MLH1 Deficiency Down-Regulates TLR4 Expression in Sporadic Colorectal Cancer.

Patients with mismatch repair (MMR)-deficient colorectal cancer (CRC) have a more favorable prognosis than patients with tumors with intact MMR. In order to obtain further insights on the reasons for this different outcome, we investigated the interplay between MMR genes and TLR4/MyD88 signaling. The cancer genome atlas (TCGA) databases were selected to predict the differential expression of TLR4 in colon cancer and its correlation with MMR genes. Moreover, the expression of MMR genes and TLR4 was evaluated by immunohistochemistry in 113 CRC samples and a cohort of 63 patients was used to assess TLR4 mRNA expression and MLH1 epigenetic silencing status. In vitro, the effect of MLH1 knockdown on TLR4 expression was quantified by Real Time PCR. TLR4 expression resulted dependent on MMR status and directly correlated to MLH1 expression. In vitro, MLH1 silencing decreased TLR4 expression. These observations may reflect the better prognosis and the chemoresistance of patients with CRC and MMR defects.

Colorectal cancer in the young: a possible role for immune surveillance?

BACKGROUND: Younger patients with colorectal cancer (CRC) generally have better survival in spite of worse clinical and pathological features. METHODS: Twenty-six patients under 50 years operated for primary CRC were enrolled and matched 1:2:2 according to stage, tumor site and gender with 52 patients from 50 to 70 years and 52 patients over 70 years old. RESULTS: Patients under 50 years had a significantly longer overall, cancer specific and disease free survival (p = .001, p = .007 and p = .05, respectively). However, they had more frequently lymphovascular invasion (p = .006) and they more frequently developed metachronous CRC at follow-up (p = .03). Nevertheless, preoperative lymphocytes blood count/white blood count (LBC/WBC) ratio inversely correlated with age at operation (rho = -.21, p = .04) and it predicted CRC recurrence with an accuracy of 70%, p < .001 (threshold value LBC/WBC = 0.21%) and better overall, cancer specific and disease free survival (p < .0001 for all). At multivariate analysis, stage and LBC/WBC ratio resulted independent predictors of disease free survival (p = .0001 and p = .01, respectively). CONCLUSIONS: Patients under 50 years had a significantly longer survival with a higher LBC/WBC ratio. These results could suggest a possible role of immunosurveillance in neoplastic control.

Synchronous polyps predict metachronous colorectal lesions after curative resection of colorectal cancer.

BACKGROUND: The principal aim of endoscopic follow-up programs after curative resection of colorectal cancer (CRC) is to improve survival and identify local recurrence and metachronous CRC. The aim of our study was to identify the possible predictors of metachronous colorectal lesions. METHODS: The records of 348 consecutive patients with CRC and who completed at least 1 year of endoscopic follow-up after surgery were analyzed. In this group, 336 patients underwent surgery for primitive CRC and 12 for metachronous cancer. Patients' characteristics, operative details, and endoscopical follow-up findings were retrieved. Multivariate survival analyses were used to identify patient categories at risk of metachronous colonic lesions. RESULTS: 128 patients presented a metachronous lesion: 118 adenomas and 10 adenocarcinomas. At multivariate analysis, active smoke (HR = 1.84, p = 0.03), neoadjuvant therapy (HR = 0.24, p = 0.01), and presence of synchronous polyps (HR = 1.55, p = 0.04) resulted independent predictors of metachronous adenoma after CRC removal while neoadjuvant therapy (HR = 0.25, p = 0.02), active smoke (HR = 1.54, p = 0.04), and presence of synchronous polyps (HR = 1.86, p = 0.02) resulted independent predictors of metachronous lesions after CRC removal. CONCLUSIONS: This study demonstrated a high rate of metachronous lesions in the early follow-up after curative CRC resection. The negative effects of synchronous polyps should be carefully evaluated when planning patients' follow-up.

Mismatch repair gene defects in sporadic colorectal cancer enhance immune surveillance.

BACKGROUND: There is evidence that colorectal cancers (CRC) with DNA mismatch repair deficiency (MMR-D) are associated with a better prognosis than the generality of large bowel malignancies. Since an active immune surveillance process has been demonstrated to influence CRC outcome, we investigated whether MMR-D can enhance the immune response in CRC. PATIENTS AND METHODS: A group of 113 consecutive patients operated for CRC (42 stage I or II and 71 with stage III or IV) was retrospectively analyzed. The expression of MMR genes (MSH2, MLH1, MSH6 and PSM2) and co-stimulatory molecule CD80 was assessed by tissue microarray immunohistochemistry. In addition, tumor infiltrating mononuclear cells (TIMC) and T cell subpopulations (CD4, CD8, T-bet and FoxP-3) were quantified. The effect of specific siRNA (siMSH2, siMLH1, siMSH6 and siPSM2) transfection in HT29 on CD80 expression was quantified by flow cytometry. Non parametric statistics and survival analysis were used. RESULTS: Patients with MMR-D showed a higher T-bet/CD4 ratio (p = 0.02), a higher rate of CD80 expression and CD8 lymphocyte infiltration compared to those with no MMR-D. Moreover, in the MMR-D group, the Treg marker FoxP-3 was not expressed (p = 0.05). MMR-D patients with stage I or II and T-bet expression had a significant better survival (p = 0.009). Silencing of MSH2, MLH1 and MSH6, but not PSM2, significantly increased the rate of CD80+ HT29 cells (p = 0.007, p = 0.023 and p = 0.015, respectively). CONCLUSIONS: CRC with MMR-D showed a higher CD80 expression, and CD8+ and Th1 T-cell infiltration. In vitro silencing of MSH2, MLH1 and MSH6 significantly increased CD80+ cell rate. These results suggest an enhanced immune surveillance mechanism in presence of MMR-D.

Obesity is a risk factor for multifocal disease and recurrence after colorectal cancer surgery: a case-control study.

BACKGROUND: Several studies have demonstrated that obesity is a risk factor for colorectal cancer (CRC), but few data are available regarding its role in multifocal disease and postoperative recurrence. The present study aimed to assess the role of obesity as a risk factor for multifocal disease and postoperative recurrence in patients with CRC. PATIENTS AND METHODS: The records of 940 consecutive patients with CRC admitted to three surgical centres between January 2006 and January 2011 were retrospectively analysed. The 595 individuals whose preoperative body mass index (BMI) values were available were included in the study. Following WHO guidelines, the patients were stratified into four groups depending on their BMI values. Age at disease onset, clinical presentation, tumor invasiveness, the presence of multiple foci, and the colon cancer recurrence rate in the four groups were assessed and compared. RESULTS: At multivariate analysis, diagnosis of familial adenomatous polyposis (FAP) and a BMI>30 were found to be independent predictors of synchronous polyps (Odd Ratio [OR]=10.7, 95% Confidence interval (CI)=2-75, p=0.005; and OR=2.2, 95% CI=1.3-3.9, p=0.003, respectively). The cancer recurrence rate in the patients with stage 2 CRC was significantly higher in the obese with respect to the non-obese (p=0.05). At multivariate analysis, BMI>30, FAP, and positivity by the Bethesda criteria were found to be independent predictors of recurrence after CRC surgery. CONCLUSION: Obese patients diagnosed with CRC require thorough colonic exploration prior to surgery and necessitate more frequent postoperative endoscopic examinations with respect to patients without any risk factors.

Acute appendicitis: what is the gold standard of treatment?

McBurney's procedure represented the gold-standard for acute appendicitis until 1981, but nowadays the number of laparoscopic appendectomies has progressively increased since it has been demonstrated to be a safe procedure, with excellent cosmetic results and it also allows a shorter hospitalization, a quicker and less painful postoperative recovery. The aim of this editorial was to perform a review of the literature in order to address controversial issues in the treatment of acute appendicitis.