Differential mucin phenotypes and their significance in a variation of colorectal carcinoma

AIM: To investigate mucin expression profiles in colorectal carcinoma (CRC) histological subtypes with regard to clinicopathologic variables and prognosis. METHODS: Mucin (MUC)2 and MUC5AC expressions were assessed by immunohistochemistry for a total of 250 CRC cases that underwent surgical resection. CRCs included 63 well-to-moderately differentiated adenocar-cinomas (WMDAs), 91 poorly differentiated adenocarcinomas (PDAs), 81 mucinous adenocarcinoma (MUAs), and 15 signet-ring cell carcinomas (SRCCs). MUC2 and MUC5AC were scored as positive when ≥ 25% and ≥ 1% of cancer cells were stained positive, respectively. The human mutL homolog 1 and human mutS homolog 2 expressions were assessed by immunohistochemistry in PDAs to investigate mismatch-repair (MMR) status.Tumors that did not express either of these two were considered MMR-deficient. Results were analyzed for associations with clinicopathologic variables and the prognosis in individual histological CRC subtypes. RESULTS: MUC2-positive and MUC5AC-positive WMDA percentages were 49.2% and 30.2%, respectively. In contrast, MUC2-positive and MUC5AC-positive PDA percentages were 9.5% and 51.6%, respectively. MUC2 levels tended to decrease and MUC5AC levels tended to increase from WMDA to PDA. In 21 tumors comprising both adenoma and adenocarcinoma components in a single tumor (4 WMDAs, 7 PDAs, and 10 MUAs), MUC2 was significantly downregulated in PDA and MUC5AC was downregulated in PDA and MUA in the adenoma-carcinoma sequence. These results suggested that MUC2 levels might be associated with malignant potential and that MUC5AC expression was an early event in tumorigenesis. Despite worse prognoses than WMDA, high MUC2 expression levels were maintained in MUA (95.1%) and SRCC (71.5%), which suggested a pathogenesis for these subtypes distinct from that of WMDA. No significant associations were found between MUC2 expression and any clinicopathologic variables in any histological subtype. MUC5AC expression in PDA was closely associated with right-sided location (P = 0.017), absence of nodal metastasis (P = 0.010), low tumor node metastasis stage (P = 0.010), and MMR deficiency (P = 0.003). MUC2 expression in WMDA was a marginal prognostic factor for recurrence/metastasis-free survival (RFS) by univariate Cox analysis (P = 0.077) but not by multivariate Cox analysis (P = 0.161). MUC5AC expression in PDA was a significant prognostic factor for RFS by univariate Cox analysis (P = 0.007) but not by multivariate Cox analysis (P = 0.104). Kaplan-Meier curves and log-rank tests revealed that MUC2 expression was marginally associated with a better WMDA prognosis [P = 0.064 for RFS and P = 0.172 for overall survival (OS)] but not for PDA. In contrast, MUC5AC expression was significantly and marginally associated with a better PDA prognosis in terms of RFS and OS, respectively(P = 0.004 for RFS and P = 0.100 for OS), but not for WMDA and MUA. CONCLUSION: Mucin core protein expression profiles and clinical significance differ according to histological CRC subtypes. This may reflect different pathogeneses for these tumors.

Molecular pathogenesis of sporadiccolorectal cancers

Colorectal cancer(CRC)results from the progressive accumulation of genetic and epigenetic alterations that lead to the transformation of normal colonic mucosa to adenocarcinoma.Approximately 75%of CRCs are sporadic and occur in people without genetic predisposition or family history of CRC.During the past two decades,sporadic CRCs were classified into three major groups according to frequently altered/mutated genes.These genes have been identified by linkage analyses of cancer-prone families and by individual mutation analyses of candidate genes selected on the basis of functional data.In the first half of this review,we describe the genetic pathways of sporadic CRCs and their clinicopathologic features.Recently,large-scale genome analyses have detected many infrequently mutated genes as well as a small number of frequently mutated genes.These infrequently mutated genes are likely described in a limited number of pathways.Gene-oriented models of CRC progression are being replaced by pathway-oriented models.In the second half of this review,we summarize the present knowledge of this research field and discuss its prospects.

Feasibility of single-incision laparoscopic cholecystectomy for acute cholecystitis

AIM: To assess the safety of single-incision laparoscopic cholecystectomy(SILC) for acute cholecystitis.METHODS: All patients who underwent SILC at Sano Hospital(Kobe, Japan) between January 2010 and December 2014 were included in this retrospective study. Clinical data related to patient characteristics and surgical outcomes were collected from medical records. The parameters for assessing the safety of the procedure included operative time, volume of blood loss, achievement of the critical view of safety, use of additional trocars, conversion to laparotomy, intraoperative and postoperative complications, and duration of postoperative hospital stay. Patient backgrounds were statistically compared between those with and without conversion to laparotomy.RESULTS: A total of 100 patients underwent SILC for acute cholecystitis during the period. Preoperative endoscopic treatment was performed for suspected choledocholithiasis in 41 patients(41%). The mean time from onset of acute cholecystitis was 7.7 d. According to the Updated Tokyo Guidelines(TG13) for the severity of cholecystitis, 86 and 14 patients had grade Ⅰ and grade Ⅱ acute cholecystitis, respectively. The mean operative time was 87.4 min. The mean estimated blood loss was 80.6 mL. The critical view of safety was obtained in 89 patients(89%). Conversion laparotomy was performed in 12 patients(12%). Postoperative complications of Clavien-Dindo grade Ⅲ or greater were observed in 4 patients(4%). The mean duration of postoperative hospital stay was 5.7 d. Patients converted from SILC to laparotomy tended to have higher days after onset.CONCLUSION: SILC is feasible for acute cholecystitis; in addition, early surgical intervention may reduce the risk of laparotomy conversion.

Intraoperative frozen section diagnosis of bile duct margin for extrahepatic cholangiocarcinoma

AIM To evaluate the usefulness of frozen section diagnosis(FSD) of bile duct margins during surgery for extrahepatic cholangiocarcinoma(CCA). METHODS We retrospectively analyzed 74 consecutive patients who underwent surgery for extrahepatic CCA from 2012 to 2017, during which FSD of bile duct margins was performed. They consisted of 40 distant and 34 perihilar CCAs(45 and 55 bile duct margins, respectively). The diagnosis was classified into three categories: negative, borderline(biliary intraepithelial neoplasia-1 and 2, and indefinite for neoplasia), or positive. FSD in the epithelial layer, subepithelial layer, and total layer was compared with corresponding permanent section diagnosis(PSD) postoperatively.Then, association between FSD and local recurrence was analyzed with special reference to borderline.RESULTS Analysis of 100 duct margins revealed that concordance rate between FSD and PSD was 68.0% in the total layer, 69.0% in the epithelial layer, and 98.0% in the subepithelial layer. The extent of remaining biliary epithelium was comparable between FSD and PSD, and more than half of the margins lost > 50% of the entire epithelium, suggesting low quality of the samples. In FSD, the rate of negative margins decreased and that of borderline and positive margins increased according to the extent of the remaining epithelium. Diagnostic discordance between FSD and PSD was observed in 31 epithelial layers and two subepithelial layers. Alteration from borderline to negative was the most frequent(20 of the 31 epithelial layers). Patients with positive margin in the total and epithelial layers by FSD demonstrated a significantly worse local recurrence-free survival(RFS) compared with patients with borderline and negative margins, which revealed comparable local RFS. Patients with borderline and negative margins in the epithelial layer by PSD also revealed comparable local RFS. These results suggested that epithelial borderline might be regarded substantially as negative. When classifying the status of the epithelial layer either as negative or positive, concordance rates between FSD and PSD in the total, epithelial, and subepithelial layers were 95.0%, 93.0%, and 98.0%, respectively.CONCLUSION During intraoperative assessment of bile duct margin, borderline in the epithelial layer can be substantially regarded as negative, under which condition FSD is comparable to PSD.

Clinical importance of colonoscopy in patients with gastric neoplasm undergoing endoscopic submucosal dissection

AIM To evaluate the usefulness of total colonoscopy(TCS) for patients undergoing gastric endoscopic submucosal dissection(ESD) and to assess risk factors for colorectal neoplasms.METHODS Of the 263 patients who underwent ESD at our department between May 2010 and December 2013, 172 patients undergoing TCS during a one-year period before and after ESD were targeted. After excluding patients with a history of surgery or endoscopic therapy for colorectal neoplasms, 158 patients were analyzed. Of the 868 asymptomatic patients who underwent TCS during the same period because of positive fecal immunochemical test(FIT) results, 158 patients with no history of either surgery or endoscopic therapy for colorectal neoplasms who were matched for age and sex served as the control group for comparison.RESULTS TCS revealed adenoma less than 10 mm in 53 patients(33.6%), advanced adenoma in 17(10.8%), early colorectal cancer in 5(3.2%), and advanced colorectalcancer in 4(2.5%). When the presence or absence of adenoma less than 10 mm, advanced adenoma, and colorectal cancer and the number of adenomas were compared between patients undergoing ESD and FITpositive patients, there were no statistically significant differences in any of the parameters assessed. The patients undergoing ESD appeared to have the same risk of colorectal neoplasms as the FIT-positive patients. Colorectal neoplasms were clearly more common in men than in women(P = 0.031). Advanced adenoma and cancer were significantly more frequent in patients with at least two of the following conditions: hypertension, dyslipidemia, and diabetes mellitus(P = 0.019).CONCLUSION In patients undergoing gastric ESD, TCS appears to be important for detecting synchronous double neoplasms. Advanced adenoma and cancer were more common in patients with at least two of the following conditions: hypertension, dyslipidemia, and diabetes mellitus. Caution is therefore especially warranted in patients with these risk factors.

Quantitative Microbiological Evaluation of <i>Salmonella</i>Typhimurium Shed in Diarrhea, Loose, and Normal Stools of Infected Pigs

Control of within-herd transmission of Salmonella is important for reducing the prevalence of this organism on pig farms and for preventing Salmonella-contamination of pork. At the farm level, understanding the within-herd transmission of Salmonella can lead to more effective control. Salmonella infection is dependent on the inoculation dose;hence, quantitative evaluation of Salmonella shed in feces would provide useful information for developing effective measures. In this study, to reproduce and evaluate the number of Salmonella shed in diarrhea, loose stools, and normal feces, weaned pigs were inoculated with 3.2 × 109, 3.2 × 107, and 3.2 × 105 cfu of Salmonella Typhimurium, respectively. The number of S. Typhimurium shed in the feces peaked within 1 week post-inoculation in every group and the most amount of diarrhea and loose stools were observed within 2 weeks post-inoculation. Diarrhea occurred 10 times (six pigs), and loose stools were observed 25 times (11 pigs). The average concentration of S. Typhimurium shed in diarrhea, loose stools, and normal feces was 1.0 × 108, 1.6 × 104, and 7.1 × 101 cfu/g feces, respectively. These data suggest that diarrhea and loose stools are significant sources of within-herd transmission of Salmonella. Moreover, as some of the normal feces contained >1.0 × 106 cfu/g of S. Typhimurium, even normal feces could be a source of within-herd transmission of Salmonella. At Salmonella-positive farms, reduction of the amount of Salmonella shed even in normal feces would lead to better control of within-herd transmission of Salmonella. These data can contribute to the control of within-herd transmission of Salmonella, particularly during the weaning period.

Differential Expression of Glu-Tubulin in Basal-Like Phenotype Carcinoma of the Mammary Gland

High levels of tubulin expression have been described in a variety of human malignant tumors, and glu-tubulin, in which the C-terminal tyrosine of α-tubulin is removed by tubulin carboxypeptidase. Over-expression has been reported in the malignant tumors of the mammary gland and correlated with poor prognosis immunohistochemically. Furthermore, Nielsen et al. proposed that the use of a panel of four markers (ER, HER 2, CK 5/6, and EGFR) could accurately identify basal-like phenotype carcinoma (BPC) with widely available standard pathologic tools. In our study, major prognostic factors such as patient age, tumor size, histological grade, axillary lymph node metastasis, vessel invasion, and local recurrence in BPC were not significantly different from non BP carcinoma (NBPC). However, the BPC group showed a higher ratio of distant metastasis than that of the NBPC group. In triple-negative carcinoma (TNC) cases, staining for glu-tubulin was observed in 46 cases (63.8%), which consisted of 42 of the 58 BPC patients (72.4%) and 4 of the 14 NBPC patients (28.6%). A significant association was found between the expression of glu-tubulin and BPC, but not NBPC. It seems that our findings also agree with the observation that BPC exhibits aggressive biological behavior and increases the content of glu-tubulin, which plays a greater role in migration and invasion.