Serum methylation levels of TAC1. SEPT9 and EYA4 as diagnostic markers for early colorectal cancers: a pilot study.

OBJECTIVE: To identify methylated genes in serum with diagnostic potentials for early colorectal cancer (CRC). METHODS: Serum methylation levels of up to 12 genes were measured in two sets of serum samples with the second set from 26 stage I CRC patients and 26 age/gender-matched controls. RESULTS: Serum methylation levels of TAC1, SEPT9, and EYA4 were significant discriminants between stage I CRC and healthy controls. Combination of TAC1 and SEPT9 rendered 73.1% sensitivity with 92.3% specificity. CONCLUSION: Serum methylation levels of TAC1. SEPT9 and EYA4 may be useful biomarkers for early detection of CRC though a validation study is necessary.

Endoscopic stenting and elective surgery versus emergency surgery for left-sided malignant colonic obstruction: a prospective randomized trial.

PURPOSE: This study aims to evaluate the role of colonic stenting as a bridge to surgery in acutely obstructed left-sided colon cancer. METHODS: Patients with acute left-sided malignant colonic obstruction with no evidence of peritonitis were recruited. After informed consent, patients were randomized to colonic stenting followed by elective surgery or immediate emergency surgery. Patients who had successful colonic stenting underwent elective surgery 1 to 2 weeks later, while the other group had emergency surgery. Patients in whom stenting was unsuccessful also underwent emergency surgery. RESULTS: Twenty patients were randomized to stenting and 19 to emergency surgery. Fourteen patients (70%) had successful stenting and underwent elective surgery at a median of 10 days later; the rest underwent emergency surgery. Technical stent failure occurred in five patients (25%). One patient failed to decompress after successful stent deployment. All patients underwent definitive colonic resection with primary anastomosis. Two of 20 patients in the stenting group required defunctioning stomas compared to 6 of 19 in emergency surgery group, p = 0.127. Overall complication rate was 35% versus 58% (p = 0.152) and mortality was 0% versus 16% (p = 0.106) in the stenting group and emergency surgery group, respectively. Postoperatively, the stenting group was discharged from hospital earlier (median of 6 versus 8 days, p = 0.028) than the emergency surgery group. CONCLUSION: Colonic stenting followed by interval elective surgery may be safer, with a trend towards lower morbidity and mortality when compared with the current practice of emergency surgery for left-sided malignant colonic obstruction.

Evaluation of laparoscopic versus open colorectal surgery in elderly patients more than 70 years old: an evaluation of 727 patients.

BACKGROUND: With longer life expectancy, surgeons can expect to operate on older patients. Laparoscopic colorectal (LC) surgery has been demonstrated to be superior to open surgery. Controversy persists, however, regarding benefits of LC in the elderly due to increase in operative time. The aim of our study was to compare short-term outcomes of LC versus open colorectal (OC) surgery in elderly patients. MATERIALS AND METHODS: Patients ≥70 years old that underwent elective LC between 2005 and 2008 were compared with controls who underwent OC. Data was extracted from a prospectively collected database. RESULTS: Seven hundred and twenty-seven patients underwent colorectal resection in this study period (LC n = 225, OC n = 502). The laparoscopic arm was characterised by shorter incisions (LC 6.0 cm vs. OC 12.0 cm, p < 0.001) but longer operating times (LC 125 min vs. OC 85 min, p < 0.001). Median use of narcotics and length of stay were significantly shorter in the laparoscopic group (LC 2 days vs. OC 3 days, p < 0.001 and LC 6 days vs. OC 7 days, p < 0.001, respectively). There was no significant difference in median recovery of bowel function (LC 4 days vs. OC 4 days, p = 0.14) and post-operative morbidity (p = 0.725). Thirty-day mortality was significantly lower in the laparoscopic arm (LC 1.3% vs. OC 4.6%, p = 0.03) CONCLUSION: This is the largest series from a single institution comparing LC and OC in elderly patients. In our series, LC in elderly patients was safe and not associated with a higher morbidity. LC was also associated with less narcotic use and shorter length of stay.

Metabolic profiling in colorectal cancer reveals signature metabolic shifts during tumorigenesis.

Colorectal cancer (CRC) arises as the consequence of progressive changes from normal epithelial cells through polyp to tumor, and thus is an useful model for studying metabolic shift. In the present study, we studied the metabolomic profiles using high analyte specific gas chromatography/mass spectrometry (GC/MS) and liquid chromatography tandem mass spectrometry (LC/MS/MS) to attain a systems-level view of the shift in metabolism in cells progressing along the path to CRC. Colonic tissues including tumor, polyps and adjacent matched normal mucosa from 26 patients with sporadic CRC from freshly isolated resections were used for this study. The metabolic profiles were obtained using GC/MS and LC/MS/MS. Our data suggest there was a distinct profile change of a wide range of metabolites from mucosa to tumor tissues. Various amino acids and lipids in the polyps and tumors were elevated, suggesting higher energy needs for increased cellular proliferation. In contrast, significant depletion of glucose and inositol in polyps revealed that glycolysis may be critical in early tumorigenesis. In addition, the accumulation of hypoxanthine and xanthine, and the decrease of uric acid concentration, suggest that the purine biosynthesis pathway could have been substituted by the salvage pathway in CRC. Further, there was a step-wise reduction of deoxycholic acid concentration from mucosa to tumors. It appears that to gain a growth advantage, cancer cells may adopt alternate metabolic pathways in tumorigenesis and this flexibility allows them to adapt and thrive in harsh environment.

Redefining conversion in laparoscopic colectomy and its influence on outcomes: analysis of 418 cases from a single institution.

BACKGROUND: The reported rates of conversion in laparoscopic colectomy are varied. The incidence of conversion is not, however, well defined. The aim of the present study is to redefine conversion and to analyze differences in outcome. METHODS: Treatment parameters of a total of 418 consecutive patients who underwent laparoscopic colonic resection from 2005 to 2007 were analyzed. Treatment was classified as laparoscopic colonic resection, laparoscopy-assisted colonic resection (lap-assisted), and laparoscopic conversion. RESULTS: There were significant differences in median operating time between laparoscopic colonic resection, lap-assisted, and laparoscopic conversion (125 min, 160 min, and 140 min; p = 0.0001); median hospital length of stay was significantly different (laparoscopic, 5.0 days, versus lap-assisted, 6.0 days, versus laparoscopic conversion, 6.5 days; p = 0.0001); and median incision length was also noted to vary significantly (laparoscopic, 5.0 cm, lap-assisted, 8.0 cm, and conversion, 12.0 cm; p = 0.00001). Multivariate analysis reveals that older age (Odds Ratio [OR] = 1.07, 95% Confidence Interval [CI] = 1.02-1.12), higher Body Mass Index ([BMI], OR = 1.15, 95% CI = 1.03-1.29), and pT stage were significant factors affecting conversion. Disease-free survival for cancers was not influenced by conversion (p = 0.653). The overall complication rate was 16.7% and was significantly increased in lap-assisted cases and in conversion cases (26% versus 13%; p = 0.003). CONCLUSIONS: A consistent definition for conversion in laparoscopic colonic resection is required. Our proposed definitions may provide a solution. The definition of lap-assisted as a separate entity serves as a bridge between laparoscopy and full conversion. Risk factors of age, BMI, and advanced tumor stage are conversion predictors and are associated with increased hospital stay and postoperative morbidity.

Evaluation of current devices in single-incision laparoscopic colorectal surgery: a preliminary experience in 32 consecutive cases.

BACKGROUND: Single-incision laparoscopic colorectal surgery (SILS) suggests a promising alternative to conventional laparoscopic surgery. In this report we describe our initial experience with SILS for both right hemicolectomies and anterior resections. METHODS: Between June 2009 and May 2010, SILS was performed for 32 consecutive cases with benign and malignant pathology. Demographic data, intraoperative parameters, postoperative data, and pathologic data were assessed. RESULTS: Twenty-one SILS right hemicolectomies, ten ARs, and one abdominal perineal resection (APR) were performed. For SILS right hemicolectomies, one case required full "conversion" to a laparoscopic procedure. The median operating time was 85 min (range 45-150 min) and the median wound length was 5.0 cm (range 3.0-10.0 cm). Median number of lymph nodes extracted in malignant cases was 17(range 10-30) and the overall median length of stay was 6 days (range 5-11). For left-sided lesions, ten cases of ARs (7 high ARs, 2 low ARs, 1 ultralow AR) and one APR were performed. Three cases were completed successfully via the SILS procedure, four cases required one additional port, and four cases required full "conversion" to a laparoscopic procedure. The median operating time was 120 min (range 65-235 min) and the median wound length was 5.0 cm (range 3.0-7.0 cm). Overall median length of stay was also 6 days (range 5-21). There was one case of anastomotic leak and one case of postoperative bleeding. CONCLUSION: In our experience, SILS for right hemicolectomies is safe and effective with reproducible oncologic results. SILS AR, however, requires greater modifications in current devices and techniques. SILS AR can be performed for both malignant and benign diseases but additional ports may be necessary for the safe completion of the procedure.

Krukenberg tumors of colorectal origin: a dismal outcome--experience of a tertiary center.

BACKGROUND: Krukenberg tumor (KT) is described as metastases of the ovary usually from a tumor of gastric origin. As colorectal cancer (CRC) is now the most common cancer in Singapore, we are seeing more KT with colorectal origin. PURPOSE: To determine the pattern of presentation of KT from CRC origin in terms of patient demographics, time of onset related to the diagnosis of CRC, presence of elevated serum tumor markers, carcinomatosis peritoneii, and survival of patients. METHODS: A retrospective database review of all patients diagnosed with KT from CRC treated in a specialized colorectal surgery department between August 1992 and March 2004. RESULTS: Twenty-five patients' records were available for analysis. Median age at diagnosis was 53 years old (range: 38-79). Sixteen patients (64%) had ovarian metastasis at the time of diagnosis of the CRC. Eleven patients (44%) had unilateral ovarian involvement. Nineteen patients (76%) had carcinomatosis peritoneii. Serum Carcinoembryonic antigen (CEA) was available for 21 patients, 18 (86%) were raised; serum cancer antigen-125 (CA-125) was available for seven patients, five (71%) were raised. There were 11 mortalities (44%) and all died of the disease. Median time between diagnosis of KT and death was 19 months. The rest of the patients were alive with existence of disease at last follow-up. CONCLUSION: KT is associated with a dismal outcome and poor prognosis. There was 0% disease-free survival. Serum CEA and CA-125 tend to rise in patients with KT. Patients investigated for elevated CA-125 and unilateral ovarian mass should have the diagnosis of colorectal cancer excluded before treatment of ovarian mass.

Prospective randomised study to evaluate the use of DERMABOND ProPen (2-octylcyanoacrylate) in the closure of abdominal wounds versus closure with skin staples in patients undergoing elective colectomy.

BACKGROUND: Topical 2-octylcyanoacrylate tissue (OCA) adhesive has been used as an alternative to close wounds with a comparable cosmetic outcome. The use of 2-OCA in the closure of abdominal laparotomy wounds has not been thoroughly evaluated. Our aim was to compare 2-OCA with conventional skin stapling devices in colorectal surgery. METHODS: A prospective randomised study was conducted in which 74 consecutive patients above the age of 21 undergoing open elective colectomies for benign or malignant indications were allocated to skin closure with 2-OCA or skin staples. Cosmetic outcome as assessed with the Hollander Cosmesis Scale with a single assessor, complication rates, and patient satisfaction were recorded at discharge (4-10POD) 2 weeks after discharge and then at 3 months. RESULTS: Of the 74 patients, 38 were randomised to skin staples and 36 to 2-OCA. There was no significant difference in cosmetic outcomes between the two groups as assessed with a visual analogue scale or the Hollander Cosmesis Scale but showed a trend to better cosmetic outcomes in the 2-OCA group. Patient satisfaction scores were higher but did not reach statistical significance. The time taken to close a wound with 2-OCA was significantly longer than with skin staples. There was no statistical difference in rates of wound infection. CONCLUSION: 2-OCA is a safe and effective means of skin closure in patients undergoing elective colectomies with a good and at least equivalent outcome to traditional methods of closure.

Stapled anastomosis for anterior resection is safe even after previous stapled haemorrhoidectomy--a report of five cases.

INTRODUCTION: Stapled haemorrhoidectomy has become popular for the treatment of symptomatic bleeding or prolapsing piles. There are concerns about the safety of another stapled low colorectal anastomosis after rectal resection if a patient who has had previous stapled haemorrhoidectomy subsequently develops colorectal neoplasia requiring an anterior resection. METHODS: A retrospective review of patients who underwent stapled haemorrhoidectomy and subsequently had anterior resection from 1999 to 2008 was performed. RESULTS: Five patients (all male) were found to have distal sigmoid or rectal tumours on surveillance colonoscopy after stapled haemorrhoidectomy. Median age was 65 years (range 58-71). All underwent anterior resection with stapled end-to-end colorectal anastomosis at median of 29 months (range 18-60 months) after the initial stapled haemorrhoidectomy. Median anastomotic height was 12 cm (range 1-12 cm). A defunctioning ileostomy was created for three out of five patients. All the colorectal anastomoses healed uneventfully. CONCLUSIONS: Stapled colorectal anastomosis may be safely performed after previous stapled haemorrhoidectomy.

Critical analysis of mucin and signet ring cell as prognostic factors in an Asian population of 2,764 sporadic colorectal cancers.

INTRODUCTION: Conflicting data on the clinicopathological characteristics as well as prognosis and survival of signet ring cell (SRC) and mucinous adenocarcinomas (MA) of the colorectum persist. METHODS: Consecutive patients (2,764) with sporadic colorectal cancer from 1999 to 2005 were evaluated. The clinicopathological characteristics of these patients were reviewed. Univariate analysis was performed, and survival curves were constructed using the Kaplan-Meier method. Multivariate analysis assessed independent prognostic factors. RESULTS: The incidence of MA and SRC is 6% and 1.1%, respectively. MA and SRC tend to occur in patients aged

Single site laparoscopic right hemicolectomy: an oncological feasible option.

INTRODUCTION: We present the first 7 cases of single site right hemicolectomy in Asia using the new Single Site Laparoscopy (SSL) access system from Ethicon Endo-surgery. METHODS: Right hemicolectomy was performed using the new Single Site Laparoscopy (SSL) access system. Patient demographics, operative time, histology and post operative recovery and complications were collected and analysed. RESULTS: The median operative time was 90 mins (range 60 - 150 mins) and a median wound size of 2.5 cm (range 2 to 4.5 cm). The median number of lymph nodes harvested was 24 (range 20 to 34 lymph nodes). The median length of proximal margin was 70 mm (range 30 to 145 mm) and that of distal margin was 50 mm (35 to 120 mm). All patients had a median hospital stay of 7 days (range 5 to 11) and there were no significant perioperative complications except for 1 patient who had a minor myocardial event. CONCLUSION: Right hemicolectomy using SSL access system is feasible and safe for oncologic surgery.

Germline bone morphogenesis protein receptor 1A mutation causes colorectal tumorigenesis in hereditary mixed polyposis syndrome.

OBJECTIVES: Hereditary mixed polyposis syndrome (HMPS) is characterized by polyps of mixed adenomatous/hyperplastic/atypical juvenile histology that are autosomal dominantly inherited and that eventually lead to colorectal cancer (CRC). Although CRC with adenomatous polyps is initiated by inactivating adenomatous polyposis coli (APC), the initiating event of CRC with mixed polyps remains unclear. We aimed to identify the underlying germline defect in HMPS. METHODS: We screened for bone morphogenesis protein receptor 1A (BMPR1A) mutation by exonic sequencing, reverse-transcriptase polymerase chain reaction (PCR) followed by cDNA sequencing, and multiplex ligation-dependent probe amplification (MLPA) analysis in eight Singapore Chinese HMPS families. RESULTS: Germline BMPR1A defects were found in four (50%) families. In two families, it is shown to co-segregate with the disease phenotype in all affected members over three generations, indicating that it is the disease-causing mutation. CRC incidence is 75%. The most defining characteristic is the presence of mixed hyperplastic-adenomatous polyps. Juvenile polyps are rarely reported, and if present, are usually of mixed components. Detailed histology of the polyps from one patient over 11 years distinguishes HMPS from juvenile polyposis syndrome (JPS). We report further the first cases of Wilms' tumor and papillary thyroid carcinoma associated with BMPR1A germline defect. CONCLUSIONS: Germline BMPR1A defect is the disease-causing mutation in 50% of the HMPS families. If patients present with mixed morphology polyps in the large bowel that are autosomal dominantly inherited and corresponding absence of upper gastrointestinal abnormalities, the gene to begin mutation screening should be BMPR1A rather than APC.

Improved survival in an Asian cohort of young colorectal cancer patients: an analysis of 523 patients from a single institution.

BACKGROUND: Colorectal cancer (CRC) in the young is rare. Outcomes remain varied compared to older populations. The study reviews characteristics and overall survival (OS) of CRC in patients < or =50 years old. MATERIALS AND METHODS: Five hundred and twenty-three (14%) of 3,796 sporadic CRCs were identified. Patients were compared for demographics, tumour characteristics, treatment, and 5-year overall specific survival. Independent prognostic factors were evaluated. RESULTS: The majority were males (54%) with a median age of 45 years (range 19-50 years). Sixty-three percent of the patients presented with advanced stage disease (stage III and IV), and tumours were predominantly left-sided (83%). A higher frequency of mucinous or signet ring cell histological subtypes (16% vs 9%, p = 0.028) as well as poorly differentiated tumours (30% vs 12%, p = 0.0001) were present in younger patients < or =40 years. With a median follow-up of 41 months, the 5-year OS is 58% (95% confidence interval 53-64%). Younger patients < or =40 years had significantly superior 5-year OS of 62% vs 58% in the age group 41-50 years old (p = 0.004). Multivariate analysis identified five independent prognostic features: age group of 41-50 years, poorly differentiated tumour grade, presence of perineural infiltration, high tumour stage, and carcinoembryonic antigen values > or =5 ng/ml. CONCLUSION: This study has revealed significantly improved 5-year survival in young CRC compared to those reported in the literature.

Laparoscopic versus open right hemicolectomy: a comparison of short-term outcomes.

BACKGROUND: The laparoscopic approach is increasingly becoming the gold standard for colorectal resections. While laparoscopic surgery of the left colon and rectum has been evaluated in many studies, laparoscopic resection of the right colon has not been as widely examined. The aim of this study was to examine the short-term outcomes after laparoscopic right hemicolectomies and to determine if they were superior when compared with those after open resection. PATIENTS AND METHODS: Consecutive cases of laparoscopic right hemicolectomies performed between May 2005 and December 2007, in the Department of Colorectal Surgery, Singapore General Hospital, were compared with a matched series of patients who underwent open surgery. RESULTS: From a total of 37 laparoscopic cases, 36 patients successfully underwent laparoscopic right hemicolectomies. There was one conversion, giving a conversion rate of 2.7%. These 37 patients were compared with 40 patients who underwent open right hemicolectomies. The laparoscopic arm was characterised by shorter length of incisions (5.7 vs. 11.2 cm, p < 0.001) but longer operating times (110.8 vs. 71.6 min, p < 0.001). Mean number of lymph nodes harvested and length of proximal and distal margins were similar in both groups. There were also no significant differences between the groups in terms of narcotic use, recovery of bowel function, length of stay, post-operative morbidity and 30-day mortality. CONCLUSION: Laparoscopic right hemicolectomies are as feasible and safe as the open technique. They confer improved cosmesis with smaller incisions but at the expense of longer operating time.

Screening for colorectal cancer using a quantitative immunochemical faecal occult blood test: a feasibility study in an Asian population.

BACKGROUND: The quantitative immunochemical faecal occult blood test (qFOBT) has been shown to be an accurate method of identifying significant colorectal neoplasia including cancer and advanced adenomas. This study reports the results of a Singapore population-based colorectal cancer screening event using the qFOBT. METHODS: This event was held as part of a colorectal cancer awareness exhibition. All asymptomatic individuals above the age of 40 years with no previous colorectal cancer screening in the last 1 year were invited to participate. Eligible participants were screened using two consecutive qFOBTs with a positive faecal haemoglobin threshold taken at 100 ng/mL. Participants with at least one positive qFOBT result were recalled and advised to undergo colonoscopy. Endoscopic polypectomy or surgery was performed according to colonoscopic findings. RESULTS: A total of 751 (55% male, 45% female) participants with a median age of 53 years (range, 40-85 years) took part in the screening event. Five hundred and forty (72%) participants returned the qFOBT samples, of which 57 (11%) tested positive. Fifty-two of these participants proceeded to colonoscopy. Three participants had sigmoid cancer and 12 had advanced polyps, all of which were located distally in the sigmoid colon or rectum. Five of the participants required surgery for colorectal neoplasia and all recovered well without complications. CONCLUSION: The qFOBT at a positive faecal haemoglobin threshold of 100 ng/ml has a high positive predictive value and is an effective screening tool for colorectal cancer in an Asian population.

Short-term results of DST EEA 33 stapler and neu@ anoscope for stapled haemorrhoidectomy: a prospective study of 1,118 patients from a single centre.

BACKGROUND: Stapled haemorrhoidectomy has been performed with different techniques and staplers. We review our initial experience with the new DST EEA 33 stapler and neu@ anoscope. METHODS: A review of all patients who underwent stapled haemorrhoidectomy using the DST EEA 33 over a 14-month period was conducted. Short-term outcomes of bleeding, pain and retention of urine requiring admission or strictures requiring surgical intervention were studied. RESULTS: There were 1,118 patients operated from August 2007 to October 2008. The median age was 46-year-old (20-82 years) and 51% were females. The median operating time was 15 min (range 5-45 min), and median follow-up was 7 months (range 3-16 months). There were 26 patients (2.3%) who were admitted for inability to pass urine and 20 required catheterisation. Fifty-two patients (4.6%) were admitted for post-operative bleeding. In 32 cases the bleeding stopped spontaneously, while 19 patients required adrenaline injection and packing for hemostasis. Only one patient required surgical hemostasis. Thirty-three patients (2.9%) were admitted for post-operative pain and stayed for a median of 1 day (range 1-4 days). There were 14 patients (1.2%) who developed anorectal strictures requiring surgical intervention. All underwent anoplasty at a median of 3 months post-operatively (range 2-5 months), with good result. There were no recurrent haemorrhoids during follow-up. CONCLUSION: Stapled haemorrhoidectomy using the DST EEA 33 stapler is safe. The neu@ anoscope provides good visibility and handling, and is a useful tool in this procedure.

Histone H3 (lys-9) deacetylation is associated with transcriptional silencing of E-cadherin in colorectal cancer cell lines.

Epigenetic parameters linked to E-cadherin gene were investigated in 5 human colorectal cancer cell lines. Treatment with trichostatin A led to enhanced acetylation of histone H3-K9 with concurrent induction of E-cadherin mRNA in 3 E-cadherin low/negative cell lines that are not DNA methylated. Co-treatment with 5-aza-2'-deoxycytidine and trichostatin A resulted in additive/synergic induction of E-cadherin mRNA in all 5 cell lines with concomitant enhancement of histone H3-K9 acetylation in 4 E-cadherin low/negative cell lines. Our results suggest that histone H3-K9 deacetylation appears to play a crucial role in transcriptional repression of E-cadherin in colorectal cancers.

Intraabdominal schwannomas: a single institution experience.

INTRODUCTION: Intraabdominal schwannomas are rare, benign tumors. This study presents a single institution experience with 12 such tumors. METHODS: Between 1991 to 2006, 12 patients with a pathologically proven intraabdominal schwannoma were identified from a series of 216 mesenchymal tumors and were reviewed retrospectively. RESULTS: There were nine females and three male patients with a median age of 58 years (range 35-88 years). Eleven patients were symptomatic, and the tumors were located in the stomach (n = 8), jejunum, colon, rectum, and lesser sac. Multiple preoperative investigations including endoscopies with biopsies and computed tomography (CT) scans were performed, but none yielded a correct definitive preoperative diagnosis. The median tumor size was 52 mm (range 18-95 mm). Pathological examination demonstrated the 11 gastrointestinal tract (GIT) schwannomas to be solid homogenous tumors, which were highly cellular and were composed of spindle cells with positive staining for S100 protein. The pathological appearance of the lesser sac schwannoma was distinct as it demonstrated cystic degeneration with hemorrhage and Antoni A and B areas on microscopy typical of soft tissue schwannomas. All 12 patients were disease-free at a median follow-up of 22 months (range 1-120 months). CONCLUSION: Intraabdominal schwannomas are rare tumors, which are most frequently located within the GIT. GIT schwannomas are difficult if not impossible to diagnose preoperatively as endoscopic and radiologic findings are nonspecific. The treatment of choice is complete surgical excision because of diagnostic uncertainty, and the long-term outcome is excellent as these lesions are uniformly benign.

Detection of BRAF V600E mutation by pyrosequencing.

INTRODUCTION: Detection of the V600E hotspot mutation in BRAF oncogene is extremely useful for the screening of hereditary non-polyposis colorectal cancer (Lynch's syndrome) and for the prediction of sensitivity to MEK inhibitors. Here we describe a method for detecting this mutation based upon pyrosequencing technology. METHODS: The efficiency of pyrosequencing for detecting BRAF V600E mutations was compared with the conventional dideoxy sequencing method in 12 tumour cell lines and in 108 colorectal tumours. RESULTS: The results from pyrosequencing were 100% concordant with those from dideoxy sequencing. This method was capable of detecting BRAF V600E mutations at a much lower ratio of mutant to wild-type alleles (1:50) than dideoxy sequencing (1:5) while being considerably faster and less expensive. CONCLUSIONS: Pyrosequencing offers a specific, sensitive, rapid and cost-effective alternative to dideoxy sequencing for the detection of BRAF V600E mutations in clinical tumour specimens.

A susceptibility gene set for early onset colorectal cancer that integrates diverse signaling pathways: implication for tumorigenesis.

PURPOSE: The causative genes for autosomal dominantly inherited familial adenomatous polyposis (FAP) and hereditary nonpolyposis colorectal cancer have been well characterized. There is, however, another 10% to 15% of early onset colorectal cancers (CRC) in which the genetic components are unclear. In this study, we used microarray technology to systematically search for differentially expressed genes in early onset CRC. EXPERIMENTAL DESIGN: Young patients with non-FAP or non-hereditary nonpolyposis colorectal cancer, and healthy controls were age- (