hMLH1 promoter methylation and BRAF mutations in high-frequency microsatellite instability colorectal cancers not fulfilling the revised Bethesda guidelines.

PURPOSE: Sporadic colorectal cancers with high-frequency microsatellite instability (MSI-H) are related to hypermethylation of mismatch repair (MMR) genes and a higher frequency of BRAF mutations than Lynch syndrome. We estimated the feasibility of hereditary colorectal cancer based on hMLH1 methylation and BRAF mutations. METHODS: Between May 2005 and June 2011, we enrolled all 33 analyzed patients with MSI-H cancer (male:female, 23:10; mean age, 65.5 ± 9.4 years) from a prospectively maintained database that didn't match Bethesda guidelines and who had results of hMLH1 methylation and BRAF mutations. RESULTS: Among the 33 patients, hMLH1 promoter methylation was observed in 36.4% (n = 12), and was not significantly related with clinicopathologic variables, including MLH1 expression. BRAF mutations were observed in 33.3% of the patients (n = 11). Four of 11 and five of 22 patients with MSI-H colon cancers were BRAF mutation (+)/hMLH1 promoter methylation (-) or BRAF mutation (-)/hMLH1 promoter methylation (+). Of the 33 patients, 21.2% were BRAF mutation (+)/hMLH1 promoter methylation (+), indicating sporadic cancers. Seventeen patients (51.5%) were BRAF mutation (-)/hMLH1 promoter methylation (-), and suggested Lynch syndrome. CONCLUSION: Patients with MSI-H colorectal cancers not fulfilling the Bethesda guidelines possibly have hereditary colorectal cancers. Adding tests of hMLH1 promoter methylation and BRAF mutations can be useful to distinguish them from sporadic colorectal cancers.

An alternative pathway in colorectal carcinogenesis based on the mismatch repair system and p53 expression in Korean patients with sporadic colorectal cancer.

PURPOSE: Microsatellite instability (MSI) and chromosomal instability are main mechanisms underlying colorectal carcinogenesis. We determined the features and prognosis of colorectal cancer based on MSI including mismatch repair genes and expression of p53. METHODS: Between 1999 and 2008, a total of 2,649 colorectal cancer patients were analyzed using a prospective database. A mismatch repair defect (MMR-D) was defined as a loss of expression of more than one MMR protein and/or MSI-high. MMR-proficiency (MMR-P) was defined as expression of all MMR proteins and microsatellite stable (MSS)/MSI-low. Groups 1 (G1), 2 (G2), 3 (G3), and 4 (G4) were defined as MMR-D and p53-positive expression, MMR-D and p53-negative expression, MMR-P and p53-positive expression, MMR-P and p53-negative expression, respectively. RESULTS: Eighty-two (3.0%), 181 (6.8%), 1,368 (51.7%), and 1,018 (38.5%) patients were classified into groups 1-4, respectively. Comparison between G1 and G2 showed differences in location (p < 0.001), size (p = 0.030), node metastasis (p = 0.027), distant metastasis (p = 0.009), and stage (p = 0.040). Comparison between G3 and G4 showed differences in location (p < 0.001) and histology (p < 0.001). Comparison between G1 and G3 showed differences in location (p < 0.001) and histology (p < 0.001). Comparison between G2 and G4 showed differences in age (p < 0.001), location (p < 0.001), size (p = 0.006), histology (p < 0.001), node metastasis (p < 0.001), distant metastasis (p < 0.001), and stage (p < 0.001). On multivariate analysis, stage (p = 0.007) and histology (p < 0.001) were associated with improved overall survival, and stage (p < 0.001) was associated with disease-free survival. CONCLUSIONS: According to the MSI and p53 subsets, colorectal cancers showed different clinicopathologic features, but these subsets had no prognostic impact on overall and disease-free survival rate.

Transanal endoscopic microsurgery for the treatment of well-differentiated rectal neuroendocrine tumors.

PURPOSE: Recently, an increase in well-differentiated rectal neuroendocrine tumors (WRNETs) has been noted. We aimed to evaluate transanal endoscopic microsurgery (TEM) for the treatment of WRNETs. METHODS: Between December 1995 and August 2009, 109 patients with WRNETs underwent TEM. TEM was performed for patients with tumors sizes of up to 20 mm and without a lymphadenopathy. These patients had been referred from other clinics after having been diagnosed with WRNETs by using a colonoscopic biopsy; they had undergone a failed endoscopic submucosal dissection (ESD) or endoscopic mucosal resection (EMR) and exhibited an involved resection margin and remaining tumor after ESD or EMR, regardless of the distance from the anal verge. This study included 38 patients that had more than three years of follow-up. RESULTS: The mean age of the patients was 51.3 ± 11.9 years, the mean tumor size was 8.0 ± 3.9 mm, and no morbidity occurred. Thirty-five patients were asymptomatic. TEM was performed after a colonoscopic resection in 13 cases because of a positive resection margin, a residual tumor or a non-lifting lesion. Complete resections were performed in 37 patients; one patient with a positive margin was considered surgically complete. In one patient, liver metastasis and a recurrent mesorectal node occurred after five and 10 years, respectively. CONCLUSION: TEM might provide an accessible and effective treatment either as an initial or as an adjunct after a colonoscopic resection for a WRNET.

Early surgical outcomes of NiTi endoluminal compression anastomotic clip (NiTi CAC 30) use in patients with gastrointestinal malignancy.

BACKGROUND: The NiTi endoluminal Compression Anastomotic Clip (CAC™) 30 (NiTi CAC 30) (NiTi Alloys Technologies, Ltd., Netanya, Israel) is a new device with shape-memory characteristics. We aimed to investigate the safety and early surgical outcomes of NiTi CAC 30 for intestinal anastomosis in patients with gastrointestinal malignancy. SUBJECTS AND METHODS: Fifty patients operated on with NiTi CAC 30 were matched for sex, age, body mass index, operation type (open versus laparoscopy), operation name, and anastomosis type with patients in a control group operated on with a stapling device between November 2009 and May 2010. Early clinical outcomes were investigated. RESULTS: One misfired case of NiTi CAC 30 was excluded. Between the two groups, no significant differences were observed in demographics except for previous abdominal operation history. The results of early clinical outcomes were investigated, including operation time, estimated blood loss, time to first flatus, first defecation, and discharge, and complications. No differences were noted. Postoperatively, migration started in 1 patient between 3 and 5 days, 11 patients between 6 to 7 days, and 37 patients after 8 days. The expulsion of 31 cases occurred between 2 and 3 weeks, postoperatively. The NiTi CAC 30 was expulsed within 1 week in 4 patients and between 1 to 2 weeks in 8 patients. An expulsion occurred in 1 case at over 4 weeks. No problems related to early migration and expulsion were observed, and no anastomotic leakage and bleeding occurred. CONCLUSIONS: Intestinal anastomosis with the NiTi CAC 30 was safe and feasible without anastomotic leakage and reoperation compared with the stapling technique.

Treatment outcomes of anorectal melanoma.

PURPOSE: An anorectal melanoma (AM) is a very rare tumor. However, sufficient data supporting effective surgical options for the disease do not exist. This retrospective review aimed to analyze treatment outcomes for an AM. METHODS: From June 1999 to December 2008, we retrospectively reviewed a prospectively collected consecutive series of 19 patients who had undergone a surgical resection for an AM at a single institute. Surgical method and clinicopathological factors were analyzed. RESULTS: The median age was 61.4 years (range, 46 to79 years). Main symptoms were an anal mass, hematochezia, perianal pain, tenesmus, fecal incontinence, and bowel habit change. The average duration of symptoms before diagnosis was 7.8 months (range, 1 to 36 months). S-100 and HMB-45 were positive in all patients, even in non-melanin pigmentation. There were 12 abdominoperineal resections (APRs) and 7 wide local excisions (WEs). The APR showed longer overall survival when compared with the WE (64.1 months vs. 10.9 months, P < 0.001). No patients who underwent a WE survived more than 13 months. CONCLUSION: A high index of suspicion is necessary to establish the diagnosis for an AM in patients with anal symptoms, and S-100 and HMB-45 can be useful markers for an AM. Even with the small number of cases and the short follow-up, our data suggest that an APR for an AM may provide longer survival than a WE.

Oncologic outcome after cessation or dose reduction of capecitabine in patients with colon cancer.

PURPOSE: Oral capecitabine has been used as adjuvant therapy for colorectal cancer patients since the 1990s. Patient-initiated cessation or reduced use of capecitabine occurs widely for various reasons, yet the consequences of these actions are unclear. The present study sought to clarify treatment outcomes in such patients. METHODS: The study included 173 patients who had been diagnosed with stage II or III colon cancer according to the pathologic report after radical surgery at Samsung Medical Center from May 2005 to June 2007 and who had received capecitabine as adjuvant therapy. The patients were divided into groups according to whether the dose was reduced (I, dose maintenance; II, dose reduction) or stopped (A, cycle completion; B, cycle cessation). Recurrence and disease-free survival rates between the two groups each were analyzed. RESULTS: Of the 173 patients, 128 (74.6%) experienced complications, most frequently hand-foot syndrome (n = 114). Reduction (n = 35) or cessation (n = 18) of medication was most commonly due to complications. Concerning reduced dosage, both groups displayed no statistically significant differences in recurrence rate and 3-year disease-free survival rate. Concerning discontinued medication use, the cycle completion group showed an improved recurrence rate (P = 0.048) and 3-year disease-free survival rate (P = 0.028). CONCLUSION: The results demonstrate that maintaining compliance with capecitabine as an adjuvant treatment for colon cancer to preventing complications positively affects patient prognosis.

Elective laparoscopic repair after colonoscopic decompression for incarcerated morgagni hernia.

Plain radiographs of an 88-year-old woman who had experienced vomiting and abdominal distention for 3 days revealed a severely obstructed ileus, and abdominopelvic computed tomography revealed an incarcerated Morgagni hernia. The endoscope was passed through the constrictions from the diaphragmatic indentations and a thin catheter was placed for decompression. The obstructive ileus regressed markedly after the procedure; the patient underwent elective laparoscopic repair of the hernia 1 week later. This is believed to be the first case of endoscopic preoperative decompression for an incarcerated Morgagni hernia.

Characteristics of the killing mechanism of human natural killer cells against hepatocellular carcinoma cell lines HepG2 and Hep3B.

PURPOSE: Unlike normal hepatocytes, most hepatocellular carcinomas (HCCs) are quite resistant to death receptor-mediated apoptosis when the cell surface death receptor is cross linked with either agonistic antibodies or soluble death ligand proteins in vitro. The resistance might play an essential role in the escape from the host immune surveillance; however, it has not been directly demonstrated that HCCs are actually resistant to natural killer (NK) cell-mediated death. Therefore, this study investigated the molecular mechanism of NK cell-mediated cytotoxicity against the HCCs, HepG2, and Hep3B, using two distinct cytotoxic assays: a 4-h (51)Cr-release assay and a 2-h [(3)H] thymidine release assay which selectively measures the extent of necrotic and apoptotic target cell death, respectively. METHODS: Most of the target cells exhibited marked morphologic changes when they were co-incubated with the NK cells, and the NK cytotoxicity against these HCCs was comparable to that against K562, a NK-sensitive leukemia cell line, when the cytotoxicity was assessed by a 4-h (51)Cr release assay. RESULTS: The NK cells also induced significant apoptotic cell death in the Hep3B targets, but not in the HepG2 targets, when the cytotoxicity was assessed by a 2-h [(3)H]-thymidine release assay. In agreement with these results, procaspase-3 was activated in the Hep3B targets, but not in the HepG2 targets. Interestingly, mildly fixed NK cells had no detectable activity in the 4-h (51)Cr release assay against both HepG2 and Hep3B targets, while they were similarly effective as the untreated NK cells in the 2-h [(3)H]-thymidine release assay, suggesting that the level of apoptotic cell death of the Hep3B targets is granule independent and might be primarily mediated by the death ligands of the NK cells. CONCLUSION: This study found that a tumor necrosis factor (TNF)-related apoptosis-inducing ligand TRAIL)/TRAIL receptor interaction is involved in the NK cell-mediated apoptotic death of the Hep3B targets, but a Fas/Fas ligand (FasL) interaction is not.