Sundeep Singh Saluja

Association of epigenetic alteration in PTEN gene with colorectal cancer progression among Indian population

Dear Editor: Cancer is a complex genetic disease which gradually progresses in relation to the downregulated expression of tumor suppressor genes (TSGs). Inactivation of TSGs has been known to contribute to the abnormal proliferation, transformation, and progression in human cancers. It has been widely demonstrated that both the genetic and epigenetic events, together, play a crucial role in tumor progression. Epigenetic is defined as the heritable changes in gene expression that are not caused by alterations in the DNA sequence. Several studies have demonstrated the epigenetic alterations in colorectal carcinoma. Colorectal cancer (CRC) is the third most common malignancy worldwide and a leading cause of cancer death in women and men in the USA. In contrast, the frequency of colorectal carcinoma is less in India. However, 20,159 cases of CRC among men and 16,317 cases among women were reported in India. The 14,134 and 11,556 mortality due to CRC was reported among men and women, respectively, in India. Most of the CRC cases originate from adenomas. The malignant potential of adenomas increases with size, grade of dysplasia, and degree of villous components, along with the number and order of genetic and epigenetic aberrations. Previous studies have also highlighted the hypermethylation in several TSGs in colorectal carcinoma. Recent reports suggest that PTEN has an important tumor suppressor role in colorectal carcinogenesis. However, more attentive study is needed to explore the association of PTEN loss with CRC development. PTEN, a tumor suppressor gene, has been recently isolated from chromosome 10q23.3. The involvement of PTEN promoter methylation has been reported in breast cancer, cervical cancer, endometrial cancer, colorectal cancer, and glioblastoma. However, no such study has been made to evaluate the role of the PTEN tumor suppressor gene in colorectal cancer in colorectal cancer in Indian population. The correlation of the progression of disease with that of the promoter hypermethylation seems to be an interesting phenomenon. Therefore, we aimed to analyze the PTEN gene promoter methylation in fresh colorectal cancer tissues and their adjacent normal tissues along with the colorectal metastases specimens and also to evaluate the association of PTEN hypermethylation with CRC progression. The major outcome of the study is that the PTEN hypermethylation is a frequent event in sporadic CRCs and colorectal metastases in the patients from Indian population. Promoter methylation of PTEN gene was determined by methylationspecific PCR. We also performed chi-square test to correlate the PTEN hypermethylation with the clinicobiological parameters of colorectal cancer and metastases specimens in order to evaluate the role of PTEN hypermethylation with the disease progression. Of the CRC specimens, 114 (51 %) have shown PTEN hypermethylation among the total of 223 CRC specimens. Thirty-eight specimens have been characterized as metastatic among 223 specimens. Thirty-one (82 %) specimens out of 38 colorectal metastases samples have also demonstrated PTEN hypermethylation. We would like to highlight the high rate of hypermethylation in advanced stage colorectal tumors than early stages of colorectal tumors. To examine the M. M. A. Rizvi (*) :A. Ali : S. J. Mehdi Genome Biology Lab, Department of Biosciences, Jamia Millia Islamia, Maulana Mohammad Ali Jauhar Marg, New Delhi 110025, India e-mail: rizvijmi@gmail.com

High patency of proximal splenorenal shunt: A myth or reality ? – A prospective cohort study

BACKGROUND Proximal splenorenal shunt (PSRS) is a well-accepted surgical procedure for non-cirrhotic portal hypertension (NCPH). Though a patent shunt is important for good long term outcome, there are very few studies on patency of these shunts. We analysed shunt patency using dynamic computed tomographic (CT) portography and compared it with other modalities. METHODS From 2004 to 2014, 50 patients with PSRS were evaluated prospectively for shunt patency using dynamic CT portography, clinical parameters and ultrasound Doppler. RESULTS The causes of NCPH were extrahepatic portal vein obstruction (EHPVO) in 38 patients and non-cirrhotic portal fibrosis (NCPF) in 12 patients. The shunt patency rate using clinical parameters, ultrasound Doppler and dynamic CT portography were 70%, 40% and 60% respectively. Clinical parameters overestimated while ultrasound Doppler underestimated the shunt patency rate. Dynamic portography had 100% correlation with conventional angiography in the five patients when this was done. The site of shunt could be demonstrated convincingly by dynamic CT portography. The shunt patency rate decreased over time. It was 64%, 60% and 43% in <1 year, 1-5 years and >5 years respectively. Our NCPF patients had a greater shunt patency rate compared to EHPVO patients (9/12 vs. 21/38) though the difference was not significant. Only size of the splenic vein had a significant impact on the shunt patency rate on statistical analysis. CONCLUSIONS Dynamic CT portography is useful for evaluation of shunt patency. Proximal splenorenal shunts have a high blockage rate which has hitherto not been reported.

Intrarectal migration of mesh following Rectopexy: Case series and review of literature

INTRODUCTION Mesh rectopexy for complete rectal prolapse is associated with complications such as fecal impaction, constipation and rarely recurrence. Mesh erosion following rectopexy is rare. We report three such cases managed successfully in our unit. PRESENTATION OF CASES All three patients presented with constipation. In addition, one patient had sense of incomplete evacuation and another had protrusion of mesh through anal canal with recurrence of rectal prolapse. There was a delayed presentation in one patient at 15 years after initial surgery, while other two presented at 2 years and 5 years following rectopexy. Diagnosis was made by either per rectal examination or sigmoidoscopy. Two patients underwent trans abdominal removal of mesh along with anterior resection of rectum. In one patient, mesh was removed by transanal approach and sutured rectopexy was added to tackle the recurrent prolapse. All patients are symptom free on follow up with no recurrence of prolapse. DISCUSSION Mesh erosion following rectopexy has multifactorial aetiology with diverse presentation. It is important to recognise this significantly morbid complication as it amenable to surgical correction. Management depends up on the location of erosion, the severity of mesh protrusion into rectal lumen and the degree of fibrosis around the area of mesh. CONCLUSION The management of mesh erosion following rectopexy should be individualized. Although it is complex, acceptable functional outcome and quality of life can be achieved with proper treatment.

Is Intraoperative Confirmation of Malignancy During Pancreaticoduodenectomy Mandatory

Dear Editor, We read with great interest the article by Garcea et al. ‘Is Intraoperative Confirmation of Malignancy During PancreaticoduodenectomyMandatory?’ published in the issue 16 of the Journal of Gastrointestinal Surgery 2012. This article is about a very important dilemma faced by surgeons. We appreciate the authors for addressing this difficult problem. However, we have few queries regarding which we seek clarification from the authors. Authors have analysed their experience of 128 cases of which 62 had intraoperative frozen biopsy while 66 underwent Whipple’s pancreaticoduodenectomy with clinical suspicion of malignancy. It appears that there is some selection bias involved in categorizing these patients. Thirty-five percent (21/62) patients in the frozen biopsy group turned out to be benign compared to the 13.6 % (9/66) in no intraoperative histology group. We would like to know how these two categories were arrived at. Authors have also mentioned about crossover in their study. If that is the reason for the significant difference in the incidence of malignancy, then that would question the basis for the classification into two groups. A second problem is about obtaining the frozen biopsy. In cases of chronic pancreatitis with head mass, biopsy may be easily obtainable though it may still miss the malignant focus. In cases of lower end cholangiocarcinoma or small focus of malignancy nearby, a frozen biopsy is very difficult. Authors have not given their method of obtaining these frozen biopsies. Another aspect needs to be mentioned. Endoscopic ultrasound and guided FNAC as well as PET–CT may reduce the number of patients where this dilemma remains. 2 We would like to know from authors the number of patients these modalities were used including the results. We encounter two different subgroups of patients—one with the lower end cholangiocarcinoma where biopsy/ cytology has not been positive and the second group comprising patients having chronic pancreatitis with headmass.While frozen biopsy is possible in the latter category, it is mostly clinical guidance in the former. It seems that the two categories of patients presented by authors may be conforming broadly to this classification. Authors have left us with a mathematical projection and broadly concluded that any of the approaches would be equivalent. We believe that a frozen biopsy may be undertaken in patients of chronic pancreatitis with a head mass, while resection surgery should be undertaken for lower end CBD blocks if malignancy is suspected. Obtaining a positive biopsy is not mandatory, especially for centres which have low mortality and morbidity of Whipple’s pancreaticoduodenectomy. 4 On balance, a 30 % chance of cure in truly malignant cases weighs heavier against 3 % mortality in patients who ultimately turn out to be benign. Yours sincerely, Pramod Kumar Mishra, Sundeep Singh Saluja, Asit Arora and Raja Kalayarasan Department of Gastrointestinal Surgery, G B Pant Hospital and Maulana Azad Medical College

Decreased expression of MGMT in correlation with aberrant DNA methylation in esophageal cancer patients from North India

O-6-methylguanine-DNA methyltransferase, DNA repair gene, has been found to be involved with the pathogenesis of the esophageal cancer. DNA hypermethylation and other factors have been suggested to downregulate O-6-methylguanine-DNA methyltransferase. In this communication, the methylation status of O-6-methylguanine-DNA methyltransferase gene and the corresponding O-6-methylguanine-DNA methyltransferase protein expression in esophageal cancer from North India has been studied. In all, 80 samples of tumor tissue along with adjacent normal tissue as controls were analyzed for messenger RNA level of O-6-methylguanine-DNA methyltransferase gene, protein expression, and subcellular localization. The messenger RNA expression was studied using real-time quantitative polymerase chain reaction, protein expression, and its subcellular localization by Western blotting and immunohistochemistry. DNA methylation was assessed through methylation-specific polymerase chain reaction. Clinicopathological parameters were recorded and correlated with the O-6-methylguanine-DNA methyltransferase expression. O-6-methylguanine-DNA methyltransferase messenger RNA expression was found to be downregulated in 65% cases (52/80). The expression of O-6-methylguanine-DNA methyltransferase at the protein level was also found to be absent in 65% (52/80) cases. In all, 52 cases had low or no expression of the protein, whereas out of those 28 remaining cases, 11.25% (09/80) cases had high O-6-methylguanine-DNA methyltransferase protein expression. The absence of O-6-methylguanine-DNA methyltransferase protein coincided with the methylated cases in 84% (38/45), whereas in 07 cases, out of the 45 methylated, O-6-methylguanine-DNA methyltransferase protein was present. The aggressive esophageal cancer patients having methylated O-6-methylguanine-DNA methyltransferase had more than 50% cases with no/mild expression of the O-6-methylguanine-DNA methyltransferase protein (p > 0.001). Loss of O-6-methylguanine-DNA methyltransferase protein was very frequent in the incidence of esophageal cancer from North Indian patients, and methylation of the promoter region of O-6-methylguanine-DNA methyltransferase was significantly associated in its downregulation.

Allelic loss at PTEN locus leads to progression of colorectal carcinoma among North Indian patients

Abstract We evaluated the loss of heterozygosity (LOH) at 10q23.3 locus of microsatellite markers; D10S198, D10S192, and D10S541 of PTEN gene in 223 North Indian colorectal cancer (CRC) specimens. DNA was isolated and microsatellite-specific markers polymerase chain reaction was performed. Out of total 223 cases 102 showed LOH for at least one of the locus. In addition, thereto a significant association was found with the clinicopathologic features like grade of differentiation, clinical stage, invasion, lymph node invasion, and the clinical outcome (p < 0.05). These data argue that the given markers to check the possible LOH of PTEN gene at locus 10q23.3 could be considered as one of the diagnostic markers in CRC.

Stapled versus hand-sewn cervical esophagogastric anastomosis in patients undergoing esophagectomy: A Retrospective Cohort Study

Introduction Anastomotic leak is one of the main causes of morbidity following esophageal resection for carcinoma of the esophagus and gastroesophageal junction. We compared hand sewn and stapled cervical esophagogastric anastomotic techniques in terms of postoperative complications. Methods All patients who underwent esophagectomy with cervical esophagogastric anastomosis at a single academic center from 2004 to 2014 were included in the study. Both early and late complications were analyzed. Results 153 patients underwent resection for carcinoma of the esophagus and gastroesophageal junction. Of these 140 patients had esophagectomy with cervical esophagogastric anastomosis. 66 patients underwent a hand sewn anastomosis and 74 patients had a side-to-side stapled anastomosis fashioned. Both groups were comparable with respect to preoperative characteristics. There was no difference in the operative blood loss and T and N stage of the disease. The overall morbidity and mortality was 32.8% and 6.4%, respectively. Overall leak rate was 17%. There was no difference in the leak rates among two groups (12 in the hand-sewn group & 12 in the Stapled stapled group; p = 0.82). The rate of anastomotic stricture was significantly higher for the hand sewn group (16.1% vs 4.3%; p = 0.03) at median follow up of 30 months. Conclusion Both hand sewn and stapled anastomotic techniques are equally effective way of performing a cervical esophagogastric anastomosis. However, patients having anastomotic leak develop anastomotic stricture more often in those having hand-sewn anastomosis compared to stapled anastomosis.