver disease, especially hepatocarcinogenesis. Since primary hepatic malignancies are typically characterized by late diagnosis, frequent recurrence, and poor response to adjuvant therapy, there is a need for the discovery of novel biomarkers in order to achieve earlier diagnosis, predict tumor aggressiveness and response to adjuvant therapy. The purpose of this study is to evaluate the expression of certain microRNAs (miR‐21, ‐31, ‐122, ‐145, ‐146a, ‐ 200c, ‐221, ‐222 and ‐223) in patients with hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC), as well as to assess their prognostic significance. Micro‐RNA expression was assessed by reverse transcription and real‐time PCR (RT‐PCR). Clinicopathological data and survival rates were retrieved and analyzed. According to our results, miR‐21, miR‐31, miR‐122, miR‐221, miR‐222 were significantly up‐regulated in HCC tissues, whereas miR‐145, miR‐146a, miR‐200c, and miR‐223 were found to be down‐regulated. Concerning ICC samples, miR‐21, miR‐31, and miR‐223 were found to be over‐expressed, whereas miR‐122, miR‐145, miR‐200c, miR‐221, and miR‐222 were down‐regulated. Additionally, expression of miR‐21, miR‐31, miR‐122, and miR‐221 in HCC correlated with cirrhosis, while miR‐21 and miR‐221 associated with tumor stage and poor prognosis. In ICC tissues, miR‐21, miR‐31, and miR‐223 were found to be over‐expressed, but no correlation with clinicopathological features was found.

Circulating MicroRNA in inflammatory bowel disease

BACKGROUND MicroRNAs (miRNAs) consist of a group of small noncoding RNAs that partially regulate gene expression. We investigated the expression patterns of commonly deregulated miRNAs in Crohns disease (CD) and ulcerative colitis (UC) in peripheral blood samples of inflammatory bowel disease patients. PATIENTS AND METHODS This study consisted of 128 CD and 88 UC patients, as well as 162 healthy controls. The expression patterns of the miRNA species were quantitatively assayed using reverse transcription and real-time RT-PCR. Stem-loop complementary DNAs (cDNAs) were synthesized using looped reverse transcription primers specific for each miRNA. RESULTS MiR-16, miR-23a, miR-29a, miR-106a, miR-107, miR-126, miR-191, miR-199a-5p, miR-200c, miR-362-3p and miR-532-3p were expressed at significantly higher levels in the blood from patients with CD compared with the healthy controls. No significant differences were observed when the CD patients were classified according to disease location and phenotype. In the UC cases three miRNAs (miR-16, miR-21, miR-28-5p, miR-151-5p, miR-155 and miR-199a-5p) were significantly increased compared to healthy controls. miR-155 was the most highly expressed of the UC-associated miRNA in blood samples. CONCLUSIONS Our results suggest that several miRNAs could distinguish CD from UC by real-time PCR. This further highlights the putative role of miRNAs as contributors to IBD pathogenesis. They may help develop new non-invasive biomarkers to distinguish UC and CD.

Expression of microRNAs in patients with pancreatic cancer and its prognostic significance.

Objectives Investigation of expression profile of well-established microRNAs in pancreatic adenocarcinoma, and its correlation with clinicopathological factors. Methods Eighty-eight samples of ductal pancreatic adenocarcinoma and 98 control samples were analyzed by real-time polymerase chain reaction for miR-21, miR-31, miR-122, miR-145, miR-146a, miR-155, miR-210, and miR-222 expressions. The results were normalized and then statistically analyzed using nonparametric statistical tests. Results According to our results, miR-21, miR-155, miR-210, miR-221, and miR-222, were overexpressed in diseased tissues than in the control samples, whereas miR-31, miR-122, miR-145, and miR-146a were underexpressed. Additionally, the expressions of miR-21 and miR-155 were associated with tumor stage and poor prognosis. Conclusions The tumorigenic role of miR-21 and miR-155 was confirmed, whereas down-regulation of miR-31, miR-145, and miR-146a, in dispute with current literature, renders necessary the revision of use of microRNAs as biological markers.

Survivin -31G/C promoter polymorphism and sporadic colorectal cancer

IntroductionSurvivin is an apoptotic inhibitor, plays an important role in cell cycle regulation, and may be involved in the development and progression of cancer. A common polymorphism at the survivin gene promoter (-31 G/C) has been shown to influence survivin expression and the risk for cancer.AimThe aim of the present study was to investigate whether this polymorphism could be involved in the sporadic colorectal cancer (CRC) development, prognosis, and survival.Materials and methodsThe -31G/C polymorphism of survivin promoter was analyzed by polymerase chain reaction (PCR) restriction fragment length polymorphism method in biopsies from 312 patients with sporadic CRC and 362 healthy individuals. Survivin messenger RNA (mRNA) expression in CRC tissues was detected by quantitative reverse transcriptase PCR.Results and discussionThe genotype frequencies for -31GG, -31GC, and -31CC were 21.79%, 41.99%, and 36.22% in CRC patients and 33.98%, 45.03%, and 20.99% in healthy subjects, respectively. The frequencies of the survivin -31C allele and CC genotype were significantly higher in CRC patients than in healthy subjects (p < 0.0001). Homozygotes for the -31CC survivin genotype, expressed 1.6-fold higher mRNA levels of survivin compared to cases with the -31GG and -31GC genotypes.ConclusionThe -31CC genotype of survivin promoter is associated with CRC and may be a risk factor for CRC.

Association between mutations in the CARD15/NOD2 gene and colorectal cancer in a Greek population

Epidemiological observations suggest that cancer arises from chronically inflamed tissues. Inflammatory bowel disease (IBD) is a typical example since patients with longstanding IBD are at increased risk for development of colorectal cancer (CRC). Therefore, genetic factors predisposing to or implicated in the chronic inflammatory process in IBD may simultaneously predispose to CRC. Recently CARD15/NOD2 has been associated with IBD, which further strengthens the notion that the inflammatory response plays a crucial role in this disease. Several mutations have been identified in the CARD15/NOD2 gene, which appear with significantly higher frequency in patients with IBD. In this report, we have examined the frequency of the 3 major mutations R702W, G908R and 3020insC of the CARD2/NOD2 gene in a series of 104 consecutive Greek patients with sporadic colorectal cancer and 100 healthy individuals. The frequency of all the mutations was significantly elevated compared to the control population (R702W, OR=5.00, p=0.023; G908R, OR=2.78, p=0.025; 3020insC, OR=2.44, p=0.017). Patients with advanced stage tumors were more frequently carriers of at least 1 variant in the CARD15/NOD2 gene (p=0.009). Our results suggest that CARD2/NOD2 may be a genetic factor that predispose to sporadic colorectal cancer.

Assessment of JC polyoma virus in colon neoplasms.

PURPOSEResearch data have recently emphasized an intriguing association of JC polyoma virus with colon carcinogenesis. Tumorigenicity of JC virus is attributed to the T-antigen of its Mad-1 variant. Controversy arose when another research group did not confirm this association. The purpose of this study was to detect JC virus in a series of colon neoplasms from Greek patients.METHODSA nested polymerase chain reaction assay was used to detect JC virus in 80 cancerous, 25 adenomatous specimens of large bowel, and 20 colonoscopic biopsy samples from normal patients without colorectal neoplasia. Quantitation of JC virus DNA was performed by real-time polymerase chain reaction.RESULTSJC polyoma virus nucleotide sequence was detected in 61 percent of colon adenocarcinomas and in 60 percent of adenomas, at a viral load of 9 × 103 to 20 × 103 copies/µg DNA. Adjacent normal mucosa in 35 positive colon adenocarcinoma specimens, and normal mucosa from six patients of the control group, had low viral loads (50–450 copies/µg DNA).CONCLUSIONSJC polyoma virus genome is present in colon neoplasms. JC virus detection in adenomas at comparable viral loads to malignant tumors suggests its implication at early steps of colonic carcinogenesis. Taking into consideration other published data, infection of colonic epithelium with JC virus might be a prime candidate for a role in chromosomal and genomic instability.

The role of microRNAs in liver cancer.

Hepatocellular carcinoma and cholangiocarcinoma constitute the majority of primary malignant tumors located in the liver, with hepatocellular carcinoma accounting for approximately 80% of these tumors and cholangiocarcinoma representing the remaining 20%. Both are aggressive malignancies, heterogeneous in terms of biological activities and clinical behavior, with dismal outcomes and an increasing incidence worldwide. Radical surgical resection remains the gold standard to date, as adjuvant therapeutic modalities have failed to show a consistent and adequate curative response. However, radical surgical resection is not feasible in most of the patients with such tumors, as tumor size or functional status of the parenchyma does not permit extended hepatic resection. In addition, patients who undergo curative resection often have a high rate of relapse. Multimodal therapeutic approaches, such as the combination of invasive methods (surgical resection, radiofrequency ablation, and two-step or three-step procedures with intermittent portal vein embolization) with interferon-&agr;, systemic chemotherapy, or transarterial catheter embolization, may prolong survival in some patients, but have, however, failed to demonstrate satisfactory results. Therefore, an obvious need emerges for the discovery of new biomarkers to understand the events leading to hepatocarcinogenesis, to relate different phenotypes with differences in clinical behavior and prognosis, and, if possible, to predict response rates to adjuvant therapeutic modalities or, furthermore, to establish novel mechanism-based treatments for hepatic tumors.

A review on the role of microRNA in biology, diagnosis, and treatment of pancreatic adenocarcinoma.

Objectives MicroRNAs are molecules implicated in RNA-RNA interaction, playing a role in cell proliferation and differentiation, as well as in carcinogenesis. Knowledge on their biological features is necessary to understand their role in phenotypic characteristics of pancreatic adenocarcinoma. Methods Review of current literature concerning mechanisms of action, studying methods, implementations, and preclinical trials on pancreatic adenocarcinoma. Results More than 20 microRNAs have been identified, being involved in pancreatic adenocarcinoma biology, affecting tumor growth, metastatic potential, and chemosensitivity. Combinations of microRNAs can be used to differentiate between pancreatic adenocarcinoma and other pancreatic pathologies, as well as to assess prognosis. Manipulations of microRNAs can decrease the rate of growth or reinstall chemosensitivity to certain chemotherapeutic agents. Conclusions The field of microRNAs promises novel diagnostic and therapeutic tools in the management of pancreatic adenocarcinoma.

Inflammatory pseudotumor associated with Mycobacterium tuberculosis infection

BACKGROUND Inflammatory pseudotumor is a relatively rare entity; originally identified in the lung, it has been described in multiple extrapulmonary anatomic locations. CASE REPORT We report on the unusual case of an inflammatory pseudotumor associated with Mycobacterium tuberculosis infection, which was initially mistaken for a renal malignancy both in clinical and radiological settings. We additionally present three brief reviews concerning: (1) infectious agents postulated to induce morphological changes of an inflammatory pseudotumor; (2) mycobacterial pseudotumors; and (3) distinction from inflammatory myofibroblastic tumors of the renal pelvis. CONCLUSIONS The present case highlights the diagnostic importance of PCR-based detection of mycobacterial DNA in granulomatous tissue responses. It is of crucial importance that clinicians are aware of this unusual manifestation of mycobacterial infection to ensure that pertinent laboratory evaluation is employed and appropriate treatment is administered in order to avoid potential clinical implications.

Synchronous gastric adenocarcinoma and gastrointestinal stromal tumor (GIST) of the stomach: A case report

Gastrointestinal stromal tumors (GISTs) are rare mesenchymal neoplasms of the gastrointestinal tract (1%), and stomach is the most common location involved. However, the co-existence of gastric adenocarcinoma and GIST is very rare. A case of an 80-year-old male with a simultaneous presentation of a gastric adenocarcinoma and GIST is presented. Various hypotheses have been proposed in order to explain this rare simultaneous development, but even though its cause has not been proven yet.