António Dias Pereira

DNA methylation as an intermediate biomarker in colorectal cancer: modulation by folic acid supplementation.

Several studies have suggested that DNA hypomethylation is an early step in colorectal carcinogenesis. However, it is not clear at which stage in carcinogenesis this hypomethylation occurs, what promotes it, the extent to which it can be reversed and the consequences of such reversal in affecting tumour development. In an attempt to address some of these questions, we studied three groups of subjects with similar age and gender distributions: a group of 12 patients with colorectal carcinomas; a group of 12 patients with colorectal adenomas; and a group of eight healthy control subjects. Two experimental protocols were employed. In the first protocol, intrinsic DNA methylation was evaluated in neoplastic and in normal-appearing rectal mucosa of patients with colonic carcinomas or adenomas, compared with a group of healthy controls. In the second protocol, we examined, in a prospective and controlled fashion, the effect of folic acid supplementation (10 mg/day) on the degree of DNA methylation of rectal mucosa from those same patients after removal of the neoplasms. The degree of intrinsic DNA methylation was assessed on the basis of the capacity of the DNA isolates to serve as methyl acceptors in in vitro incubations that contained DNA methylase and [3H-methyl] S-adenosylmethionine. Intrinsic DNA methylation was significantly lower in carcinomas than in adenomas (P < 0.005). In addition, normal-appearing rectal mucosa from patients with carcinomas was significantly less methylated than in healthy controls (P < 0.005); the mean value found in the latter was also greater than the value observed in patients with adenomas, but not significantly so (P > 0.05). Patients with resected neoplasms who received folk acid supplementation for 6 months had a marked increase in the degree of intrinsic DNA methylation in the rectal mucosa (P < 0.002). Three months after cessation of treatment, DNA methylation decreased substantially (P < 0.05), but remained significantly greater than baseline values (P < 0.02). In contrast, DNA methylation values remained stable throughout the study in placebo-treated patients (P = 0.40). Our study demonstrates that global DNA hypomethylation occurs in normal rectal mucosa from patients with colorectal neoplasms as compared with controls, and that it was significantly reduced with pharmacological doses of folk add. It remains to be determined whether the risk of tumour recurrence is affected as well.

Risk factors for metabolic bone disease in Crohn's disease patients

Background: The aim was to evaluate the presence of metabolic bone disease (MBD) in patients with Crohns disease (CD) and to identify potential etiologic factors. Methods: The case–control study included 99 patients with CD and 56 controls with a similar age and gender distribution. Both groups had dual‐energy x‐ray absorptionmetry and a nutritional evaluation. Single nucleotide polymorphisms at the IL1, TNF‐&agr;, LT&agr;, and IL‐6 genes were analyzed in patients only. Statistical analysis was performed using SPSS software. Results: The prevalence of MBD was significantly higher in patients (P = 0.006). CD patients with osteoporosis were older (P < 0.005), small bowel involvement and surgical resections were more frequent (P < 0.005), they more often exhibited a penetrating or stricturing phenotype (P < 0.05), duration of disease over 15 years (P < 0.005), and body mass index (BMI) under 18.5 kg/m2 (P < 0.01) were more often found. No association was found with steroid use. Patients with a Z‐score < −2.0 more frequently had chronic active disease (P < 0.05). With regard to diet, low vitamin K intake was more frequent (P = 0.03) and intake of total, monounsaturated, and polyunsaturated fat was higher in patients with Z‐score < −2.0 (P < 0.05). With respect to genetics, carriage of the polymorphic allele for LT&agr;252 A/G was associated with a higher risk of osteoporosis (P = 0.02). Regression analysis showed that age over 40 years, chronic active disease, and previous colonic resections were independently associated with the risk of developing MBD. Conclusions: The prevalence of MBD was significantly higher in CD patients. Besides the usual risk factors, we observed that factors related to chronic active and long‐lasting disease increased the risk of MBD. (Inflamm Bowel Dis 2010)

p53 Protein immunoexpression in esophageal squamous cell carcinoma and adjacent epithelium

Immunoreactivity for p53 tumor supressor gene product is commonly found in human malignancies and some premalignant lesions, but its role in cancer development and its value as a marker of tumor biologic behavior is still unclear.

CYR61 and TAZ Upregulation and Focal Epithelial to Mesenchymal Transition May Be Early Predictors of Barrett’s Esophagus Malignant Progression

Barrett’s esophagus is the major risk factor for esophageal adenocarcinoma. It has a low but non-neglectable risk, high surveillance costs and no reliable risk stratification markers. We sought to identify early biomarkers, predictive of Barrett’s malignant progression, using a meta-analysis approach on gene expression data. This in silico strategy was followed by experimental validation in a cohort of patients with extended follow up from the Instituto Português de Oncologia de Lisboa de Francisco Gentil EPE (Portugal). Bioinformatics and systems biology approaches singled out two candidate predictive markers for Barrett’s progression, CYR61 and TAZ. Although previously implicated in other malignancies and in epithelial-to-mesenchymal transition phenotypes, our experimental validation shows for the first time that CYR61 and TAZ have the potential to be predictive biomarkers for cancer progression. Experimental validation by reverse transcriptase quantitative PCR and immunohistochemistry confirmed the up-regulation of both genes in Barrett’s samples associated with high-grade dysplasia/adenocarcinoma. In our cohort CYR61 and TAZ up-regulation ranged from one to ten years prior to progression to adenocarcinoma in Barrett’s esophagus index samples. Finally, we found that CYR61 and TAZ over-expression is correlated with early focal signs of epithelial to mesenchymal transition. Our results highlight both CYR61 and TAZ genes as potential predictive biomarkers for stratification of the risk for development of adenocarcinoma and suggest a potential mechanistic route for Barrett’s esophagus neoplastic progression.

Low risk of adenocarcinoma and high-grade dysplasia in patients with non-dysplastic Barrett’s esophagus: Results from a cohort from a country with low esophageal adenocarcinoma incidence

Background The risk of esophageal adenocarcinoma (EAC) in non-dysplastic Barrett’s esophagus (NDBE) is considered to be approximately 0.3% per year or even lower, according to population-based studies. Data from countries with low EAC incidence are scarce. Our principal aim was to determine the incidence of high-grade dysplasia (HGD) and EAC in NDBE. Our secondary aims were to identify the predictors of progression and to calculate the incidence of HGD/EAC, by using the calculation method for surveillance time in population-based studies. Materials and methods A cohort of NDBE patients was prospectively followed up. Cases of HGD and EAC (study end points) diagnosed during the first year of follow-up were considered as prevalent. Only cases with an endoscopic surveillance time > 1 year were included in our analysis. Results We enrolled 331 patients (251 men) in the surveillance program. Their median age was 59 years (interquartile range (IQR): 47–67 years). Their median NDBE length was 3 cm (IQR: 2–4 cm). Of these patients, 80 died during the follow-up (one from EAC) and two were lost to follow-up. After 2284 patient-years of endoscopic follow-up (median surveillance time, 5 years (IQR: 2–10 years)), we found that five cases of HGD and two cases of EAC were diagnosed. The incidence of HGD/EAC was 3.1 cases per 1000 patient-years (95% CI: 1.3–6.0) and that of EAC was 0.9 (95% CI: 0.2–2.9). The incidence of HGD/EAC in short segments (≤ 3 cm) was 0.7 cases per 1000 patient-years (95% CI: 0.3–3.4). The sole variable that we found associated with progression was NDBE length. If the total surveillance time was considered (3537 patient-years), the incidence of HGD and EAC was only slight lower. Conclusions The incidence of HGD and EAC was very low in NDBE. Therefore, current surveillance guidelines must be reassessed, at least for short-segment BE.

Familial Adenomatous Polyposis and Crohn's Disease in One Patient: Dilemmas and Concerns

Familial adenomatous polyposis (FAP) and Crohns disease (CD) are two entities with no known etiologic or physiopathogenic relation. The rarity of the former makes the coincidence of both diagnoses in one patient very unlikely. Nevertheless, management in such cases can be puzzling as surgical options must be considered, and immunosuppression/immunomodulation is set in a territory of accelerated carcinogenesis. We report the case of a 29-year-old male with a diagnosis of FAP since adolescence, already submitted to prophylactic proctocolectomy, presenting with anemia and bloody diarrhea, revealing small bowel CD. This case allows for a rich discussion of the clinical dilemmas presenting when FAP and CD are diagnosed in the same patient and for a deep analysis of the concerns inherent to the available therapeutic options.

Efficacy of Long-Term Oral Vitamin B12 Supplementation after Total Gastrectomy: Results from a Prospective Study.

Background/Objectives: Vitamin B12 (VB12) deficiency is a common complication after total gastrectomy which may be associated with megaloblastic anemia and potentially irreversible neurologic symptoms. Intramuscular supplementation of VB12 has been considered the standard treatment, although it is associated with high costs and patient discomfort. Patients/Methods: We performed a prospective uncontrolled study (ACTRN12614000107628) in order to evaluate the clinical and laboratory efficacy of long-term oral VB12 supplementation in patients submitted to total gastrectomy. All patients received daily oral VB12 (1 mg/day) and were evaluated every 3 months (clinical and laboratory evaluation: hemoglobin, VB12, total iron, ferritin, and folate). Results: A total of 26 patients were included with a mean age of 64 years (29-79). Patients were included with a mean period of 65 months (3-309) after total gastrectomy. At inclusion time, 17/26 patients were under intramuscular VB12, and 9 had not started supplementation yet. There were normal serum VB12 levels in 25/26 patients (mean VB12 serum levels: 657 pg/mL). The mean follow-up period was 20 (8.5-28) months. During follow-up, all patients had normal VB12 levels and there was no need for intramuscular supplementation. The patient with low VB12 levels had an increase to adequate levels, which remained stable. There were no differences with statistical significance among VB12 levels at 6 (867 pg/mL), 12 (1,008 pg/mL), 18 (1,018 pg/mL), and 24 (1,061 pg/mL) months. Iron and folate supplementation was necessary in 21 and 7 patients, respectively. Conclusions: Oral VB12 supplementation is effective and safe in patients who underwent total gastrectomy and should be considered the preferential form of supplementation.

A case of multiple gastrointestinal stromal tumors caused by a germline KIT gene mutation (p.Leu576Pro)

Multiple gastrointestinal stromal tumors (GISTs) caused by germline KIT gene mutations are an extremely rare autosomal dominant disorder. We report a case of a 21-year-old woman who presented to the emergency department with a 2-week history of asthenia, palpitations and upper gastrointestinal bleeding. After further clinical evaluation one gastric and two small bowel GISTs were diagnosed, which were surgically resected after neoadjuvant therapy with Imatinib. Diffuse hyperplasia of the interstitial cells of Cajal was also seen in the background gastric and small intestinal walls. Somatic mutational analysis of the KIT gene revealed a substitution at codon 576 in exon 11 (p.Leu576Pro) in all tumors and normal ileal mucosa. The germline nature of this mutation was confirmed by mutation analysis in peripheral blood leukocytes. However, she had no familial history of GISTs and her parents did not carry the respective germline mutation.

Management of Severe Radiation Proctitis with Radiofrequency Ablation

We report the case of a 74-year-old female with a uterine carcinosarcoma with lung metastasis, who underwent pelvic radiotherapy (RT) followed by chemotherapy. Four months after RT, she presented with multiple episodes of rectal bleeding and anemia, requiring regular transfusions. Upper endoscopy was unremarkable and colonoscopy showed erythema, telangiectasias with coalescing patches, friability, and sparse ulcers, extending from the dentate line to the distal sigmoid colon, consistent with severe radiation proctitis (RP). The patient underwent two sessions of argon plasma coagulation (APC) therapy with clinical inefficacy, and required a total of 27 red blood cell transfusions and intravenous iron. Chemotherapy was suspended due to clinical deterioration. Six months after RT, she was admitted with profuse rectal bleeding, hypotension, and severe anemia (hemoglobin of 4.2 g/dL), requiring hemodynamic resuscitation. Colonoscopy revealed several telangiectasias, with multiple clots and oozing bleeding (Fig. 1). Considering the severity and extension of the disease and the limited efficacy of APC therapy, we performed radiofrequency ablation (RFA). Standard bowel preparation with 4 L of polyethylene glycol was done. After cleaning and aspiration of the blood content, the focal Halo90 catheter (Halo® system, Covidien GI Solutions, Sunnyvale, CA, USA) was placed at the 6 o’clock position onto the distal end of the gastroscope (GIF-190, Olympus). The catheter was pressed against the rectal mucosa and 2 energy pulses were applied per site (Fig. 2) (energy of 12 J/cm2, power density of 40 W/cm2). The ablated tissue was not removed after the first energy pulse to promote the hemostatic effect. The treatment was repeated from the proximal border of the radiation changes to the lower rectum. The distal rectum was ablated in retroflexion. Full circumference ablation was avoided to minimize the risk of stenosis [1]. Hemostasis was achieved at the end of the procedure and

Buried Barrett’s Esophagus with High-Grade Dysplasia after Radiofrequency Ablation

Radiofrequency ablation therapy is an effective endoscopic option for the eradication of Barrett’s esophagus that appears to reduce the risk of esophageal cancer. A concern associated with this technique is the development of subsquamous/buried intestinal metaplasia, whose clinical relevance and malignant potential have not yet been fully elucidated. Fewer than 20 cases of subsquamous neoplasia after the successful radiofrequency ablation of Barrett’s esophagus have been reported to date. Here, we describe a new case of subsquamous neoplasia (high-grade dysplasia) following radiofrequency ablation that was managed with endoscopic resection. Our experience suggests that a meticulous endoscopic inspection prior to and after radiofrequency ablation is fundamental to reduce the risk of buried neoplasia development.