Mechanisms of oncogenesis in colon versus rectal cancer

NMR-based metabolomics combined with metabolic pathway analysis reveals metabolic heterogeneity of colorectal cancer tissue at different anatomical locations and stages

Colorectal cancer (CRC) still remains the leading cause of cancer death worldwide. This study aimed to profile the metabolic differences of colorectal cancer tissues (CCT) at different stages and sites, as compared with their distant noncancerous tissues (DNT), to investigate the temporal and spatial heterogeneities of metabolic characterization. Our NMR-based metabolomics fingerprinting revealed that many of the metabolite levels were significantly altered in CCT compared to DNT and esophageal cancer tissues, indicating deregulations of glucose metabolism, one-carbon metabolism, glutamine metabolism, amino acid metabolism, fatty acid metabolism, TCA cycle, choline metabolism, and so forth. A total of five biomarker metabolites, including glucose, glutamate, alanine, valine and histidine, were identified to distinguish between early and advanced stages of CCT. Metabolites that distinguish the different anatomical sites of CCT include glucose, glycerol, glutamine, inositol, succinate, and citrate. Those significant metabolic differences in CRC tissues at different pathological stages and sites suggested temporal and spatial heterogeneities of metabolic characterization in CCT, providing a metabolic foundation for further study on biofluid metabolism in CRC early detection.

Radioresistance in rectal cancer: can nanoparticles turn the tide?

Rectal cancer accounts for over 35% of the worldwide colorectal cancer burden representing a distinctive subset of cancers from those arising in the colon. Colorectal cancers exhibit a continuum of traits that differ with their location in the large intestine. Due to anatomical and molecular differences, rectal cancer is treated differently from colon cancer, with neoadjuvant chemoradiotherapy playing a pivotal role in the control of the locally advanced disease. However, radioresistance remains a major obstacle often correlated with poor prognosis. Multifunctional nanomedicines offer a promising approach to improve radiotherapy response rates, as well as to increase the intratumoral concentration of chemotherapeutic agents, such as 5-Fluorouracil. Here, we revise the main molecular differences between rectal and colon tumors, exploring the complex orchestration beyond rectal cancer radioresistance and the most promising nanomedicines reported in the literature to improve neoadjuvant therapy response rates.

Somatic pharmacogenomics in the treatment prognosis of locally advanced rectal cancer patients: a narrative review of the literature

INTRODUCTION

Standard treatment for patients with locally advanced rectal cancer (LARC) includes neoadjuvant chemoradiotherapy (nCRT) with fluoropyrimidines, followed by surgical excision. The newly introduced therapeutic strategies propose intensified regimens or more conservative approaches based on risk stratification algorithms that currently include clinicoradiological criteria but not molecular variables. How to better stratify patients is a burning clinical question, and pharmacogenomics may prove useful in identifying new genetic markers that could be incorporated into clinical algorithms to personalize nCRT. An emerging area could be the evaluation of somatic mutations as potential genetic markers that correlate with patient prognosis. Tumor mutations in the RAS/BRAF genes, as well as microsatellite instability (MSI) status, are currently used in treatment selection for colorectal cancer (CRC); however, their clinical value in LARC is still unclear.

AREA COVERED

This literature review discusses the relevant findings on the prognostic role of mutations in the key oncogenes RAS, KRAS, BRAF, PIK3CA, SMAD4 and TP53, including MSI status in LARC patients treated with nCRT.

EXPERT OPINION

KRAS proved to be the most promising marker, consistently associated with poorer disease-free survival and overall survival. Therefore, KRAS could be a good candidate for integration into the risk stratification algorithm to develop a personalized treatment.

Molecular Landscape and Therapeutic Strategies against Colorectal Cancer

Colorectal cancer (CRC) is the second leading cause of cancer deaths worldwide. Although the overall incidence of CRC is decreasing, the incidence of young-onset CRC, characterized by a diagnosis of CRC before age 50, is increasing. Outcomes for CRC patients are improving, partly due to comprehensive molecular characterization of tumors and novel therapeutic strategies. Advances in genomic and transcriptomic analyses using blood- and tumor-tissue-based sequencing have facilitated identification of distinct tumor subtypes harboring unique biological characteristics and therapeutic vulnerabilities. These insights have led to the development and incorporation of targeted therapies and immunotherapy in CRC treatment. In this review, we discuss the molecular landscape and key oncogenes/tumor suppressors contributing to CRC tumorigenesis, metastasis, and therapeutic resistance. We also discuss personalized therapeutic strategies for subsets of CRC patients and provide an overview of evolving novel treatments being evaluated in clinical trials.

The association of diet-dependent acid load with colorectal cancer risk: a case-control study in Korea

Acid-base disequilibrium is a contributor to cancer development because it affects molecular activities such as insulin-like growth factor 1 levels and adiponectin production. However, evidence of an association of diet-induced acid-base imbalance with colorectal cancer (CRC) is limited. We examined whether colorectal carcinogenesis is attributable to a diet with a high acid load. We recruited a total of 923 CRC cases and 1846 controls at the National Cancer Center in Korea for inclusion in a case-control study. We collected information on nutrient intake and specific clinical parameters of CRC by using a semiquantitative FFQ and medical records, respectively. Potential renal acid load (PRAL) and net endogenous acid production (NEAP) were used to estimate diet-dependent acid load. We used an unconditional logistic regression model to analyse the association. Dietary acid load scores had a positive association with the odds of CRC (OR = 2·31 (95 % CI 1·79, 2·99) and OR = 2·14 (95 % CI 1·66, 2·76) for PRAL and NEAP, respectively, Pfor trend < 0·001). A stronger positive association was observed for females (OR = 3·09, 95 % CI 1·93, 4·94) than for males (OR = 1·71, 95 % CI 1·27, 2·31). Furthermore, acidogenic diets appeared to affect rectal cancer more strongly than colon cancer in females. Our study contributes to reinforcing epidemiological evidence regarding a detrimental effect of acidogenic diets on colorectal carcinogenesis. Thus, it is important to pay attention to the balance of acidogenic (e.g. poultry and red meat) and alkalinogenic foods (e.g. fruits and vegetables) in CRC prevention, especially for females.

A novel EGFR inhibitor, HNPMI, regulates apoptosis and oncogenesis by modulating BCL-2/BAX and p53 in colon cancer

BACKGROUND AND PURPOSE

Colorectal cancer (CRC) is the second most lethal disease, with high mortality due to its heterogeneity and chemo-resistance. Here, we have focused on the epidermal growth factor receptor (EGFR) as an effective therapeutic target in CRC and studied the effects of polyphenols known to modulate several key signalling mechanisms including EGFR signalling, associated with anti-proliferative and anti-metastatic properties.

EXPERIMENTAL APPROACH

Using ligand- and structure-based cheminformatics, we developed three potent, selective alkylaminophenols, 2-[(3,4-dihydroquinolin-1(2H)-yl)(p-tolyl)methyl]phenol (THTMP), 2-[(1,2,3,4-tetrahydroquinolin-1-yl)(4-methoxyphenyl)methyl]phenol (THMPP) and N-[2-hydroxy-5-nitrophenyl(4'-methylphenyl)methyl]indoline (HNPMI). These alkylaminophenols were assessed for EGFR interaction, EGFR-pathway modulation, cytotoxic and apoptosis induction, caspase activation and transcriptional and translational regulation. The lead compound HNPMI was evaluated in mice bearing xenografts of CRC cells.

KEY RESULTS

Of the three alkylaminophenols tested, HNPMI exhibited the lowest IC50 in CRC cells and potential cytotoxic effects on other tumour cells. Modulation of EGFR pathway down-regulated protein levels of osteopontin, survivin and cathepsin S, leading to apoptosis. Cell cycle analysis revealed that HNPMI induced G0/G1 phase arrest in CRC cells. HNPMI altered the mRNA for and protein levels of several apoptosis-related proteins including caspase 3, BCL-2 and p53. HNPMI down-regulated the proteins crucial to oncogenesis in CRC cells. Assays in mice bearing CRC xenografts showed that HNPMI reduced the relative tumour volume.

CONCLUSIONS AND IMPLICATIONS

HNPMI is a promising EGFR inhibitor for clinical translation. HNPMI regulated apoptosis and oncogenesis by modulating BCL-2/BAX and p53 in CRC cell lines, showing potential as a therapeutic agent in the treatment of CRC.

Predictive and Prognostic Value of Oncogene Mutations and Microsatellite Instability in Locally-Advanced Rectal Cancer Treated with Neoadjuvant Radiation-Based Therapy: A Systematic Review and Meta-Analysis

Markers of pathological complete response (pCR) to preoperative radiation-based therapy in locally advanced rectal cancer (LARC) are strongly needed. This meta-analysis aimed at elucidating the predictive/prognostic role of tumor markers in LARC. We systematically reviewed the impact of RAS, TP53, BRAF, PIK3CA, and SMAD4 mutations and MSI status on response (pCR, downstaging) and prognosis (risk of recurrence, survival) in LARC according to PRISMA guidelines and the PICO model. PubMed, Cochrane Library, and Web of Science Core Collection were systematically searched to identify relevant studies published before October 2022. KRAS mutations were significantly associated with the risk of not achieving pCR after preoperative treatment (summary OR = 1.80, 95% CI: 1.23-2.64). This association was even more significant in patients not receiving cetuximab (summary OR = 2.17, 95% CI: 1.41-3.33) than in patients receiving cetuximab (summary OR = 0.89, 95% CI: 0.39-20.05). MSI status was not associated with pCR (summary OR = 0.80, 95% CI: 0.41-1.57). No effect of KRAS mutation or MSI status on downstaging was detected. Meta-analysis of survival outcomes was not possible due to the large heterogeneity among studies in endpoint assessment. The minimum number of eligible studies to assess the predictive/prognostic role of TP53, BRAF, PIK3CA, and SMAD4 mutations was not reached. KRAS mutation, but not MSI status, proved to be a detrimental marker for response to preoperative radiation-based therapy in LARC. Translating this finding into the clinic could improve the management of LARC patients. More data are needed to clarify the clinical impact of TP53, BRAF, PIK3CA, and SMAD4 mutations.

Bile acids as carcinogens in the colon and at other sites in the gastrointestinal system

Colon cancer incidence is associated with a high-fat diet. Such a diet is linked to elevated levels of bile acids in the gastrointestinal system and the circulation. Secondary bile acids are produced by microorganisms present at high concentrations in the colon. Recent prospective studies and a retrospective study in humans associate high circulating blood levels of secondary bile acids with increased risk of colon cancer. Feeding mice a diet containing a secondary bile acid, so their feces have the bile acid at a level comparable to that in the feces of humans on a high-fat diet, also causes colon cancer in the mice. Studies using human cells grown in culture illuminate some mechanisms by which bile acids cause cancer. In human cells, bile acids cause oxidative stress leading to oxidative DNA damage. Increased DNA damage increases the occurrence of mutations and epimutations, some of which provide a cellular growth advantage such as apoptosis resistance. Cells with such mutations/epimutations increase by natural selection. Apoptosis, or programmed cell death, is a beneficial process that eliminates cells with unrepaired DNA damage, whereas apoptosis-resistant cells are able to survive DNA damage using inaccurate repair processes. This results in apoptosis-resistant cells having more frequent mutations/epimutations, some of which are carcinogenic. The experiments on cultured human cells have provided a basis for understanding at the molecular level the human studies that recently reported an association of bile acids with colon cancer, and the mouse studies showing directly that bile acids cause colon cancer. Similar, but more limited, findings of an association of dietary bile acids with other cancers of the gastrointestinal system suggest that understanding the role of bile acids in colon carcinogenesis may contribute to understanding carcinogenesis in other organs.

Role of Dairy Foods, Fish, White Meat, and Eggs in the Prevention of Colorectal Cancer: A Systematic Review of Observational Studies in 2018-2022

There is limited evidence to support the relationship between the consumption of animal-source foods other than red meat and processed meat and colorectal cancer (CRC) risk. We aimed to examine the recent available evidence from observational studies about the association between these food groups’ intake and CRC risk. For this systematic review, we searched the PubMed database for the last five years. A total of fourteen cohort studies and seven case−control studies comprising a total of >60,000 cases were included. The studies showed a consistent significant decrease in CRC risk, overall and by subsites, associated with a high consumption of total dairy products. Less strong effects associated with the consumption of any subtype of dairy product were observed. Fish consumption, overall and by subtypes (oily or non-oily and fresh or canned), showed a mild inverse association with CRC risk. The association between white meat and egg intake and CRC risk was low and based on a small number of studies; thus, these findings should be interpreted with caution. In conclusion, a high consumption of total dairy products was associated with a lower CRC risk. However, evidence for fish, white meat, and eggs and the CRC risk were not as strong.

Microsatellite instability in rectal cancer: what does it mean? A study of two randomized trials and a systematic review of the literature

Currently, compelling evidence illustrates the significance of determining microsatellite instability (MSI) in colorectal cancer (CRC). The association of MSI with proximal CRC is well established, however, its implications in patients with rectal cancer remain undefined. We therefore aimed to determine the role of MSI with respect to incidence and outcome in patients with rectal cancer, by the examination of patients from two prospective phase III trials: TME trial and PROCTOR-SCRIPT trial (n=1250). No differences in terms of overall survival (HR 1.00, 95%CI 0.69-1.47) and disease-free survival (HR 1.00, 95%CI 0.68-1.45) were observed in patients with MSI compared to microsatellite stable (MSS) rectal cancer. In addition, we performed a literature review to evaluate the overall prevalence, the effect on survival and the response to neo-adjuvant treatment in patients with MSI rectal cancer compared with MSS rectal cancer. The total number of MSI cases in the included studies (including our own) was 1220 (out of 16526 rectal cancer patients), with an overall prevalence of 6.7% (SE 1.19%). Both for overall survival as for disease-free survival there was no impact of MSI status on prognosis (HR 1.00, 95%CI 0.77-1.29 and HR 0.86, 95% CI 0.60-1.22, respectively). The risk ratio for downstaging and pCR showed also no impact of MSI status (RR 1.15, 95% CI 0.86-1.55 and RR 0.81, 95% CI 0.54-1.22 respectively). In conclusion, rectal cancer patients with MSI form a distinct and rare subcategory, however, there is no prognostic effect of MSI in rectal cancer patients.

The "Immunoscore" in rectal cancer: could we search quality beyond quantity of life?

Because of the function and anatomical environment of the rectum, therapeutic strategies for local advanced rectal cancer (LARC) must deal with two challenging stressors that are a high-risk of local and distal recurrences and a high-risk of poor quality of life (QoL). Over the last three decades, advances in screening tests, therapies, and combined-modality treatment options and strategies have improved the prognosis of patients with LARC. However, owing to the heterogeneous nature of LARC and genetic status, the patient may not respond to a specific therapy and may be at increased risk of side-effects without the life-prolonging benefit. Indeed, each therapy can cause its own side-effects, which may worsen by a combination of treatments resulting in long-term poor QoL. In LARC, QoL has become even more essential with the increasing incidence of rectal cancer in young individuals. Herein, we analyzed the value of the Immunoscore-Biopsy (performed on tumor biopsy at diagnosis) in predicting outcomes, alone or in association with clinical and imaging data, for each therapy used in LARC.

Immune cell infiltration in colonic cancer: correlation between biopsy and surgical specimens

Infiltration of CD3+ and CD8+ T cells in tumour biopsies of patients with colonic cancer correlated positively with CD3+ and CD8+ T cell infiltration in matched tumour surgical specimens. This opens new perspectives in the potential of tumour biopsies for prognosis and treatment decisions.

Predictive value of changes in the level of carbohydrate antigen 19-9 in patients with locally advanced rectal cancer treated with neoadjuvant chemoradiotherapy

AIM

The aim of this work was to explore the predictive value of changes in the level of carbohydrate antigen 19-9 (CA19-9) after neoadjuvant chemoradiotherapy (nCRT) and after surgery in patients with locally advanced rectal cancer (LARC).

METHOD

Patients with LARC who underwent nCRT and radical surgery (between 2011 and 2016) were divided into three groups according to pre-nCRT and post-nCRT CA19-9 levels as follows: normal pre-nCRT CA19-9 (normal CA19-9 group), elevated pre-nCRT and normal post-nCRT CA19-9 (normalized group) and elevated pre-nCRT and elevated post-nCRT CA19-9 (nonnormalized group). The pathological nCRT response criteria included ypCR and downstaging (ypStages 0-I). Recurrence-free survival (RFS) and overall survival (OS) were analysed.

RESULTS

A total of 721 patients were identified. The normal CA19-9 group was significantly associated with ypCR (n = 159) and downstaging (n = 347) (P < 0.05). The normalized group (n = 76) had worse RFS and OS than the normal CA19-9 group (n = 622) and better RFS and OS than the nonnormalized group (n = 23) (5-year RFS 47.0% vs 66.9% vs 81.5%, P < 0.001; 5-year OS 47.0% vs 75.4% vs 85.0%, P < 0.001). In multivariate analysis, CA19-9 group and ypTNM stage were independent predictors of RFS and OS. Moreover, for the 23 patients with elevated post-nCRT CA19-9 levels, the RFS and OS of patients with normalized postoperative CA19-9 levels were significantly better than those of patients with elevated postoperative CA19-9 levels (P < 0.05).

CONCLUSION

Following nCRT, changes in the CA19-9 level are a strong prognostic marker for long-term survival, and they may be helpful in the selection of patients who prefer more conservative surgery after chemoradiotherapy.

Primary tumour location is an important prognostic factor in colorectal cancer liver metastases following radiofrequency ablation

AIM

To examine the outcomes and different prognoses for colorectal cancer patients with liver metastases (CRCLM) treated with radiofrequency ablation (RFA) based on the origin of the primary tumour (rectum versus colon).

MATERIALS AND METHODS

Patients diagnosed with CRCLM from July 2011 to June 2018 were assessed in the study. The study included 114 patients with 176 lesions. All of the patients underwent RFA of their CRCLM. The overall survival (OS) and progression-free survival (PFS) were assessed with Kaplan-Meier survival function estimate curves and Cox regression analysis between the group of patients with rectal cancer liver metastases (RCLM) and colon cancer liver metastases (CCLM).

RESULTS

Patients with RCLM exhibited worse OS and PFS than those with CCLM. The 1-, 2-, and 3-year OS rates were 87.5%, 75%, and 54.2% in the RCLM group and 93.9%, 87.8%, and 81.8% in the CCLM group (p=0.001), respectively. The 1-, 2-, and 3-year PFS rates were 43.7%, 22.9%, and 20.8% in the RCLM group and 57.6%, 45.4%, and 36.5% in the CCLM group (p=0.001), respectively. Multivariate analysis showed that primary tumour location, carcinoembryonic antigen (CEA), and response to pre-ablation chemotherapy were independent variables for OS and PFS. The N state of the primary tumour also had a significant impact on OS.

CONCLUSION

This study showed that patients with CCLM had better prognoses than those with RCLM following RFA treatment. If patients intend to undergo RFA for CRCLM, the location of the primary tumour should be considered in the assessment of long-term therapeutic effects.

Plasma protein expression differs between colorectal cancer patients depending on primary tumor location

Colorectal cancer (CRC) includes tumors in the right colon, left colon, and rectum, although they differ significantly from each other in aspects such as prognosis and treatment. Few previous mass spectrometry-based studies have analyzed differences in protein expression depending on the tumor location. In this study, we have used mass spectrometry-based proteomics to analyze plasma samples from 83 CRC patients to study if differences in plasma protein expression can be seen depending on primary tumor location (right colon, left colon, or rectum). Differences were studied between the groups both regardless of and according to tumor stage (II or III). Large differences in plasma protein expression were seen, and we found that plasma samples from patients with rectal cancer separated from samples from patients with colon cancer when analyzed by principal component analysis and hierarchical clustering. Samples from patients with cancer in the right and left colon also tended to separate from each other. Pathway analysis discovered canonical pathways involved in lipid metabolism and inflammation to be enriched. This study will help to further define CRC as distinct entities depending on tumor location, as shown by the widespread differences in plasma protein profile and dysregulated pathways.

Associations among dietary seaweed intake, c-MYC rs6983267 polymorphism, and risk of colorectal cancer in a Korean population: a case-control study

PURPOSE

The effects of seaweed compounds have been studied in relation to colorectal cancer (CRC) based on their ability to modulate carcinogen metabolism in vivo and in vitro. However, no epidemiological studies on the interaction between edible seaweed and genetic variants relevant to CRC have been reported. This study examined the associations among dietary seaweed intake (gim, miyeok, and dashima), single-nucleotide polymorphisms (SNPs; rs6983267, rs7014346, and rs719725), and CRC risk in a Korean population.

METHODS

The participants comprised 923 CRC patients and 1846 controls who visited the National Cancer Center Korea. We used a Semiquantitative Food Frequency Questionnaire and genotyped SNPs using genomic DNA samples.

RESULTS

The intake of total seaweed, miyeok, and dashima showed a significant inverse association with CRC risk after adjusting for potential confounding factors (total seaweed odds ratio (OR) [95% CI] = 0.65 [0.50-0.85], P for trend < 0.001; miyeok = 0.82 [0.62-1.09], P for trend < 0.05; dashima = 0.58 [0.44-0.76], P for trend < 0.001, highest vs. lowest tertile). We confirmed that the homozygous T/T allele of rs6983267 c-MYC indicated an interaction between dietary seaweed intake and both overall CRC and rectal cancer (CRC OR [95% CI] = 0.52 [0.34-0.81], P for interaction = 0.015; rectal cancer = 0.45 [0.25-0.79], P for interaction = 0.007, T/T carriers with high total seaweed intake vs. T/T carriers with low total seaweed intake).

CONCLUSIONS

This study provides evidence of the effect of dietary seaweed intake on CRC risk with respect to c-MYC gene variants.

A Propensity Score-adjusted Analysis of the Effects of Ubiquitin E3 Ligase Copy Number Variation in Peripheral Blood Leukocytes on Colorectal Cancer Risk

Background: The ubiquitin ligases E3 (E3s) plays a key role in the specific protein degradation in many carcinogenic biological processes. Colorectal cancer (CRC) development may be affected by the copy number variation (CNV) of E3s. Prior studies may have underestimated the impact of potential confounding factors' effects on the association between gene CNV and CRC risk, and CRC risk predictive model integrating gene CNV patterns is lacking. Our research sought to assess the genes CNVs of MDM2, SKP2, FBXW7, β-TRCP, and NEDD4-1 and CRC risk by using propensity score (PS) adjustment and developing models that integrate CNV patterns for CRC risk predictions.

Methods: This study comprising 1036 participants used traditional regression and different PS techniques to adjust the confounding factors to evaluate the relationships between five gene CNVs and CRC risk, and to establish a CRC risk predictive model. The AUC was applied to evaluate the effect of the model. The categorical net reclassification improvement (NRI) and the integrated discrimination improvement (IDI) were analyzed to evaluate the discriminatory accuracy improvement among the models.

Results: Compared to variable adjustment, the odds ratios (ORs) tended to be conservative and accurate with narrow confidence intervals (CIs) after PS adjustment. After PS adjustment, MDM2 amplification was related to increased CRC risk (Amp-pattern: OR = 8.684, 95% CI: 1.213-62.155, P = 0.031), whereas SKP2 deletion and the (del+amp) genotype were associated with reduced CRC risk (Del-pattern: OR = 0.323, 95% CI: 0.106-0.979, P = 0.046; Var-pattern: OR = 0.339, 95% CI: 0.135-0.854, P = 0.024). The predictive model integrating the gene CNV pattern could correctly reclassify 1.7% of the subjects.

Conclusions: MDM2 amplification and SKP2 CNVs are associated with increased and decreased CRC risk, respectively; abnormal CNV-integrated model is more precise for predicting CRC risk. Further studies are needed to verify these encouraging outcomes.

The roles of p53 and XPO1 on colorectal cancer progression in Yemeni patients

Background

The colorectal cancer (CRC) tumorigenesis is driving by genetic alterations leading to changes in protein expression such as p53. The p53 is frequently expressed in CRC and its association with clinicopathological features is still controversial. Moreover, accumulated evidence suggests that both p53 and nuclear exporter protein, exportin 1 (XPO1), are working in reciprocal manner may lead to loss of p53 nuclear localization and enhance cancer progression through hyperactive nuclear export. Accordingly, the present study aimed to evaluate the expression of p53 in CRC Yemeni patients and to explore the association between the p53 and XPO1 coexpression in relation to clinicopathological features.

Methods

A series of 40 formalin fixed paraffin embedded (FFPE) tissue blocks taken from CRC patients that diagnosed as adenocarcinoma were prospectively collected and then analyzed for p53 and XPO1 expression by immunohistochemistry (IHC). The patients and tumor clinicopathological characteristics were retrieved from the histopathology reports and the P value <0.05 were considered statistically significant.

Results

The p53 expression was observed in 60% (24/40) of CRC tumor samples. Significantly, the p53 expression was noted in 72.4% (21/29) of the left side compared to 27.3% (3/11) of the right side colon tumors (P=0.014). Furthermore, p53 expression was positively and significantly correlated with well-but not moderate- or poorly-differentiated tumors (P=0.023). No significant difference was observed between the p53 expression and age, gender and tumor size. Regarding the XPO1 expression, the p53 expression didn't show an association with XPO1 expression. The coexpression of p53 and XPO1 analysis revealed that 100% (11/11) tumors with negative p53 and positive XPO1 coexpression was noted with lymph node metastasis with significant difference (P=0.003) and more frequently observed in moderate-or poorly- differentiated tumors.

Conclusions

The loss of p53 accompanied with increased XPO1 expressions was associated with the progression of histopathological features of CRC Yemeni patients. Further studies are needed to elucidate the p53 genetic mutations in relation to the XPO1 coexpression in CRC prognosis.

Increased Levels of Genomic Instability and Mutations in Homologous Recombination Genes in Locally Advanced Rectal Carcinomas

Pre-operative 5-fluoracil-based chemoradiotherapy (nCRT) is the standard treatment for patients with locally advanced rectal cancer (LARC). Patients with pathological complete response (pCR–0% of tumor cells in the surgical specimen after nCRT) have better overall survival and lower risk of recurrence in comparison with incomplete responders (pIR). Predictive biomarkers to be used for new therapeutic strategies and capable of stratifying patients to avoid overtreatment are needed. We evaluated the genomic profiles of 33 pre-treatment LARC biopsies using SNP array and targeted-next generation sequencing (tNGS). Based on the large number of identified genomic alterations, we calculated the genomic instability index (GII) and three homologous recombination deficiency (HRD) scores, which have been reported as impaired DNA repair markers. We observed high GII in our LARC cases, which was confirmed in 165 rectal cancer cases from TCGA. Patients with pCR presented higher GII compared with pIR. Moreover, a negative correlation between GII and the fraction of tumor cells remaining after surgery was observed (ρ = –0.382, P = 0.02). High HRD scores were detected in 61% of LARC, of which 70% were incomplete responders. Using tNGS (105 cancer-related genes, 13 involved in HR and 5 in mismatch repair pathways), we identified 23% of cases with mutations in HR genes, mostly in pIR cases (86% of mutated cases). In agreement, the analysis of the TCGA dataset (N = 145) revealed 21% of tumors with mutations in HR genes. The HRD scores were shown to be predictive of better response to PARP-inhibitors and platinum-based chemotherapy in breast and ovarian cancer. Our results suggest that the same strategy could be applied in a set of LARC patients with HRD. In conclusion, we identified high genomic instability in LARC, which was related to alterations in the HR pathway, especially in pIR. These findings suggest that patients with impaired HRD would clinically benefit from PARP-inhibitors and platinum-based therapy.

Linkage analysis revealed risk loci on 6p21 and 18p11.2-q11.2 in familial colon and rectal cancer, respectively

Colorectal cancer (CRC) is one of the major cancer types in the western world including Sweden. However, known genetic risk factors could only explain a limited part of heritability of the disease. Moreover, colon and rectal cancers are habitually discussed as one entity, colorectal cancer, although different carcinogenesis has been recognized. A genome-wide linkage scan in 32 colon- and 56 rectal cancer families from Sweden was performed based on 475 non-FAP/HNPCC patients genotyped using SNP arrays. A maximum HLOD of 2.50 at locus 6p21.1-p12.1 and a HLOD of 2.56 at 18p11.2 was obtained for colon and rectal cancer families, respectively. Exome sequencing over the regions of interest in 12 patients from six families identified 22 and 25 candidate risk variants for colon and rectal cancer, respectively. Haplotype association analysis in the two regions was carried out between additional 477 familial CRC cases and 4780 controls and suggested candidate haplotypes possibly associated with CRC risk. This study suggested two new linkage regions for colon cancer and rectal cancer with candidate predisposing variants. Further studies are required to elucidate the pathogenic mechanism of these regions and to pinpoint the causative genes.

Milk and risk of colorectal, colon and rectal cancer in the Norwegian Women and Cancer (NOWAC) Cohort Study

According to World Cancer Research Fund International/American Institute for Cancer Research, it is 'probable' that dairy products decrease the risk of colorectal cancer (CRC). However, meta-analyses restricted to women have not shown associations between milk intake and risk of CRC. The aim of this study was to examine the association between milk intake and risk of CRC, colon cancer and rectal cancer among women. Data from 81 675 participants in the Norwegian Women and Cancer Cohort Study were included, and multivariable Cox proportional hazard regression models were used to investigate milk intake using two different analytical approaches: one that included repeated measurements and one that included baseline measurements only (872 and 1084 CRC cases, respectively). A weak inverse association between milk intake and risk of colon cancer may be indicated both in repeated measurements analyses and in baseline data analyses. Hazard ratios (HR) for colon cancer of 0·80 (95 % CI 0·62, 1·03, P trend 0·07) and 0·81 (95 % CI 0·64, 1·01, P trend 0·03) and HR for rectal cancer of 0·97 (95 % CI 0·67, 1·42, P trend 0·92) and 0·71 (95 % CI 0·50, 1·01, P trend 0·03) were found when comparing the high with the no/seldom milk intake group in energy-adjusted multivariable models. Our study indicates that there may be a weak inverse association between milk intake and risk of colon cancer among women. The two analytical approaches yielded different results for rectal cancer and hence CRC. Our study indicates that the use of single or repeated measurements in analyses may influence the results.

Association between Cardiovascular Risk and Diabetes with Colorectal Neoplasia: A Site-Specific Analysis

Several studies have shown site-specific differences in colorectal cancer (CRC) with respect to the risk factors. CRC was shown to be associated with cardiovascular risk (CVR) factors, but site-specific variations have not been investigated so far. This study aimed to assess the associations between the prevalence and subsite-specific differences of colorectal neoplasia and established CVR scores or known coronary artery disease (CAD) in a large asymptomatic European screening cohort (N = 2098). Participants underwent simultaneous screening colonoscopy and CVR evaluation, using the Framingham Risk Score and Heart Score. Lesions found in the colonoscopy were classified by location (proximal/distal colon or rectum). More neoplasias were found in the proximal versus the distal colon (p < 0.001). The Framingham Risk Score and Heart Score showed incremental risk for colorectal adenoma, across the tertiles in the proximal and the distal colon (p < 0.001). The prevalence of adenomas in the rectum was much lower, but also here, incremental risk could be shown for the Framingham Risk but not the Heart Risk Score tertiles. Prevalence of adenomas in the proximal colon was higher in subjects with type 2 diabetes (T2DM) (p = 0.006), but no association was found between adenomas and T2DM in the distal colon (p = 0.618) and the rectum (p = 0.071). Males had a higher CVR and more findings, in the screening colonoscopy, as compared to females, however, no site-specific differences were noted. Patients with known CAD and high CVR have an increased risk of colorectal neoplasia in both the proximal and distal colon. Patients with T2DM have a higher risk for neoplasia in the proximal colon.

The association between the TP53 Arg72Pro polymorphism and colorectal cancer: An updated meta-analysis based on 32 studies

Several previous studies evaluated the association between the Arg72Pro (rs1042522) polymorphism in the TP53 tumor suppressor gene and colorectal cancer (CRC). However, the results are conflicting. This meta-analysis aimed to shed new light on the precise association between TP53 variants and CRC. We analyzed 32 published case-control studies involving 8,586 cases and 10,275 controls using crude odd ratios (ORs) with 95% confidence intervals (CIs). The meta-analysis was performed using a fixed-effect or random-effects model, as appropriate. We found that the TP53 Arg72Pro polymorphism was not significantly associated with CRC risk in the overall population. However, subgroup analysis based on ethnicity revealed an increased risk of CRC among Asians (CC vs. GC+GG: OR=1.22, 95% CI: 1.02-1.45), and similar results were found for rectal cancer (CC vs. GC+GG: OR=1.34, 95% CI: 1.120-1.62). These results suggest that the TP53 Arg72Pro polymorphism CC genotype may contribute to an increased risk of CRC, especially for rectal cancer and among Asians.

Flavan-3-ols consumption and cancer risk: A meta-analysis of epidemiologic studies

Although numerous in vitro studies and animal model data have suggested that flavan-3-ols, the most common subclass of flavonoids in the diet, may exert protective effects against cancer, epidemiologic studies have reported inconclusive results for the association between flavan-3-ols intake and cancer risk. Therefore, we conducted this meta-analysis of epidemiologic studies to investigate the preventive effects of flavan-3-ols on various types of cancers. A total of 43 epidemiologic studies, consisting of 25 case-control and 18 prospective cohort studies, were included. A significant inverse association was shown between flavan-3-ols intake and the risk of overall cancer (relative risk (RR) 0.935, 95%CI: 0.891-0.981). When cancer types were separately analyzed, a statistically significant protective effect of flavan-3-ols consumption was observed in rectal cancer (RR 0.838, 95%CI: 0.733-0.958), oropharyngeal and laryngeal cancer (RR 0.759, 95%CI: 0.581-0.993), breast (RR 0.885, 95%CI: 0.790-0.991) in case-control studies and stomach cancer in women (RR 0.633, 95%CI: 0.468-0.858). Our analysis indicates the potential benefits of flavan-3-ols in cancer prevention.

Does adherence to the World Cancer Research Fund/American Institute of Cancer Research cancer prevention guidelines reduce risk of colorectal cancer in the UK Women's Cohort Study?

Evidence on adherence to diet-related cancer prevention guidelines and associations with colorectal cancer (CRC) risk is limited and conflicting. The aim of this cohort analysis is to evaluate associations between adherence to the World Cancer Research Fund/American Institute of Cancer Research (WCRF/AICR) 2007 recommendations and incident CRC. The UK Women's Cohort Study comprises over 35 372 women who filled in a FFQ at baseline in 1995. They were followed up for CRC incidence for a median of 17·4 years, an individual score linking adherence to eight of the WCRF/AICR recommendations was constructed. Cox proportional hazards regression provided hazard ratios (HR) and 95 % CI for the estimation of CRC risk, adjusting for confounders. Following exclusions, 444 CRC cases were identified. In the multivariate-adjusted model, women within the second and third (highest) categories of the WRCF/AICR score had HR of 0·79 (95 % CI 0·62, 1·00) and 0·73 (95 % CI 0·48, 1·10), respectively, for CRC compared with those in the lowest, reference category. The overall linear trend across the categories was not significant (P=0·17). No significant associations were observed between the WCRF/AICR score and proximal colon, distal colon and rectal cancers separately. Of the individual score components, a BMI within the normal weight range was borderline significantly protective only for rectal cancer in the fully adjusted model. In view of the likely different causes of CRC subtypes, further research is needed to identify the optimal dietary patterns associated with reducing colon and rectal cancer risk, respectively.

Heterogeneous reciprocal graphical models

We develop novel hierarchical reciprocal graphical models to infer gene networks from heterogeneous data. In the case of data that can be naturally divided into known groups, we propose to connect graphs by introducing a hierarchical prior across group-specific graphs, including a correlation on edge strengths across graphs. Thresholding priors are applied to induce sparsity of the estimated networks. In the case of unknown groups, we cluster subjects into subpopulations and jointly estimate cluster-specific gene networks, again using similar hierarchical priors across clusters. We illustrate the proposed approach by simulation studies and three applications with multiplatform genomic data for multiple cancers.

Role of adjuvant chemotherapy in locally advanced rectal cancer with ypT0-3N0 after preoperative chemoradiation therapy and surgery

Background

We aimed to explore the clinical benefit of adjuvant chemotherapy (AC) with fluoropyrimidine in patients with ypT0-3N0 rectal cancer after preoperative chemoradiation therapy (CRT) followed by total mesorectal excision (TME).

Methods

Patients with ypT0-3N0 rectal cancer after preoperative CRT and TME were included using prospectively collected tumor registry cohort between January 2001 and December 2013. Patients were categorized into two groups according to the receipt of AC. Disease-free survival (DFS) and overall survival (OS) were compared between the adjuvant and observation groups. To control for potential confounding factors, we also calculated propensity scores and performed propensity score-matched analysis for DFS and OS.

Results

Of the 339 evaluated patients, 87 patients (25.7%) did not receive AC. There were no differences in DFS (hazard ratio [HR], 0.921; 95% confidence interval [CI], 0.562–1.507; P = 0.742) and OS (HR, 0.835; 95% CI, 0.423–1.648; P = 0.603) between the adjuvant and observation groups. After propensity score matching, DFS (HR, 1.129; 95% CI, 0.626–2.035; P = 0.688) and OS (HR, 1.200; 95% CI, 0.539–2.669; P = 0.655) did not differ between the adjuvant and observation groups. Advanced T stage and positive resection margin were independently associated with inferior DFS and OS on multivariate analysis.

Conclusions

AC did not improve DFS and OS for patients with ypT0-3N0 rectal cancer after preoperative CRT followed by TME in this cohort study. The confirmative role of AC in locally advanced rectal cancer should be evaluated in prospective randomized trials with a larger sample size.

Electronic supplementary material

The online version of this article (10.1186/s12885-017-3624-7) contains supplementary material, which is available to authorized users.

Colon cancer modulation by a diabetic environment: A single institutional experience

Background

Multiple observational studies suggest an increased risk of colon cancer in patients with diabetes mellitus (DM). This can theoretically be the result of an influence of the diabetic environment on carcinogenesis or the tumor biologic behavior.

Aim

To gain insight into the influence of a diabetic environment on colon cancer characteristics and outcomes.

Material and methods

Retrospective analysis of clinical records in an academic tertiary care hospital with detailed analysis of 81 diabetic patients diagnosed of colon cancer matched with 79 non-diabetic colon cancer patients. The impact of streptozotocin-induced diabetes on the growth of colon cancer xenografts was studied in mice.

Results

The incidence of DM in 1,137 patients with colorectal cancer was 16%. The diabetic colon cancer cases and non-diabetic colon cancer controls were well matched for demographic and clinical variables. The ECOG Scale Performance Status was higher (worse) in diabetics (ECOG ≥1, 29.1% of controls vs 46.9% of diabetics, p = 0.02), but no significant differences were observed in tumor grade, adjuvant therapy, tumor site, lymphovascular invasion, stage, recurrence, death or cancer-related death. Moreover, no differences in tumor variables were observed between patients treated or not with metformin. In the xenograft model, tumor growth and histopathological characteristics did not differ between diabetic and nondiabetic animals.

Conclusion

Our findings point towards a mild or negligible effect of the diabetes environment on colon cancer behavior, once cancer has already developed.

Molecular alterations in colorectal adenomas and intramucosal adenocarcinomas defined by high-density single-nucleotide polymorphism arrays

BACKGROUND

We examined colorectal adenomas and intramucosal adenocarcinomas (IMAs) to develop a genome-wide overview of copy number alterations (CNAs) during colorectal tumorigenesis.

METHODS

We analysed CNAs using a high-resolution SNP array of isolated tumour glands obtained from 55 colorectal adenomas (35 low-grade adenomas and 20 high-grade adenomas) and 30 IMAs. Next, we examined whether frequent CNAs differed between low-grade and high-grade adenomas or high-grade adenomas and IMAs. Finally, we investigated the total lengths of the CNAs in low-grade adenomas, high-grade adenomas, and IMAs.

RESULTS

Although no frequent CNAs were found in low-grade adenomas, the most frequent alterations of high-grade adenomas were gains of 7q11, 7q21 and 9p13 and loss of 5q14.3-35. High levels of gains were detected at 13q, 7q, 8p, 20q, 7p, 18p and 17p in IMAs. Although no frequent alteration differed between low-grade and high-grade adenomas, significant differences of gains at 13q, 17p and 18p were found between high-grade adenoma and IMAs. Although the total lengths of all CNAs (gains and losses), copy number gains, and losses of heterozygosity were significantly greater in high-grade adenomas than in low-grade adenomas, no significant differences in the lengths of CNAs were found between high-grade adenomas and IMAs.

CONCLUSIONS

Genomic alterations play an essential role in early colorectal carcinogenesis. CNAs in colorectal tumours provide new insights for evaluation of colorectal tumorigenesis.

Tumor LINE-1 Methylation Level in Association with Survival of Patients with Stage II Colon Cancer

Genome-wide DNA hypomethylation is associated with a worse prognosis in early-stage colorectal cancer. To measure genome-wide DNA methylation levels, long interspersed nucleotide element (LINE-1) repeats are used as a surrogate marker. Cohort studies on the clinical impact of genome-wide DNA methylation level in patients with only early-stage colon cancer, are currently lacking. This study aimed to investigate the prognostic value of LINE-1 methylation in a stage II colon cancer cohort (n = 164). Manual needle microdissection of tumor areas was performed on formalin-fixed paraffin-embedded tumor tissue sections followed by DNA extraction. Bisulfite converted DNA was used to assess tumor LINE-1 methylation level by qPCR. Patients with LINE-1 hypomethylated tumors had a significantly worse overall survival compared to patients with a higher level of LINE-1 tumor DNA methylation (HR 1.68, 95% CI 1.03–2.75; p = 0.04). This effect was more prominent in patients aged over 65 years (HR 2.00, 95% CI 1.13–3.52; p = 0.02), although the test for age interaction was not significant. No significant effect on recurrence-free survival was observed. Based on these results, tumor LINE-1 hypomethylation is associated with a worse overall survival in stage II colon cancer. Whether the origin of this causation is cancer-specific or age-related can be debated.

A stromal cell population in the large intestine identified by tissue factor expression that is lost during colorectal cancer progression

Colorectal cancer (CRC) is a major cause of morbidity and mortality, and the composition of the tumour stroma is a strong predictor of survival in this cancer type. Tissue factor (TF) functions as the trigger of haemostasis together with its ligand coagulation factor VII/VIIa, and TF expression has been found in tumour cells of colorectal tumours. However, TF expression in the CRC tumour stroma or its relationship to patient outcome has not yet been studied. To address this question we developed and validated a specific anti-TF antibody using standardised methods within the Human Protein Atlas project. We used this antibody to investigate TF expression in normal colorectal tissue and CRC using immunofluorescence and immunohistochemistry in two patient cohorts. TF was strongly expressed in a cell population immediately adjacent to the colorectal epithelium. These TF-positive cells were ACTA2-negative but weakly vimentin-positive, defining a specific population of pericryptal sheath cells. In colorectal tumours, TF-positive sheath cells were progressively lost after the adenoma-to-carcinoma transition, demonstrating downregulation of this source of TF in CRC. Furthermore, loss of sheath cell TF was significantly associated with poor overall and disease-specific survival in rectal but not colon cancers. In conclusion, we demonstrate that TF is a marker of a specific cell population in the large intestine, which is lost during CRC progression. Our results highlight the role of the tumour stroma in this cancer type and suggest TF to be a potential prognostic biomarker in rectal cancers through the identification of pericryptal sheath cells.

A genome-wide assessment of rare copy number variants in colorectal cancer

Colorectal cancer (CRC) is a complex disease with an estimated heritability of approximately 35%. However, known CRC-related common single nucleotide polymorphisms (SNPs) can only explain ~0.65% of the heritability. This “missing heritability” may be explained partially by rare copy number variants (CNVs). In this study, we performed a genome-wide scan using Illumina Human-Omni Express BeadChip, 694 sporadic CRC cases and 1641 controls were eventually included in our analysis after quality control. The global burden analysis revealed a 1.53-fold excess of rare CNVs in CRC cases compared with controls (P < 1 × 10⁻⁶), and the difference being more pronounced for genic rare CNVs and CNVs overlapped with coding regions (1.65-fold and 1.84-fold, respectively, both P < 1 × 10⁻⁶). Interestingly, both the cases in the lowest and middle tertile of age carried a higher burden of rare CNVs comparing to the highest tertile. Furthermore, 639 CNV-disrupted genes exclusive to CRC cases were found to be significantly enriched in gene ontology (GO) terms concerning nucleosome assembly and olfactory receptor activity. Our study was the first to evaluate the burden of rare CNVs in sporadic CRC and suggested that rare CNVs contributed to the missing heritability of CRC.

Lysyl Oxidase Gene G473A Polymorphism and Cigarette Smoking in Association with a High Risk of Lung and Colorectal Cancers in a North Chinese Population

The relationship among the lysyl oxidase (LOX) G473A single nucleotide polymorphism (SNP), cigarette smoking and lung, colorectal, colon and rectum cancer susceptibility was studied in 200 cases of lung cancer, 335 cases of colorectal cancer including 130 cases of colon cancer and 205 cases of rectum cancer, and 335 healthy people in Tangshan, China. Peripheral blood DNA samples were collected, DNA sequencing and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) performed, followed by multivariate logistic regression analysis. In comparison to LOX473GG genotype carriers, individuals with LOX473AA exhibited a higher susceptibility to lung, colon-rectum, colon, and rectum cancers with OR values amounting to 3.84-, 2.74-, 2.75-, and 2.74-fold of the control, respectively. In the LOX 473AA-positive population, females were more susceptible than males to carcinogenesis with OR values (female vs. male): 5.25 vs. 3.23, 2.29 vs. 1.51, 2.27 vs. 1.45, and 2.25 vs. 1.53, respectively, for lung, colon-rectum combined, colon, and rectum cancers. LOX G473A polymorphism apparently elevated human sensitivity to cigarette smoking carcinogens for eliciting cancers in the lung and colon only. Thus, LOX G473A polymorphism positively correlates with carcinogenesis and it may be used as an ideal intrinsic biomarker for prediction or diagnosis of carcinogenesis in humans.

TNFRSF10C copy number variation is associated with metastatic colorectal cancer

BACKGROUND

Genetic markers for distant metastatic disease in patients with colorectal cancer (CRC) are not well defined. Identification of genetic alterations associated with metastatic CRC could help to guide systemic and local treatment strategies. We evaluated the association of tumor necrosis factor receptor superfamily member 10C (TNFRSF10C) copy number variation (CNV) with distant metastatic disease in patients with CRC using The Cancer Genome Atlas (TCGA).

METHODS

Genetic sequencing data and clinical characteristics were obtained from TCGA for all available patients with CRC. There were 515 CRC patient samples with CNV and clinical outcome data, including a subset of 144 rectal adenocarcinoma patient samples. Using the TCGA CRC dataset, CNV of TNFRSF10C was evaluated for association with distant metastatic disease (M1 vs. M0). Multivariate logistic regression analysis with odds ratio (OR) using a 95% confidence interval (CI) was performed adjusting for age, T stage, N stage, adjuvant chemotherapy, gender, microsatellite instability (MSI), location, and surgical margin status.

RESULTS

TNFRSF10C CNV in patients with CRC was associated with distant metastatic disease [OR 4.81 (95% CI, 2.13-10.85) P<0.001] and positive lymph nodes [OR 18.83 (95% CI, 8.42-42.09)]; P<0.001) but not MSI (OR P=0.799). On multivariate analysis, after adjusting for pathologic T stage, N stage, adjuvant chemotherapy, gender, and MSI, TNFRSF10C CNV remained significantly associated with distant metastatic disease (OR P=0.018). Subset analysis revealed that TNFRSF10C CNV was also significantly associated with distant metastatic disease in patients with rectal adenocarcinoma (OR P=0.016).

CONCLUSIONS

TNFRSF10C CNV in patients with CRC is associated with distant metastatic disease. With further validation, such genetic profiles could be used clinically to support optimal systemic treatment strategies versus more aggressive local therapies in patients with CRC, including radiation therapy for rectal adenocarcinoma.

Differences between colon and rectal cancer in complications, short-term survival and recurrences

PURPOSE

Many apparent differences exist in aetiology, genetics, anatomy and treatment response between colon cancer (CC) and rectal cancer (RC). This study examines the differences in patient characteristics, prevalence of complications and their effect on short-term survival, long-term survival and the rate of recurrence between RC and CC.

METHODS

For all stage II-III CC and RC patients who underwent resection with curative intent (2006-2008) in five hospitals in the Netherlands, occurrence of complications, crude survival, relative survival and recurrence rates were compared.

RESULTS

A total of 767 CC and 272 RC patients underwent resection. Significant differences were found for age, gender, emergency surgery, T-stage and grade. CC patients experienced fewer complications compared to RC (p = 0.019), but CC patients had worse short-term mortality rates (1.5 versus 6.7 % for 30-day mortality, p = 0.001 and 5.2 versus 9.5 % for 90-day mortality, p = 0.032). The adjusted HR (overall survival) for CC patients with complications was 1.57 (1.23-2.01; p < 0.001) as compared to patients without complications; for RC, the HR was 1.79 (1.12-2.87; p = 0.015). Relative survival analyses showed high excess mortality in the first months after surgery and a sustained, prolonged negative effect on both CC and RC. Complications were associated with a higher recurrence rate for both CC and RC; adjusted analyses showed a trend towards a significant association.

CONCLUSION

Large differences exist in patient characteristics and clinical outcomes between CC and RC. CC patients have a significantly higher short-term mortality compared to RC patients due to a more severe effect of complications.

The Association between Glyceraldehyde-Derived Advanced Glycation End-Products and Colorectal Cancer Risk

BACKGROUND

A large proportion of colorectal cancers are thought to be associated with unhealthy dietary and lifestyle exposures, particularly energy excess, obesity, hyperinsulinemia, and hyperglycemia. It has been suggested that these processes stimulate the production of toxic reactive carbonyls from sugars such as glyceraldehyde. Glyceraldehyde contributes to the production of a group of compounds known as glyceraldehyde-derived advanced glycation end-products (glycer-AGEs), which may promote colorectal cancer through their proinflammatory and pro-oxidative properties. The objective of this study nested within a prospective cohort was to explore the association of circulating glycer-AGEs with risk of colorectal cancer.

METHODS

A total of 1,055 colorectal cancer cases (colon n = 659; rectal n = 396) were matchced (1:1) to control subjects. Circulating glycer-AGEs were measured by a competitive ELISA. Multivariable conditional logistic regression models were used to calculate ORs and 95% confidence intervals (95% CI), adjusting for potential confounding factors, including smoking, alcohol, physical activity, body mass index, and diabetes status.

RESULTS

Elevated glycer-AGEs levels were not associated with colorectal cancer risk (highest vs. lowest quartile, 1.10; 95% CI, 0.82-1.49). Subgroup analyses showed possible divergence by anatomical subsites (OR for colon cancer, 0.83; 95% CI, 0.57-1.22; OR for rectal cancer, 1.90; 95% CI, 1.14-3.19; Pheterogeneity = 0.14).

CONCLUSIONS

In this prospective study, circulating glycer-AGEs were not associated with risk of colon cancer, but showed a positive association with the risk of rectal cancer.

IMPACT

Further research is needed to clarify the role of toxic products of carbohydrate metabolism and energy excess in colorectal cancer development.

Elevated CA19-9 as the Most Significant Prognostic Factor in Locally Advanced Rectal Cancer Following Neoadjuvant Chemoradiotherapy

It remains controversial regarding the prognostic significance of carbohydrate antigen 19-9 (CA19-9) for locally advanced rectal cancer (LARC) (T3-4/N+) patients with neoadjuvant chemoradiotherapy (neo-CRT). And it is unknown whether CA19-9 can identify patients who may benefit from adjuvant chemotherapy.Overall, 303 LARC patients with neo-CRT between 2004 and 2010 were recruited. Overall survival (OS), disease-free survival (DFS), distant metastasis-free survival (DMFS), and local recurrence-free survival across pretreatment CA19-9 were estimated by Kaplan-Meier method and Cox regression model.In univariate analysis, elevated CA19-9 (>35 U/mL) was significantly correlated with poor OS (P = 0.003), DFS (P = 0.001), and DMFS (P = 0.039). Adjusting for the known covariates, CA19-9 was significantly associated with OS (HR = 1.86, 95% CI 1.03-3.34, P = 0.039) and DFS (HR = 1.74, 95% CI 1.08-2.80, P = 0.024). In the elevated CA19-9 subgroup, patients with adjuvant chemotherapy got much better OS (P < 0.001) and DFS (P = 0.016) than those without. In consideration of both CA19-9 and carcinoembryonic antigen (CEA), we found that patients with both elevated CA19-9 and CEA (>5 ng/mL) got the worst OS (P = 0.021) and DFS (P = 0.006), and significantly benefited from adjuvant chemotherapy in OS (P < 0.001) and DFS (P = 0.026).Pretreatment CA19-9 level is a significant prognostic indicator in patients with LARC following neo-CRT. The addition of CA19-9 to CEA is valuable to discriminate the appropriate patients for adjuvant chemotherapy.

Clinical significance of differential expression of interleukin 8 mRNA in left-sided and right-sided colon cancer

AIM: To investigate the differential expression of interleukin 8 (IL-8) between left-sided and right-sided colon cancer and to analyze its clinical significance.

METHODS: Eighty patients who received radical resection for stage II or III colon cancer were involved, including 40 patients with left-sided colon cancer (LSCC) and 40 with right-sided colon cancer (RSCC). Paired cancer and normal colon mucosal specimens were collected from each patient. The gene expression of IL-8 was detected by real-time quantitative PCR. Subsequently, the relationship between IL-8 expression and clinicopathological variables as well as prognosis was analyzed.

RESULTS: The mRNA expression of IL-8 in colon cancer was significantly higher than that in normal colon mucosa (P < 0.01). IL-8 expression was significantly higher in RSCC than in LSCC (P = 0.004). High IL-8 expression was closely related with RSCC (65% vs 35%, P = 0.007), bigger tumor size (5.2 cm vs 4.1 cm, P = 0.014) and tumor infiltrating lymphocytes (27.5% vs 10%,P = 0.045). In patients with LSCC, the survival of patients with high IL-8 expression was significantly shorter than that in patients with low IL-8 expression (37.0 mo vs 59.2 mo, P = 0.006). However, among patients with RSCC, patients with high IL-8 expression tended to have a better prognosis than patients with low expression (63.8 mo vs 54.5 mo, P = 0.151). Multivariate analysis demonstrated that T4 infiltration (RR = 6.514, 95%CI: 1.209-35.102, P = 0.029) and lymphatic/vascular invasion (RR = 6.272, 95%CI: 1.352-29.092, P = 0.019) were independent prognostic factors of RSCC, and high IL-8 expression (RR = 3.279, 95%CI: 0.973-11.051, P = 0.045), T4 infiltration (RR = 4.546, 95%CI: 1.335-15.481, P = 0.015), lymph node metastasis (RR = 5.918, 95%CI: 1.439-24.334, P = 0.014) and lymphatic/vascular invasion (RR = 3.663, 95%CI: 1.089-12.320, P = 0.036) were independent prognostic factors of LSCC.

CONCLUSION: The gene expression of IL-8 is significantly different between RSCC and LSCC. High IL-8 expression has a different prognostic impact on RSCC and LSCC. RSCC and LSCC are two potentially heterogeneous groups with differences in molecular and carcinogenic mechanisms.

Prognostic factors for overall survival in metastatic colorectal cancer using a stop-and-go FLIRI-based treatment strategy

PURPOSE

To determine overall survival and baseline prognostic variables in a cohort of patients with metastatic colorectal cancer receiving a FLIRI-based stop-and-go treatment strategy.

METHODS

Clinical information was collected from patient files in consecutive patients treated with palliative combination chemotherapy using a stop-and-go strategy from September 2007 until June 2011. The primary outcome was overall survival. Cox regression analysis was used to examine the effect of prognostic variables on survival. Baseline variables were performance status, primary tumor site, status of primary tumor (resected or unresected), synchronous metastases, >1 metastatic site, liver-only metastases, alkaline phosphatase (>300 U/l), lactate dehydrogenase (>300 U/l), platelets (>400 × 10(9)/l), and leucocytes (>10 × 10(9)/l).

RESULTS

We included 314 patients (median age 64.5 (57-70) years). Median overall survival was 20.9 (95 % confidence interval (CI), 19.1-223.4) months with a median follow-up of 21.3 months (interquartile range (IQR) 13-34.8). Independent prognostic markers of decreased survival were PS 1 and 2 vs. 0 hazard ratio (HR) 1.47 (95 % CI 1.14-1.91, p = 0.003) and HR 2.06 (95 % CI 1.19-3.56, p = 0.01), colon as the primary tumor site HR 1.43 (95 % CI 1.09-1.88, p = 0.009), unresected primary tumor HR 2.22 (95 % CI 1.61-3.07, p < 0.001), and elevated leucocytes (>10 × 10(9)/l) HR 1.53 (95 % CI 1.12-2.09, p = 0.007).

CONCLUSIONS

Overall survival in metastatic colorectal cancer using a FLIRI-based stop-and-go strategy in an unselected consecutive cohort proved comparable to RCTs from the same period. Baseline prognostic markers of poorer prognosis were PS 1 or 2, colon as primary tumor site, unresected primary tumor, and leucocytes >10 × 10(9)/l. These variables are all easy accessible in daily clinical practice.

Genetic mutations in human rectal cancers detected by targeted sequencing

Colorectal cancer (CRC) is widespread with significant mortality. Both inherited and sporadic mutations in various signaling pathways influence the development and progression of the cancer. Identifying genetic mutations in CRC is important for optimal patient treatment and many approaches currently exist to uncover these mutations, including next-generation sequencing (NGS) and commercially available kits. In the present study, we used a semiconductor-based targeted DNA-sequencing approach to sequence and identify genetic mutations in 91 human rectal cancer samples. Analysis revealed frequent mutations in KRAS (58.2%), TP53 (28.6%), APC (16.5%), FBXW7 (9.9%) and PIK3CA (9.9%), and additional mutations in BRAF, CTNNB1, ERBB2 and SMAD4 were also detected at lesser frequencies. Thirty-eight samples (41.8%) also contained two or more mutations, with common combination mutations occurring between KRAS and TP53 (42.1%), and KRAS and APC (31.6%). DNA sequencing for individual cancers is of clinical importance for targeted drug therapy and the advantages of such targeted gene sequencing over other NGS platforms or commercially available kits in sensitivity, cost and time effectiveness may aid clinicians in treating CRC patients in the near future.

A clinicopathological analysis of KISS1 and KISS1R expression in colorectal cancer

Kisspeptins, the products of the KISS1 gene have tumor suppressing and antimetastatic properties. We aimed to study KISS1 and KISS1R expression in colorectal cancer. We analyzed KISS1 and KISS1R expression using immunohistochemistry and image analysis in normal and malignant tissue samples from 111 patients with colorectal adenocarcinoma. KISS1 expression was much higher in the normal than in the malignant colonic mucosa. Regarding malignant tissues, KISS1 levels were higher in larger tumors, in stage III and IV cancers, in cancers with lymph node metastasis and in tumors located in the distal part of the large intestine. Patients with greater KISS1 levels had worse prognosis. No KISS1R expression was detected in normal or malignant tissues or in liver metastases. KISS1 expression is reduced during the malignant transformation of the colonic mucosa. However, larger and advanced colorectal cancers express more KISS1, without reaching the former normal levels, and increased KISS1 levels are associated with worse prognosis. Finally, neither the normal nor the malignant colonic epithelial cells produce KISS1R.

Adjuvant chemotherapy after preoperative (chemo)radiotherapy and surgery for patients with rectal cancer: a systematic review and meta-analysis of individual patient data

BACKGROUND

The role of adjuvant chemotherapy for patients with rectal cancer after preoperative (chemo)radiotherapy and surgery is uncertain. We did a meta-analysis of individual patient data to compare adjuvant chemotherapy with observation for patients with rectal cancer.

METHODS

We searched PubMed, Medline, Embase, Web of Science, the Cochrane Library, CENTRAL, and conference abstracts to identify European randomised, controlled, phase 3 trials comparing observation with adjuvant chemotherapy after preoperative (chemo)radiotherapy and surgery for patients with non-metastatic rectal cancer. The primary endpoint of interest was overall survival.

FINDINGS

We analysed data from four eligible trials, including data from 1196 patients with (y)pTNM stage II or III disease, who had an R0 resection, had a low anterior resection or an abdominoperineal resection, and had a tumour located within 15 cm of the anal verge. We found no significant differences in overall survival between patients who received adjuvant chemotherapy and those who underwent observation (hazard ratio [HR] 0.97, 95% CI 0.81-1.17; p=0.775); there were no significant differences in overall survival in subgroup analyses. Overall, adjuvant chemotherapy did not significantly improve disease-free survival (HR 0.91, 95% CI 0.77-1.07; p=0.230) or distant recurrences (0.94, 0.78-1.14; p=0.523) compared with observation. However, in subgroup analyses, patients with a tumour 10-15 cm from the anal verge had improved disease-free survival (0.59, 0.40-0.85; p=0.005, p(interaction)=0.107) and fewer distant recurrences (0.61, 0.40-0.94; p=0.025, p(interaction)=0.126) when treated with adjuvant chemotherapy compared with patients undergoing observation.

INTERPRETATION

Overall, adjuvant fluorouracil-based chemotherapy did not improve overall survival, disease-free survival, or distant recurrences. However, adjuvant chemotherapy might benefit patients with a tumour 10-15 cm from the anal verge in terms of disease-free survival and distant recurrence. Further studies of preoperative and postoperative treatment for this subgroup of patients are warranted.

FUNDING

None.

Immunohistochemical detection of p53 expression in patients with preoperative chemoradiation for rectal cancer: association with prognosis

PURPOSE

The expression of p53 in patients with rectal cancer who underwent preoperative chemoradiation and and its potential prognostic significance were evaluated.

MATERIALS AND METHODS

p53 expression was examined using immunohistochemistry in pathologic specimens from 210 rectal cancer patients with preoperative chemoradiotherapy and radical surgery. All patients were classified into two groups according to the p53 expression: low p53 (<50% nuclear staining) and high p53 (≥50%) groups.

RESULTS

p53 expression was significantly associated with tumor location from the anal verge (p=0.036). In univariate analysis, p53 expression was not associated with disease-free survival (p=0.118) or local recurrence-free survival (p=0.089). Multivariate analysis showed that tumor distance from the anal verge (p=0.006), ypN category (p=0.011), and perineural invasion (p=0.048) were independent predictors of disease-free survival; tumor distance from the anal verge was the only independent predictor of local recurrence-free survival. When the p53 groups were subdivided according to ypTNM category, disease-free survival differed significantly in patients with ypN+ disease (p=0.027) only.

CONCLUSION

Expression of p53 in pathologic specimens as measured by immunohistochemical methods may have a significant prognostic impact on survival in patients with ypN+ rectal cancer with preoperative chemoradiotherapy. However, it was not an independent predictor of recurrence or survival.

Adjuvant chemotherapy for rectal cancer patients treated with preoperative (chemo)radiotherapy and total mesorectal excision: a Dutch Colorectal Cancer Group (DCCG) randomized phase III trial

BACKGROUND

The discussion on the role of adjuvant chemotherapy for rectal cancer patients treated according to current guidelines is still ongoing. A multicentre, randomized phase III trial, PROCTOR-SCRIPT, was conducted to compare adjuvant chemotherapy with observation for rectal cancer patients treated with preoperative (chemo)radiotherapy and total mesorectal excision (TME).

PATIENTS AND METHODS

The PROCTOR-SCRIPT trial recruited patients from 52 hospitals. Patients with histologically proven stage II or III rectal adenocarcinoma were randomly assigned (1:1) to observation or adjuvant chemotherapy after preoperative (chemo)radiotherapy and TME. Radiotherapy consisted of 5 × 5 Gy. Chemoradiotherapy consisted of 25 × 1.8-2 Gy combined with 5-FU-based chemotherapy. Adjuvant chemotherapy consisted of 5-FU/LV (PROCTOR) or eight courses capecitabine (SCRIPT). Randomization was based on permuted blocks of six, stratified according to centre, residual tumour, time between last irradiation and surgery, and preoperative treatment. The primary end point was overall survival.

RESULTS

Of 470 enrolled patients, 437 were eligible. The trial closed prematurely because of slow patient accrual. Patients were randomly assigned to observation (n = 221) or adjuvant chemotherapy (n = 216). After a median follow-up of 5.0 years, 5-year overall survival was 79.2% in the observation group and 80.4% in the chemotherapy group [hazard ratio (HR) 0.93, 95% confidence interval (CI) 0.62-1.39; P = 0.73]. The HR for disease-free survival was 0.80 (95% CI 0.60-1.07; P = 0.13). Five-year cumulative incidence for locoregional recurrences was 7.8% in both groups. Five-year cumulative incidence for distant recurrences was 38.5% and 34.7%, respectively (P = 0.39).

CONCLUSION

The PROCTOR-SCRIPT trial could not demonstrate a significant benefit of adjuvant chemotherapy with fluoropyrimidine monotherapy after preoperative (chemo)radiotherapy and TME on overall survival, disease-free survival, and recurrence rate. However, this trial did not complete planned accrual.

REGISTRATION NUMBER

Dutch Colorectal Cancer group, CKTO 2003-16, ISRCTN36266738.

Colon cancer surgery following emergency presentation: effects on admission and stage-adjusted outcomes

BACKGROUND

Emergency presentation with colon cancer is intuitively related to advanced disease. We measured its effect on outcomes of surgically treated colon cancer.

METHODS

A retrospective cohort of 1,071 surgical colon cancer patients (2004 to 2011), with 102 emergency cases requiring surgery within the index admission, was analyzed.

RESULTS

Emergency patients required longer surgeries (median 141 vs 124 minutes; P = .04), longer median admissions (8% vs 5%; P < .001), more readmissions (12.7% vs 7.1%; P = .040), and perioperative mortality (7.8% vs .8%; P < .001). Surgical pathology displayed higher rates of node-positive disease (56.6% vs 38.6%; P < .001), extramural vascular invasion (39.6% vs 29.1%; P = .021), and metastatic disease (19.6% vs 8%; P < .001). Consequently, adjusting for staging, emergency presentations had considerably higher mortality (odds ratio = 2.07; P = .003) and shorter disease-free survival (hazard ratio = 1.39; P = .042).

CONCLUSIONS

Emergency presentation is a stage-independent poor prognostic factor associated with aggressive tumor biology, resulting in longer surgeries and admissions, frequent readmissions, worsening outcomes, and increasing healthcare costs.

Epigenetic inactivation of the novel candidate tumor suppressor gene ITIH5 in colon cancer predicts unfavorable overall survival in the CpG island methylator phenotype

Inter-α-trypsin inhibitor heavy chain 5 (ITIH5) is supposed to be involved in extracellular matrix stability and thus may play a key role in the inhibition of tumor progression. The current study is the first to analyze in depth ITIH5 expression as well as its potential clinical and functional impact in colon cancer. Based on 30 tumor and 30 adjacent normal tissues we examined ITIH5 mRNA expression and promoter methylation, whose significance was further validated by independent data sets from The Cancer Genome Atlas (TCGA) platform. In addition, ITIH5 protein expression was evaluated using immunohistochemistry. ITIH5 mRNA expression loss was significantly associated (P<0.001) with hypermethylation of the ITIH5 promoter in primary colon tumors. In addition, treatment of tumor cell lines with demethylating (DAC) and histone acetylating (TSA) agents induced ITIH5 expression. In line, independent TCGA data revealed a significant expression loss of ITIH5, particularly in the MSI-high and CIMP-positive phenotype concordant with an increased ITIH5 hypermethylation in CIMP-positive colon tumors (P<0.001). In proximal, i.e., right-sided tumors, abundant ITIH5 expression was associated with longer overall survival (OS, P = 0.049) and the CIMP-positive (P = 0.032) subgroup. Functionally, ITIH5 re-expression mediated a reduced proliferation in HCT116 and CaCo2 cells. In conclusion, our results indicate that ITIH5 is a novel putative tumor suppressor gene in colon cancer with a potential impact in the CIMP-related pathway. ITIH5 may serve as a novel epigenetic-based diagnostic biomarker with further clinical impact for risk stratification of CIMP-positive colon cancer patients.

KRAS mutation profile differences between rectosigmoid localized adenocarcinomas and colon adenocarcinomas

BACKGROUND

Colorectal cancer has a heterogeneous nature that is influenced by the tumour site. Many improvements have been made in identifying and characterizing the genetic alterations between colon and rectal cancers. However, there is not enough information about KRAS mutational differences between rectosigmoid and colon cancers arising elsewhere in the large bowel. The aim of this study was to determine the differences in the frequency of KRAS genetic alterations between rectosigmoid cancers and colon cancers.

METHODS

Eighty-four patients diagnosed with colorectal cancer were included in this study. Genomic DNA was extracted from formalin-fixed paraffin-embedded tumour tissue sections. KRAS mutation analysis which was designed to detect the seven most common KRAS gene mutations (Gly12Ala, Gly12Asp, Gly12Arg, Gly12Cys, Gly12Ser, Gly12Val and Gly13Asp) was performed. Chi-square test was used to test the association between mutation status and other variables.

RESULTS

This study represents the first KRAS mutational results from Turkish rectosigmoid cancer patients. The KRAS mutation frequency of rectosigmoid tumours is higher (34.3%, 12/35) than that of colon-localized tumours (30.6%, 15/49). However, there is no significant correlation between the KRAS mutation status and tumour location (rectosigmoid and colon).

CONCLUSIONS

KRAS mutation analysis has a predictive and prognostic value in identifying tumours that may be resistant to treatment. Our study shows that differences in the biological behaviour of rectosigmoid and colon cancers should be considered. This finding highlights the importance of personalized cancer management, which could be assisted by cancer genotyping tools.

Novel diet-related mouse model of colon cancer parallels human colon cancer

AIM: To investigate the close parallels between our novel diet-related mouse model of colon cancer and human colon cancer.

METHODS: Twenty-two wild-type female mice (ages 6-8 wk) were fed the standard control diet (AIN-93G) and an additional 22 female mice (ages 6-8 wk) were fed the control diet supplemented with 0.2% deoxycholic acid [diet + deoxycholic acid (DOC)] for 10 mo. Tumors occurred in the colons of mice fed diet + DOC and showed progression to colon cancer [adenocarcinoma (AC)]. This progression is through the stages of tubular adenoma (TA), TA with high grade dysplasia or adenoma with sessile serrated morphology, intramucosal AC, AC stage T1, and AC stage T2. The mouse tumors were compared to human tumors at the same stages by histopathological analysis. Sections of the small and large intestines of mice and humans were evaluated for glandular architecture, cellular and nuclear morphology including cellular orientation, cellular and nuclear atypia, pleomorphism, mitotic activity, frequency of goblet cells, crypt architecture, ulceration, penetration of crypts through the muscularis mucosa and presence of malignant crypts in the muscularis propria. In addition, preserved colonic tissues from genetically similar male mice, obtained from a prior experiment, were analyzed by immunohistochemistry. The male mice had been fed the control diet or diet + DOC. Four molecular markers were evaluated: 8-OH-dG, DNA repair protein ERCC1, autophagy protein beclin-1 and the nuclear location of beta-catenin in the stem cell region of crypts. Also, male mice fed diet + DOC plus 0.007% chlorogenic acid (diet + DOC + CGA) were evaluated for ERCC1, beclin-1 and nuclear location of beta-catenin.

RESULTS: Humans with high levels of diet-related DOC in their colons are at a substantially increased risk of developing colon cancer. The mice fed diet + DOC had levels of DOC in their colons comparable to that of humans on a high fat diet. The 22 mice without added DOC in their diet had no colonic tumors while 20 of the 22 mice (91%) fed diet + DOC developed colonic tumors. Furthermore, the tumors in 10 of these mice (45% of mice) included an adenocarcinoma. All mice were free of cancers of the small intestine. Histopathologically, the colonic tumor types in the mice were virtually identical to those in humans. In humans, characteristic aberrant changes in molecular markers can be detected both in field defects surrounding cancers (from which cancers arise) and within cancers. In the colonic tissues of mice fed diet + DOC similar changes in biomarkers appeared to occur. Thus, 8-OH-dG was increased, DNA repair protein ERCC1 was decreased, autophagy protein beclin-1 was increased and, in the stem cell region at the base of crypts there was substantial nuclear localization of beta-catenin as well as increased cytoplasmic beta-catenin. However, in mice fed diet + DOC + CGA (with reduced frequency of cancer) and evaluated for ERCC1, beclin-1, and beta-catenin in the stem cell region of crypts, mouse tissue showed amelioration of the aberrancies, suggesting that chlorogenic acid is protective at the molecular level against colon cancer. This is the first diet-related model of colon cancer that closely parallels human progression to colon cancer, both at the histomorphological level as well as in its molecular profile.

CONCLUSION: The diet-related mouse model of colon cancer parallels progression to colon cancer in humans, and should be uniquely useful in model studies of prevention and therapeutics.