Intracellular domain of epithelial cell adhesion molecule induces Wnt receptor transcription to promote colorectal cancer progression.

BACKGROUND: Epithelial cell adhesion molecule (EpCAM) has been widely studied as a tumor antigen due to its expression in varieties of solid tumors. Moreover, the glycoprotein contributes to critical cancer-associated cellular functionalities via its extracellular (EpEX) and intracellular (EpICD) domains. In colorectal cancer (CRC), EpCAM has been implicated in the Wnt signaling pathway, as EpICD and ß-Catenin are coordinately translocated to the nucleus. Once in the nucleus, EpICD transcriptionally regulates EpCAM target genes that; however, remains unclear whether Wnt signaling is modulated by EpICD activity. METHODS: Patient-derived organoids (PDOs), patient-derived xenografts (PDXs), and various CRC cell lines were used to study the roles of EpCAM and EpICD in Wnt receptor expression. Fluorescence and confocal microscopy were used to analyze tumors isolated from PDX and other xenograft models as well as CRC cell lines. EpCAM signaling was intervened with our humanized form of EpCAM neutralizing antibody, hEpAb2-6. Wnt receptor promoters under luciferase reporters were constructed to examine the effects of EpICD. Luciferase reporter assays were performed to evaluate promoter, γ-secretase and Wnt activity. Functional assays including in vivo tumor formation, organoid formation, spheroid and colony formation experiments were performed to study Wnt related phenomena. The therapeutic potential of EpCAM suppression by hEpAb2-6 was evaluated in xenograft and orthotopic models of human CRC. RESULTS: EpICD interacted with the promoters of Wnt receptors (FZD6 and LRP5/6) thus upregulated their transcriptional activity inducing Wnt signaling. Furthermore, activation of Wnt-pathway-associated kinases in the ß-Catenin destruction complex (GSK3ß and CK1) induced γ-secretase activity to augment EpICD shedding, establishing a positive-feedback loop. Our hEpAb2-6 antibody blocked EpICD-mediated upregulation of Wnt receptor expressions and conferred therapeutic benefits in both PDX and orthotopic models of human CRC. CONCLUSIONS: This study uncovers relevant functions of EpCAM where Wnt receptors are upregulated via the transcriptional co-factor activity of EpICD. The resultant enhancement of Wnt signaling induces γ-secretase activity further stimulating EpICD cleavage and its nuclear translocation. Our humanized anti-EpCAM antibody hEpAb2-6 blocks these mechanisms and may thereby provide therapeutic benefit in CRC.

The Negative Prognostic Impact of Lymph Node Skip Metastasis in Stage III Colon Cancer With pN1 Disease: A Single-Center and Retrospective Cohort Study.

BACKGROUND: Lymph node skip metastasis is a subgroup of lymph node metastatic patterns with low incidence in node-positive colon cancer. Its clinical significance is still unclear. OBJECTIVE: This study aimed to investigate the prognostic impact of lymph node skip metastasis in stage III colon cancer. DESIGN: This is a retrospective observational analysis. SETTINGS: The study was conducted at the Taipei Veterans General Hospital. PATIENTS: This study included patients with stage III colon cancer who underwent D3 lymphadenectomy between 2006 and 2015. MAIN OUTCOME MEASURES: The patients were divided into a lymph node skip metastasis-positive group and a negative group. Recurrence-free survival and overall survival were compared using Kaplan-Meier curves and log-rank test. Cox regression was applied to identify related risk factors influencing survival. RESULTS: A total of 461 patients were reviewed, and lymph node skip metastasis-positive patients represented 13.2% of our sample. Patients with lymph node skip metastasis tended to present with a higher proportion of right-sided cancer, lower positive lymph nodes, lower lymph node ratio, and higher mean BMI. Liver recurrence was more prevalent in the lymph node skip metastasis group ( p = 0.028) than in the negative group. The presence of lymph node skip metastasis was a negative prognostic factor for 5-year recurrence-free survival (51.4% vs 68.7%; p = 0.002) and 5-year overall survival (66.4% vs 80.4%; p = 0.024) in Kaplan-Meier curves and multivariate Cox regression. Subgroup analysis revealed the survival significance of recurrence-free survival ( p = 0.001) and overall survival ( p = 0.011) in lymph node skip metastasis with pN1 disease. LIMITATIONS: This study was limited by its retrospective design, single-center nature, and sampling error. CONCLUSIONS: Lymph node skip metastasis is an independent negative prognostic factor in stage III colon cancer with pN1 disease. More intensive surveillance may be necessary for patients of this subgroup. See Video Abstract at https://links.lww.com/DCR/C60 . IMPACTO PRONSTICO NEGATIVO DE LAS METSTASIS DISCONTNUAS GANGLIONARES LINFTICAS EN CASOS DE CNCER DE COLON ESTADIO III CON ENFERMEDAD PN ESTUDIO DE COHORTES RETROSPECTIVO MONOCENTRICO: ANTECEDENTES:Las metástasis discontínuas ganglionares linfáticas, son un subgrupo de patrones metastásicos en los ganglios linfáticos con baja incidencia en el cáncer de colon con nódulos positivos. Su significado clínico aún no está claro.OBJETIVO:Estudio que tiene por objetivo el investigar el impacto pronóstico de las metástasis discontínuas de los ganglios linfáticos en el cáncer de colon de estadio III.DISEÑO:Análisis observacional retrospectivo.AJUSTES:El estudio se realizó en el Hospital General de Veteranos de Taipei.PACIENTES:Pacientes con cáncer de colon en estadio III que se sometieron a linfadenectomía D3 entre 2006 y 2015.PRINCIPALES MEDIDAS DE RESULTADO:Los pacientes se dividieron en un grupo positivo de metástasis discontínuas en los ganglios linfáticos y un otro grupo negativo. La sobrevida libre de recidiva y la sobrevida global, fueron comparadas mediante las curvas de Kaplan-Meier y la prueba de rango logarítmico. Se aplicó la regresión de Cox para identificar los factores de riesgo relacionados que influyeron en la sobrevida.RESULTADOS:Se revisaron un total de 461 casos, donde los pacientes positivos con metástasis en los ganglios linfáticos representaron el 13,2% de nuestra muestra. Los pacientes con metástasis discontínuas ganglionares linfáticas tendían a presentar una mayor proporción de cáncer localizado en el lado derecho del colon, presentar un menor numéro de ganglios linfáticos positivos y una proporción menor de ganglios linfáticos con un IMC promedio más alto. Las recidivas hepáticas fueron más prevalentes en el grupo de metástasis discontínuas ganglionares linfáticas ( p = 0,028) que en el grupo negativo. La presencia de metástasis discontínuas ganglionares linfáticas fué un factor de pronóstico negativo en la sobrevida libre de recidiva a 5 años (51,4% frente a 68,7%, p = 0,002) y la sobrevida general a 5 años (66,4% frente a 80,4%, p = 0,024) evaluada por las curvas de Kaplan-Meier y la regresión multivariada de Cox. El análisis de subgrupos reveló la importancia de la sobrevida libre de recidiva ( p = 0,001) y la sobrevida general ( p = 0,011) en los casos con metástasis discontínuas ganglionares linfáticas con enfermedad pN1.LIMITACIONES:Diseño retrospectivo, naturaleza de centro único y error de muestreo.CONCLUSIONES:Las metástasis discontínuas ganglionares linfáticas son un factor pronóstico negativo independiente en los casos de cáncer de colon estadio III con enfermedad pN1. Tal vez sea necesaria una mayor vigilancia de los pacientes en este subgrupo.Consulte Video Resumen en https://links.lww.com/DCR/C60 . (Traducción-Dr. Xavier Delgadillo ).

Clinical outcome of local treatment and radical resection for pT1 rectal cancer.

BACKGROUND: Rectal cancer is mainly cured by radical resection with neoadjuvant chemoradiation or adjuvant chemotherapy. Pathological T1 lesions can be managed by local treatment and radiotherapy thereafter. Lower morbidity is the key benefit of these local treatments. Since nodal metastasis is important for staging, radical resection (RR) is suggested. Rectal cancer has higher surgical morbidity than colon cancer; local treatment has been the preferred choice by patients. METHODS: We retrospectively enrolled data of 244 patients with pT1 rectal adenocarcinoma. A total of 202 patients (82.8%) underwent RR, including low anterior resection (LAR) and abdomino-perineal resection (APR), and 42 patients (17.2%) underwent LT, including transanal excision and colonoscopic polypectomy. RESULTS: In our study, seven patients (16.7%) had loco-regional recurrence and distant metastasis from the LT group while eight patients (4.0%) had distant metastasis without loco-regional recurrence from the RR group. The lymph node metastasis rate in RR group was 8.4%. Forty-seven patients (24.2%) underwent LAR with temporary stoma, and its reversal rate was 100%. In the RR group, postoperative complication rate was 10.4% with a mortality rate of 0.5%. Recurrence-free survival (RFS) was 95.7% for RR and 80.2% for LT (P = 0.001), and overall survival (OS) was 93.7% for RR and 70.0% for LT (P = 0.001). CONCLUSION: This study found that RFS and OS in patients of pT1 rectal adenocarcinoma that had received RR were better than receiving LT. Further adjuvant chemotherapy was possible for some RR patients. A higher recurrence rate after LT must be balanced against the morbidity and mortality associated with RR.

Three-dimensional versus conventional two-dimensional laparoscopic colectomy for colon cancer: A 3-year follow-up study.

Background: Three-dimensional (3D) laparoscopy was developed to overcome the drawbacks of two-dimensional (2D) laparoscopy, namely lack of depth perception. However, the benefit of 3D laparoscopy in colorectal surgery is inconclusive. Here, we compare the 3-year follow-up outcomes of 3D and 2D laparoscopic colectomy. Patients and Methods: A total of 91 consecutive patients who underwent either 3D or 2D laparoscopy colectomy from October 2015 to November 2017 by a single surgical team for colon cancer were enrolled. Data were collected from a prospectively constructed database, including clinico-pathological features and operative parameters. The pathological results, recurrence, survival and systemic treatment were collected from the Taiwan Cancer Database. Results: There were 47 patients in the 3D group and 44 in the 2D group. There were no significant differences in characteristics of patients, operation data, pathological results, complications, operative time, blood loss or the number of lymph node harvested between the two groups. In addition, disease-free survival and overall survival were equal between the two groups. Conclusions: This is the first long-term result of a 3D laparoscopic colectomy. In our 3-year follow-up, there was no difference in long-term outcomes between 2D and 3D laparoscopy for colorectal surgery in an experienced centre.

The efficacy of anti-EGFR therapy in treating metastatic colorectal cancer differs between the middle/low rectum and the left-sided colon.

BACKGROUND: Clinically, metastatic rectal cancer has been considered a subset of left-sided colon cancer. However, heterogeneity has been proposed to exist between high and middle/low rectal cancers. We aimed to examine the efficacy of anti-epidermal growth factor receptor (EGFR) treatment for middle/low rectal and left-sided colon cancers. METHODS: This study enrolled 609 patients with metastatic colorectal cancer who were treated with anti-EGFR therapy. They were divided into groups based on primary tumour locations: the right-sided colon, the left-sided colon or the middle/low rectum. The efficacy of first-line and non-first-line anti-EGFR treatment was analysed. Genomic differences in colorectal cancer data from The Cancer Genome Atlas (TCGA) were investigated and visualised with OncoPrint and a clustered heatmap. RESULTS: On first-line anti-EGFR treatment, patients with middle/low rectal tumours had significantly lower progression-free survival, overall survival, and overall response rates (6.8 months, 27.8 months and 43%, respectively) than those with left-sided colon cancer (10.1 months, 38.3 months and 66%, respectively). Similar outcomes were also identified on non-first-line anti-EGFR treatment. In TCGA analysis, rectal tumours displayed genetic heterogeneity and shared features with both left- and right-sided colon cancer. CONCLUSIONS: Anti-EGFR treatment has lower efficacy in metastatic middle/low rectal cancer than in left-sided colon cancer.

Insulin-Like Growth Factor 2 mRNA-Binding Protein 1 (IGF2BP1) Is a Prognostic Biomarker and Associated with Chemotherapy Responsiveness in Colorectal Cancer.

Insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) is an RNA-binding protein and serves as a post-transcriptional fine-tuner regulating the expression of mRNA targets. However, the clinicopathological roles of IGF2BP1 in colorectal cancer (CRC) remains limited. Thus, we aimed to elucidate the clinical significance and biomarker potentials of IGF2BP1 in CRC. A total of 266 specimens from two sets of CRC patients were collected. IGF2BP1 expression was studied by immunohistochemical (IHC) staining. The Kaplan-Meier survival plot and a log-rank test were used for survival analysis. The Cox proportional hazards model was applied to determine the survival impact of IGF2BP1. Public datasets sets from The Cancer Genome Atlas (TCGA) and Human Cancer Metastasis Database (HCMDB), receiver operating characteristic (ROC) plotter, and two CRC cell lines, HCT-116 and DLD-1, were used for validating our findings. We showed that IGF2BP1 was overexpressed in tumor specimens compared to 13 paired normal parts by examining the immunoreactivity of IGF2BP1 (p = 0.045). The increased expression of IGF2BP1 in primary tumor parts was observed regardless of metastatic status (p < 0.001) in HCMDB analysis. IGF2BP1 expression was significantly associated with young age (59.6% vs. 46.7%, p-value = 0.043) and advanced stage (61.3% vs. 40.0%, p-value = 0.001). After controlling for confounding factors, IGF2BP1 remained an independent prognostic factor (HR = 1.705, p-value = 0.005). TCGA datasets analysis indicated that high IGF2BP1 expression showed a lower 5-year survival rate (58% vs. 65%) in CRC patients. The increased expression of IGF2BP1 in chemotherapy non-responder rectal cancer patients was observed using a ROC plotter. Overexpression of IGF2BP1 promoted the colony-forming capacity and 5-fluorouracil and etoposide resistance in CRC cells. Here, IGF2BP1 was an independent poor prognostic marker in CRC patients and contributed to aggressive phenotypes in CRC cell lines.

RAB27B-activated secretion of stem-like tumor exosomes delivers the biomarker microRNA-146a-5p, which promotes tumorigenesis and associates with an immunosuppressive tumor microenvironment in colorectal cancer.

The dynamic cell-cell communication is essential for tissue homeostasis in normal physiological circumstances and contributes to a diversified tumor microenvironment. Although exosomes are extracellular vesicles that actively participate in cell-cell interaction by shutting cellular components, impacts of tumor exosomes in the context of cancer stemness remain elusive. Here, we expand colorectal cancer stem cells (CRCSCs) as cancer spheroids and demonstrate that the ß-catenin/Tcf-4-activated RAB27B expression is required for the secretion of CRCSC exosomes. In an exosomal RNA sequencing analysis, a switch of exosomal RNA species from retrotransposons to microRNAs (miRNAs) is identified upon expanding CRCSCs. miRNA-146a-5p (miR-146a) is the major miRNA in CRCSC exosomes and exosomal miR-146a promotes stem-like properties and tumorigenicity by targeting Numb in recipient CRC cells. Among 53 CRC patients, those with abundant exosomal miR-146a expression in serum exhibits higher miR-146aHigh /NumbLow CRCSC traits, an increased number of tumor-filtrating CD66(+) neutrophils and a decreased number of tumor-infiltrating CD8(+) T cells. Our study elucidates a unique mechanism of tumor exosome-mediated stemness expansion.

Combined Microsatellite Instability and Elevated Microsatellite Alterations at Selected Tetranucleotide Repeats (EMAST) Might Be a More Promising Immune Biomarker in Colorectal Cancer.

BACKGROUND: The form of microsatellite instability (MSI) affecting tetranucleotide repeats known as elevated microsatellite alterations at selected tetranucleotide repeats (EMAST) has emerged as a new potential biomarker in multiple cancers. In colorectal cancer (CRC), the correlation between EMAST and MSI mutations remain inconclusive. MATERIALS AND METHODS: We evaluated 1,505 patients with CRC using five EMAST markers (D20S82, D20S85, D8S321, D9S242, and MYCL1) and the Bethesda panel of MSI markers. Most commonly, mutations involved in CRCs were identified by MassArray Assay, and DNA repair genes were analyzed by next-generation sequencing. Clinical characteristics and prognostic relevance were correlated with EMAST and MSI. RESULTS: Tumors that were EMAST positive and MSI high (MSI-H) were detected in 159 (10.6%) and 154 (10.2%) of 1,505 patients with CRC. Patients were divided into four groups according to EMAST and MSI status (EMAST-positive and MSI-H, EMAST-positive and microsatellite-stable [MSS], EMAST-negative and MSI-H, and EMAST-negative and MSS). The EMAST-positive and MSI-H group was associated with female predominance, higher prevalence of proximal colon tumors, early stage tumors, poorly differentiated tumors, mucinous histology, and higher incidence of mutations in PI3KCA, BRAF, TGFBR, PTEN, and AKT1 compared with other groups. Furthermore, compared with only EMAST-positive tumors or only MSI-H tumors, tumors that were both EMAST-positive and MSI-H had a higher frequency of MLH1, MSH3, MSH6, PMS2, and EXO1 gene mutations. Finally, the presence of EMAST-positive and MSI-H tumors was a good prognostic indicator in CRC. CONCLUSION: High mutations in several DNA repair genes in EMAST-positive and MSI-H tumors suggest that this subtype of CRC might be more suitable for treatment with immune therapy. IMPLICATIONS FOR PRACTICE: Elevated microsatellite alterations at selected tetranucleotide repeats (EMAST) is a unique molecular subtype of colorectal cancer (CRC). The current study demonstrated that the EMAST-positive and MSI-high (MSI-H) group was associated with female predominance, higher prevalence of proximal colon tumors, early stage tumors, poorly differentiated tumors, mucinous histology, and higher incidence of mutations in PI3KCA, BRAF, TGFBR, PTEN, and AKT1 compared with other groups. Most importantly, high mutations in DNA repair genes and MSI-related genes in EMAST-positive and MSI-H tumors suggest that this subtype of CRC might be more suitable for treatment with immune therapy compared with MSI-H tumors alone.

Prognosticators of Long-Term Outcomes of TNM Stage II Colorectal Cancer: Molecular Patterns or Clinicopathological Features.

BACKGROUND: Patients with stage II colorectal cancer (CRC) have a higher risk of recurrence when they have certain risk factors, including clinical and pathological patterns. However, as the prognostic role of molecular patterns for stage II disease is still unclear, this study aimed to investigate it. METHODS: A total of 509 patients with stage II CRC were enrolled, and all clinical, pathological, and molecular data were collected. Molecular patterns included microsatellite instability (MSI); elevated microsatellite alterations at selected tetranucleotides (EMAST) status; and expression of RAS/RAF genes, genes of the APC pathway, and other gene mutations. The endpoints were oncological outcomes, including overall survival (OS), cancer-specific survival (CSS), disease-free survival (DFS), local recurrence (LR), and distant recurrence (DR). Cox regression analysis was used. RESULTS: Numerous molecular patterns influenced the oncological outcomes on univariate analysis, but no variable reached significance in LR. On multivariate analysis, a mucinous component (MC) > 50% (P < 0.01) was significant for OS and CSS. Lymphovascular invasion (LVI; P< 0.01), MC > 50% (P < 0.01), and EMAST-H (P = 0.02) significantly influenced DFS, whereas LVI (P < 0.01), MC > 50% (P < 0.01), and TP53 mutation (P = 0.02) were significant for DR. CONCLUSIONS: In this study, MSI, EMAST, and RAS/RAF alterations did not influence the oncological outcomes. Overall, LVI and MC were two significant prognostic factors for DFS and DR. Thus, the histopathology, rather than the genes, plays a major role in the prognosis of patients with stage II CRC.

Risk factors for delayed perineal wound healing and its impact on prolonged hospital stay after abdominoperineal resection.

BACKGROUND: Perineal wound complications are a long-lasting issue for abdominoperineal resection (APR) patients. Complication rates as high as 60% have been reported, with the most common complication being delayed perineal wound healing. The aim of this study was to identify risk factors for delayed perineal wound healing and its impact on prolonged hospital stay. METHODS: We included low rectal tumor patients who underwent APR at a referral medical center from April 2002 to December 2017; a total of 229 patients were included. The basic characteristics and surgical outcomes of the patients were analyzed to identify risk factors for delayed perineal wound healing (> 30 days after APR) and prolonged hospital stay (post-APR hospital stay > 14 days). RESULTS: All patients received primary closure for their perineal wound. The majority of patients were diagnosed with adenocarcinoma (N = 213, 93.1%). In the univariate analysis, patients with hypoalbuminemia (albumin < 3.5 g/dL) had an increased risk of delayed wound healing (39.5% vs. 60.5%, P = 0.001), which was an independent risk factor in the multivariable analysis (OR 2.962, 95% CI 1.437-6.102, P = 0.003). Patients with delayed wound healing also had a significantly increased risk of prolonged hospital stay (OR 6.404, 95% CI 3.508-11.694, P < 0.001). CONCLUSIONS: Hypoalbuminemia was an independent risk factor for delayed wound healing, which consequently led to a prolonged hospital stay. Further clinical trials are needed to reduce the incidence of delayed perineal wound healing by correcting albumin levels or nutritional status before APR.

Clinical significance of the BRAFV600E mutation in Asian patients with colorectal cancer.

BACKGROUND: To investigate the clinicopathological features and prognostic significance of the BRAFV600E mutation in Asian patients with colorectal cancer. METHODS: We retrospectively reviewed the medical records of 1969 patients with colorectal cancer admitted to Taipei Veterans General Hospital for surgical treatment between 2000 and 2013. The measured endpoint was overall survival after surgery. The prognostic value of the BRAFV600E mutation was analyzed using the log-rank test and Cox regression analysis. RESULTS: The BRAFV600E mutation was detected in 106 (5.4%) patients and associated with female gender, abnormal cancer antigen (CA)19-9 at diagnosis, microsatellite status, right-sided primary tumors, mucinous histology, poor differentiation, and lymphovascular invasion. Metastatic patterns were more common in non-regional lymph node metastasis (20.8 vs. 7.4%, p = 0.06) and peritoneal seeding (41. vs. 21.2%, p = 0.04). Mutations were not prognostic in the overall survival of the entire study group but only in specific patients: age < 65, normal carcinoembryonic antigen at diagnosis, and stage IV disease. CONCLUSION: The BRAFV600E mutation was associated with distinct clinicopathological features and metastatic patterns. The overall survival rate was lower in selected colorectal patients with the BRAFV600E mutation.

Differences in gene mutations according to gender among patients with colorectal cancer.

BACKGROUND: The incidence, site distribution, and mortality rates of patients with colorectal cancer differ according to gender. We investigated gene mutations in colorectal patients and wanted to examine gender-specific differences. METHODS: A total of 1505 patients who underwent surgical intervention for colorectal cancer were recruited from March 2000 to January 2010 at Taipei Veterans' General Hospital and investigated for gene mutations in K-ras, N-ras, H-ras, BRAF, loss of 18q, APC, p53, SMAD4, TGF-ß, PIK3CA, PTEN, FBXW7, AKT1, and MSI. RESULTS: There were significant differences between male and female patients in terms of tumor location (p < 0.0001) and pathological stage (p = 0.011). The female patients had significantly more gene mutations in BRAF (6.4 vs. 3.3%, OR 1.985, p = 0.006), TGF-ß (4.7 vs. 2.5%, OR 1.887, p = 0.027), and revealed a MSI-high status (14.0 vs. 8.3%, OR 1.800, p = 0.001) than male patients. Male patients had significantly more gene mutations in N-ras (5.1 vs. 2.3%, OR 2.227, p = 0.012); however, the significance was maintained only for mutations in BRAF (OR 2.104, p = 0.038), MSI-high status (OR 2.003 p = 0.001), and N-ras (OR 3.000, p = 0.010) after the groups were divided by tumor site. CONCLUSION: Gene mutations in BRAF, MSI-high status, and N-ras differ according to gender among patients with colorectal cancer.

Upregulation of the growth arrest-specific-2 in recurrent colorectal cancers, and its susceptibility to chemotherapy in a model cell system.

Colorectal cancer (CRC) is one of the most common life-threatening malignances worldwide. CRC relapse markedly decreases the 5-year survival of patients following surgery. Aberrant expression of genes involved in pathways regulating the cell cycle, cell proliferation, or cell death are frequently reported in CRC tumorigenesis. We hypothesized that genes involved in CRC relapse might serve as prognostic indicators. We first evaluated the significance of gene sequences in the feces of patients with CRC relapse by consulting a public database. Tumorigenesis of target tissues was tested through tumor cell growth, cell cycle regulation, and chemotherapeutic efficacy. We found a highly significant correlation between CRC relapse and growth arrest-specific 2 (GAS2) gene expression. Based on cell models, the overexpressed GAS2 was associated with cellular growth rate, cell cycle regulation, and with chemotherapeutic sensitivity. Cell division was impaired by treating cells with 2-[4-(7-chloro-2-quinoxalinyloxy)phenoxy]-propionic acid (XK469), even when the cells were overexpressing GAS2. Thus, downregulation of GAS2 expression might control CRC relapse after curative resection. GAS2 could serve as a noninvasive marker from the feces of patients with prediagnosed CRC. Our findings suggest that GAS2 could have potential clinical applications for predicting early CRC relapse after radical resection, and that XK469 might impair tumor cell division by reducing GAS2 expression or blocking its cellular translocation. This will help in selecting the best therapeutic option, 5-fluorouracil in combination with XK469, for patients overexpressing GAS2 in CRC cells. Thus, GAS2 might act as a prognostic biomolecule and potential therapeutic target in patients with CRC relapse.

Molecular and Clinicopathological Differences by Age at the Diagnosis of Colorectal Cancer.

We compared the clinicopathological and molecular profiles between different age groups of sporadic colorectal cancer (CRC) patients (age <50, 56-60, 60-70, 70-80, and >80); 1475 CRC patients were enrolled after excluding 30 individuals with Lynch syndrome. The mutation spectra for APC, TP53, KRAS, PIK3CA, FBXW7, BRAF, NRAS, HRAS, TGFbR, Akt1, and PTEN were analyzed using polymerase chain reaction (PCR), followed by MassArray and microsatellite (MSI-high) analysis by performing genotyping. Male patients (74.1%) were significantly predominant to females (25.9%) in the older age group (70-80, >80). There was an insignificantly linear trend between TNM staging and age-onset of CRC diagnosis. Patients aged < 50 had 58.7% diseases in the advanced stages (Stage III: 36.5% and IV: 22.2% respectively), while this decreased to 40.2% (Stage III: 26.2% and IV; 14.0% respectively) in patients >80. The distributions of mutation frequency were similar in majority of the genes studied among different age groups. Additionally, patients aged <50 had significantly higher frequency of MSI-high, PTEN, and HRAS mutations than those of other groups. Age-onset at diagnosis significantly affected overall survival (HR = 1.46; 95% CI: 1.35-1.58), but not cancer-specific survival (HR = 1.08; 95% CI: 0.99-1.18) in multivariate analysis. In conclusion, molecular and clinicopathological differences were not as significant among different age groups of CRC patients as previously suspected.

Interleukin-1 Receptor Type 2 Acts with c-Fos to Enhance the Expression of Interleukin-6 and Vascular Endothelial Growth Factor A in Colon Cancer Cells and Induce Angiogenesis.

Interleukin-1 receptor type 2 (IL1R2) acts as a decoy receptor of exogenous IL-1; however, its intracellular activity is poorly understood. We previously demonstrated that IL1R2 intracellularly activates the expression of several proinflammatory cytokines and affects cell migration. In this study, we found that intracellular IL1R2 expression was increased in human colorectal cancer cells (CRCs) compared with normal colon cells. We also observed that the mRNA levels of IL1R2 were highly correlated with IL-6 in tumor tissues of CRC patients. By modulating its expression in CRC cells, we verified that enhanced IL1R2 expression transcriptionally activated the expression of IL-6 and VEGF-A. Conditioned medium harvested from IL1R2-overexpressing CRC cells contained higher levels of IL-6 and VEGF-A than that from vector control cells and significantly enhanced the proliferation, migration, and tube formation of cultured endothelial cells. We further demonstrated a positive association of intracellular IL1R2 levels with tumor growth and microvessel density in xenograft mouse models. These results revealed that IL1R2 activates the expression of angiogenic factors. Mechanistically, we revealed that IL1R2 complexes with c-Fos and binds to the AP-1 site at the IL-6 and VEGF-A promoters. Together, these results reveal a novel function of intracellular IL1R2 that acts with c-Fos to enhance the transcription of IL-6 and VEGF-A, which promotes angiogenesis in CRC.

Mutation Spectra of Common Cancer-Associated Genes in Different Phenotypes of Colorectal Carcinoma Without Distant Metastasis.

BACKGROUND: Colorectal cancer (CRC) is a heterogeneous disease caused by genetic and epigenetic alterations. This study aimed to describe the mutation frequency of 12 genes in different CRC phenotypes. METHODS: Patients who underwent surgery at the Taipei Veterans General Hospital during 2000-2010 for CRC (n = 1249) were enrolled. The endpoint was overall survival. The prognostic value was determined with the log-rank test and Cox regression analysis. RESULTS: We found 1836 mutations of 12 genes in 997 (79.8%) tumors. Mutations were most frequently in KRAS (485, 38.8%), TP53 (373, 29.9%), APC (363, 29.0%), and PIK3CA (179, 14.3%); 137 (11.0%) cancers had high microsatellite instability (MSI). Women had significantly higher high MSI (14.3%) and BRAF mutation (6.3%) frequencies. The abnormal MSI (21.7%) and KRAS (44.6%), BRAF (8.6%), PIK3CA (19.4%), AKT1 (2.2%), and TGF - ßR (9.6%) mutation frequencies were significantly higher in proximal colon cancer. The high MSI (35.6%) and BRAF (20.3%), TGF - ßR (18.6%), PTEN (5.1%), and AKT1 (3.4%) mutation frequencies were significantly higher in 59 (4.7%) poorly differentiated tumors. The high MSI (21.3%) and KRAS (51.9%), BRAF (8.3%), PIK3CA (25.0%), AKT1 (4.6%), and SMAD4 (8.3%) mutation frequencies were significantly higher in 108 mucinous tumors. TNM stage, lymphovascular invasion, and mucinous histology were significantly associated with patient outcomes in univariate and multivariate analyses. Only NRAS mutation (hazard ratio 1.59, 95% confidence interval 1.06-2.38) affected patient survival. CONCLUSIONS: Mutational spectra differ significantly between CRC subtypes, implying diverse carcinogenetic pathways. The NRAS mutation is important, despite its low frequency.

Transanal Total Mesorectal Excision Versus Laparoscopic Surgery for Rectal Cancer Receiving Neoadjuvant Chemoradiation: A Matched Case-Control Study.

BACKGROUND: Neoadjuvant chemoradiation therapy (nCRT) has been indicated for locally advanced rectal cancer. While utilization of laparoscopy in rectal cancer surgery has been popular in recent years, tumors receiving nCRT is still a surgical challenge. Transanal total mesorectal excision (TaTME) has emerged as a focused area of laparoscopic surgery that is becoming an increasingly acceptable approach in the field of rectal surgery. METHODS: Between December 2013 and April 2015, a total of 50 patients (38 males) with post-nCRT middle or lower rectal cancer who then underwent TaTME at two separate institutions were prospectively documented. Overall, 100 matched control cohorts who received conventional laparoscopic rectal surgery (LapTME) were simultaneously retrieved from a prospectively registered database. Four parameters of sex, age, clinical stage, and American Society of Anesthesiologists (ASA) score were matched for surgical outcomes, and short-term oncological results, including complications and pathological outcomes, were analyzed. RESULTS: Both the TaTME and LapTME groups received 5-fluorouracil-based chemotherapy and 5 weeks of long-course radiation therapy. Mean operative time for the TaTME group was 182.1 ± 55.4 min (156.6 ± 37.8 min in two-team-approach cases) and 178.7 ± 34.8 min for the LapTME group. The TaTME group yielded longer distal margin lengths. No significant differences were observed in blood loss, intraoperative complication rate, conversion rate, anastomosis type, and free circumferential margin rate. CONCLUSION: This matched case-control study demonstrated that TaTME is safe and feasible. Compared with LapTME, TaTME not only achieves identical circumferential margin status without compromising other operative and quality parameters but also benefits patients by achieving a longer distal margin. Thus, TaTME has the potential to become an option in managing irradiated rectal cancer.

Improved outcomes of colorectal cancer patients with liver metastases in the era of the multidisciplinary teams.

PURPOSE: The use of multidisciplinary teams (MDTs), which address colorectal cancer treatment planning through weekly regular group meetings, was begun in October 2007. We analyzed and compared the outcomes of colorectal cancer patients with metastatic disease before and after the era of MDTs. METHODS: From 2001 to 2010, 1075 patients who presented with stage IV disease and were treated in Taipei Veterans General Hospital were enrolled in the study. Among these patients, 439 (40.8%) were diagnosed after MDTs had been established. The percentage of patients receiving surgical treatment for metastatic disease was calculated and compared before and after MDTs were established, and the survival rate was compared using a log-rank test, with a significance of P < 0.05. RESULTS: A significantly improved survival rate in patients with stage IV disease was observed after establishment of MDTs, with the 3-year survival rate increasing from 25.6 to 38.2% (P < 0.001). Based on multivariate analysis, establishment of a MDT was an independent prognostic factor in patients with stage IV disease (hazard ratio = 0.74, 95% confidence interval = 0.624∼0.866, P < 0.001). The percentage of liver resection in patients with liver metastasis increased from 19.6 to 35.2% after the establishment of MDTs, whereas the percentage of lung resection in patients with lung metastasis remained stationary from 12.4 to 14.3%. CONCLUSIONS: In the era of MDTs, intensive cooperation between different specialists has increased the referral rate for metastasectomy, resulting in significantly improved outcomes of colorectal patients in initial stage IV disease.

Elevated serum alpha-fetoprotein in poorly differentiated adenocarcinoma with neuroendocrine differentiation of the ascending colon: a case report.

BACKGROUND: Colorectal cancer (CRC) is the most common form of cancer and the third leading cause of death in Taiwan. Serum alpha-fetoprotein (AFP) has been extensively used as a biomarker for hepatocellular carcinoma (HCC) and yolk sac tumors. CASE PRESENTATION: This case report presents a 90-year-old woman with right abdominal pain and poor appetite for 1 week. The computed tomography (CT) showed wall thickening in the proximal ascending colon with ruptured appendicitis. Preoperative serum AFP was high. There was no definite liver metastasis or other abnormal findings in the hepatobiliary systems. After initial empirical antibiotic treatment, we performed laparoscopic right hemicolectomy. The pathological assessment was poorly differentiated adenocarcinoma with neuroendocrine differentiation in the ascending colon. The tumor cells did not produce AFP. Amazingly, the follow-up serum AFP level 1 month after the surgery declined to normal range. The patient had an uneventful course after the surgery and was free of recurrence or metastasis within 5 months of follow-up. CONCLUSIONS: AFP may be a useful tumor marker in poorly differentiated colorectal cancer with neuroendocrine component patients and a prediction of early treatment response.

Clinical Relevance of Plasma DNA Methylation in Colorectal Cancer Patients Identified by Using a Genome-Wide High-Resolution Array.

BACKGROUND: DNA methylation is a potential tumor marker for several cancers, including colorectal cancer (CRC), because of its heritable and stable characteristics. METHODS: Using a high-resolution, genome-wide approach, we epigenotyped >450,000 CpG sites in tumor and adjacent non-tumor tissues from 23 microsatellite instability (MSI)/microsatellite stability (MSS) CRC cases. Using matrix-assisted laser desorption ionization-time of flight mass spectrometry, the methylation status of five frequently hypermethylated genes were confirmed in 75 independent CRC series and 353 CRC patients with available plasma. RESULTS: Compared with non-tumor tissues, 13 MSI tumors had 34,836 (7 %) aberrant methylation sites, 87 % of which were hypermethylated. In contrast, only 9,806 (2 %) differentially methylated sites were identified in ten MSS cases (62 % hypermethylated). In both MSI and MSS, 228 promoter-associated CpG islands were hypermethylated, with AGBL4, ZNF625, MDFI, TWIST1, and FLI1 being most frequently hypermethylated. In an independent set of 35 MSI and 40 MSS cases, the methylation status of these five genes significantly differed between tumor and adjacent non-tumor tissues. Of 353 CRC patients, 230 (65.2 %), 232 (65.7 %), and 247 (70.0 %) had AGBL4, FLI1, and TWIST1 promoter hypermethylation in circulating cell-free DNA, respectively. In patients without metastasis, the sensitivity of any two or three hypermethylation markers was 52.8-57.8 and 27.9-38.9 %, respectively. The sensitivity of any two or three markers was significantly high in patients with stage IV disease (73.0 and 55.6 %, respectively). The prognostic value of these epimarkers was inconclusive. CONCLUSION: DNA methylation patterns differed in CRC subtypes. The identified hypermethylation markers in CRC patients may have good sensitivity in different CRC stages.