Association of TP53 mutational status and gender with survival after adjuvant treatment for stage III colon cancer: results of CALGB 89803

Evaluating the utility of ZNF331 promoter methylation as a prognostic and predictive marker in stage III colon cancer: results from CALGB 89803 (Alliance)

While epigenomic alterations are common in colorectal cancers (CRC), few epigenomic biomarkers that risk-stratify patients have been identified. We thus sought to determine the potential of ZNF331 promoter hypermethylation (mZNF331) as a prognostic and predictive marker in colon cancer. We examined the association of mZNF331 with clinicopathologic features, relapse, survival, and treatment efficacy in patients with stage III colon cancer treated within a randomized adjuvant chemotherapy trial (CALGB/Alliance89803). Residual tumour tissue was available for genomic DNA extraction and methylation analysis for 385 patients. ZNF331 promoter methylation status was determined by bisulphite conversion and fluorescence-based real-time polymerase chain reaction. Kaplan-Meier estimator and Cox proportional hazard models were used to assess the prognostic and predictive role of mZNF331 in this well-annotated dataset, adjusting for clinicopathologic features and standard molecular markers. mZNF331 was observed in 267/385 (69.4%) evaluable cases. Histopathologic features were largely similar between patients with mZNF331 compared to unmethylated ZNF331 (unmZNFF31). There was no significant difference in disease-free or overall survival between patients with mZNF331 versus unmZNF331 colon cancers, even when adjusting for clinicopathologic features and molecular marker status. Similarly, there was no difference in disease-free or overall survival across treatment arms when stratified by ZNF331 methylation status. While ZNF331 promoter hypermethylation is frequently observed in CRC, our current study of a small subset of patients with stage III colon cancer suggests limited applicability as a prognostic marker. Larger studies may provide more insight and clarity into the applicability of mZNF331 as a prognostic and predictive marker.

Sex Difference of Colon Adenoma Pathway and Colorectal Carcinogenesis

Colorectal cancer (CRC) is one of the most common causes of cancer morbidity in both sexes but shows sex differences. First, sex-specific differences in tumor recurrence and survival rates have been reported. For example, the development of CRC is found about 1.5 times higher and 4-8 years earlier in males compared to females, suggesting the protective role of estrogen in the disease. Furthermore, female patients have a higher risk of developing right-sided (proximal) colon cancer than male patients, which is known to have more aggressive clinical character compared to left-sided (distal) colon cancer. That is, left and right CRCs show differences in carcinogenic mechanism, that the chromosomal instability pathway is more common in left colon cancer while the microsatellite instability and serrated pathways are more common in right colon cancer. It is thought that there are sex-based differences on the background of carcinogenesis of CRC. Sex differences of CRC have two aspects, sexual dimorphism (biological differences in hormones and genes) and gender differences (non-biological differences in societal attitudes and behavior). Recently, sex difference of colon adenoma pathway and sexual dimorphism in the biology of gene and protein expression, and in endocrine cellular signaling in the CRC carcinogenesis have been accumulated. In addition, behavioral patterns can lead to differences in exposure to risk factors such as drinking or smoking, diet and physical activity. Therefore, understanding sex/gender-related biological and sociocultural differences in CRC risk will help in providing strategies for screening, treatment and prevention protocols to reduce the mortality and improve the quality of life. In this review, sex/gender differences in colon adenoma pathway and various aspects such as clinicopathological, biological, molecular, and socio-cultural aspects of CRC were described.

Correlation Analysis of the TP53 Mutation With Clinical Characteristics in the Prognosis of Non-Small Cell Lung Cancer

Background

Non-small cell lung cancer (NSCLC) with TP53 mutations has a worse prognosis. It was generally more resistant to chemotherapy and radiation. Our aim was to investigate the correlation between the TP53 co-mutated gene and clinical features, and prognostic value in patients with NSCLC.

Methods

Seventy-three patients with a diagnosis of NSCLC at our hospital were recruited. They were divided into the TP53 mutation status (minor) (TP53 MU) and TP53 wild-type (major) (TP53 WT) groups according to their clinical characteristics after their mutation data and clinical information were collected. Serum markers were compared between groups using Mann-Whitney U test. Other clinical factors were compared between groups using χ2 test and Fisher exact test. The log-rank test was used to compare survival curves.

Results

Of the 73 patients with NSCLC, 37 (50.68%) were found to carry TP53 mutation. TP53 MU and TP53 WT groups (n = 36) showed a significant difference in the number of smokers, incidence of squamous cell carcinoma, EGFR mutation, and number of advanced patients (P < .05), while gender, age, lymph node metastasis, and KRAS mutation did not differ significantly between the 2 groups. The survival curves in the TP53/KRAS and the TP53/EGFR co-mutation groups suggest that patients with NSCLC may have a shorter progression-free survival (PFS) if they carry one of the 2 types of co-mutation.

Conclusions

TP53 gene mutations are more common in patients with NSCLC and squamous cell carcinoma. New predictive markers for NSCLC prognosis may be TP53/KRAS and TP53/EGFR co-mutations.

Development of fatty acid metabolism-related models in lung adenocarcinomaA Review

BACKGROUD

Lung adenocarcinoma (LUAD) is 1 of the common malignancy with a poor prognosis.

MATERIALS AND METHODS

Based on bioinformatics, the fatty acid metabolism model of LUAD was developed. We downloaded LUAD transcriptome data from the cancer genome atlas and gene expression omnibus databases. We used bioinformatics methods to construct a fatty acid metabolism-related predictive risk model to predict the prognosis of LUAD. We further explored the relationship between prognostic models and survival and immunity.

RESULTS

We identified 17 prognosis-related fatty acid-associated genes and constructed prognostic models. In the the cancer genome atlas cohort, the prognosis was worse in the high-risk score group compared to the low-risk score group. The ROC curve confirmed its accuracy. Subsequently, we used the gene expression omnibus database to confirm the above findings. There were differences in immune infiltrating cell abundance and immune function between the high-risk score group and low-risk score group. The immune dysfunction and exclusion (TIDE) based algorithm showed that the low-risk score group was more suitable for the immune treatment.

CONCLUSION

Fatty acid metabolic patterns can deepen the understanding of the immune microenvironment of LUAD and be used to guide the formulation of immunotherapy protocols.

Integrating machine learning and single-cell trajectories to analyze T-cell exhaustion to predict prognosis and immunotherapy in colon cancer patients

Introduction

The incidence of colon adenocarcinoma (COAD) has recently increased, and patients with advanced COAD have a poor prognosis due to treatment resistance. Combining conventional treatment with targeted therapy and immunotherapy has shown unexpectedly positive results in improving the prognosis of patients with COAD. More study is needed to determine the prognosis for patients with COAD and establish the appropriate course of treatment.

Methods

This study aimed to explore the trajectory of T-cell exhaustion in COAD to predict the overall survival and treatment outcome of COAD patients. Clinical data were derived from the TCGA-COAD cohort through "UCSC", as well as the whole genome data. Prognostic genes driving T-cell trajectory differentiation were identified on the basis of single-cell trajectories and univariate Cox regression. Subsequently, T-cell exhaustion score (TES) was created by iterative LASSO regression. The potential biological logic associated with TES was explored through functional analysis, immune microenvironment assessment, immunotherapy response prediction, and in vitro experiments.

Results

Data showed that patients with significant TES had fewer favorable outcomes. Expression, proliferation, and invasion of COAD cells treated with TXK siRNA were also examined by cellular experiments. Both univariate and multivariate Cox regression indicated that TES was an independent prognostic factor in patients with COAD; in addition, subgroup analysis supported this finding. Functional assay revealed that immune response and cytotoxicity pathways are associated with TES, as the subgroup with low TES has an active immune microenvironment. Furthermore, patients with low TES responded better to chemotherapy and immunotherapy.

Conclusion

In this study, we systematically explored the T-cell exhaustion trajectory in COAD and developed a TES model to assess prognosis and provide guidelines for the treatment decision. This discovery gave rise to a fresh concept for novel therapeutic procedures for the clinical treatment of COAD.

Evaluation of methylated DCR1 as a biomarker for response to adjuvant irinotecan-based therapy in stage III colon cancer: cancer and leukaemia Group B 89803 (Alliance)

Aberrantly methylated genes contribute to the landscape of epigenetic alterations in colorectal adenocarcinoma. The global CpG Island methylator phenotype (CIMP) and individually methylated genes are potential prognostic/predictive biomarkers. Research suggests an association between methylated DCR1 (mDCR1) and lack of benefit with irinotecan (IFL) treatment. We assessed the association between DCR1 methylation status and survival in patients receiving adjuvant fluorouracil/ leucovorin (5-FU/LV) or IFL. We analysed data from patients with stage III colon adenocarcinoma randomly assigned to adjuvant 5-FU/LV or IFL in CALGB 89803 (Alliance). The primary endpoint was overall survival (OS), and the secondary endpoint was disease-free survival (DFS). Using tumour sample DNA, we evaluated the association between survival, DCR1 methylation status, and molecular subgroups (BRAF, KRAS, mismatch repair status, CIMP status) using Kaplan-Meier estimator and Cox proportional hazard model. mDCR1 was observed in 221/400 (55%) colon cancers. Histopathologic features were similar between mDCR1 and unmethylated DCR1 (unDCR1) colon cancers. There was no difference in OS (p = 0.83) or DFS (p = 0.85) based on DCR1 methylation status. There was no association between methylation status and response to IFL . In patients with unDCR1 and KRAS-wildtype tumours, those who received IFL had a nearly two-fold worse DFS compared to patients who received 5-FU/LV (HR = 1.85, 95% CI (0.97-3.53, p = 0.06). This relationship was not notable among other subgroups. In stage III colon cancer patients, mDCR1 status did not associate with response to irinotecan. Larger studies may suggest an association between the iridocene response and molecular subgroups.

Association of β-Catenin, APC, SMAD3/4, Tp53, and Cyclin D1 Genes in Colorectal Cancer: A Systematic Review and Meta-Analysis

Objectives

Accumulating evidence indicates that the expression and/or variants of several genes play an essential role in the progress of colorectal cancer (CRC). The current study is a meta-analysis undertaken to estimate the prognosis and survival associated with CTNNB1/β-catenin, APC, Wnt, SMAD3/4, TP53, and Cyclin D1 genes among CRC patients.

Methods

The authors searched PubMed, EMBASE, and Science Direct for relevant reports published between 2000 and 2020 and analyzed them to determine any relationship between the (immunohistochemically/sequencing-detected) gene expression and variants of the selected genes and the survival of CRC patients.

Results

The analysis included 34,074 patients from 64 studies. To evaluate association, hazard ratios (HRs) were estimated for overall survival (OS) or disease-free survival (DFS), with a 95% confidence interval (CIs). Pooled results showed that β-catenin overexpression, APC mutation, SMAD-3 or 4 loss of expression, TP53 mutations, and Cyclin D1 expression were associated with shorter OS. β-Catenin overexpression (HR: 0.137 (95% CI: 0.131–0.406)), loss of expression of SMAD3 or 4 (HR: 0.449 (95% CI: 0.146–0.753)), the mutations of TP53 (HR: 0.179 (95% CI: 0.126–0.485)), and Cyclin D1 expression (HR: 0.485 (95% CI: 0.772–0.198)) also presented risk for shorter DFS.

Conclusions

The present meta-analysis indicates that overexpression or underexpression and variants of CTNNB1/β-catenin, APC, SMAD3/4, TP53, and Cyclin D1 genes potentially acted as unfavorable biomarkers for the prognosis of CRC. The Wnt gene was not associated with prognosis.

A model and algorithm for identifying driver pathways based on weighted non-binary mutation matrix

It is generally acknowledged that driver pathway plays a decisive role in the occurrence and progress of tumors, and the identification of driver pathways has become imperative for precision medicine or personalized medicine. Due to the inevitable sequencing error, the noise contained in single omics cancer data usually plays a negative effect on identification. It is a feasible approach to take advantage of multi-omics cancer data rather than a single one now that large amounts of multi-omics cancer data have become available. The identification of driver pathways by integrating multi-omics cancer data has attracted attention of researchers in bioinformatics recently. In this paper, a weighted non-binary mutation matrix is constructed by integrating copy number variations, somatic mutations and gene expressions. Based on the weighted non-binary mutation matrix, a new identification model is proposed through defining new measurements of coverage and exclusivity. Then, a cooperative coevolutionary algorithm CGA-MWS is put forward for solving the presented model. Both real cancer data and simulated one were used to conduct comparisons among methods Dendrix, GA, iMCMC, MOGA, PGA-MWS and CGA-MWS. Compared with the pathways identified by the other five methods, more genes, belonging to the pathway identified by the CGA-MWS method, are enriched in a known signaling pathway in most cases. Simultaneously, the high efficiency of method CGA-MWS makes it practical in realistic applications. All of which have been verified through a number of experiments.

A Novel Nine-Gene Signature Associated With Immune Infiltration for Predicting Prognosis in Hepatocellular Carcinoma

Background: Hepatocellular carcinoma (HCC) is one of the most common malignant tumors worldwide, and its prognosis remains unsatisfactory. The identification of new and effective markers is helpful for better predicting the prognosis of patients with HCC and for conducting individualized management. The oncogene Aurora kinase A (AURKA) is involved in a variety of tumors; however, its role in liver cancer is poorly understood. The aim of this study was to establish AURKA-related gene signatures for predicting the prognosis of patients with HCC.

Methods: We first analyzed the expression of AURKA in liver cancer and its prognostic significance in different data sets. Subsequently, we selected genes with prognostic value related to AURKA and constructed a gene signature based on them. The predictive ability of the gene signature was tested using the HCC cohort development and verification data sets. A nomogram was constructed by integrating the risk score and clinicopathological characteristics. Finally, the influence of the gene signature on the immune microenvironment in HCC was comprehensively analyzed.

Results: We found that AURKA was highly expressed in HCC, and it exhibited prognostic value. We selected eight AURKA-related genes with prognostic value through the protein-protein interaction network and successfully constructed a gene signature. The nine-gene signature could effectively stratify the risk of patients with HCC and demonstrated a good ability in predicting survival. The nomogram showed good discrimination and consistency of risk scores. In addition, the high-risk group showed a higher percentage of immune cell infiltration (i.e., macrophages, myeloid dendritic cells, neutrophils, and CD4+T cells). Moreover, the immune checkpoints SIGLEC15, TIGIT, CD274, HAVCR2, and PDCD1LG2 were also higher in the high-risk group versus the low-risk group.

Conclusions: This gene signature may be useful prognostic markers and therapeutic targets in patients with HCC.

The ion channel TRPM7 regulates zinc-depletion-induced MDMX degradation

Zinc deficiency has been linked to human diseases, including cancer. MDMX, a crucial zinc-containing negative regulator of p53, has been found to be amplified or overexpressed in various cancers and implicated in the cancer initiation and progression. We report here that zinc depletion by the ion chelator TPEN or Chelex resin results in MDMX protein degradation in a ubiquitination-independent and 20S proteasome-dependent manner. Restoration of zinc led to recovery of cellular levels of MDMX. Further, TPEN treatment inhibits growth of the MCF-7 breast cancer cell line, which is partially rescued by overexpression of MDMX. Moreover, in a mass-spectrometry-based proteomics analysis, we identified TRPM7, a zinc-permeable ion channel, as a novel MDMX-interacting protein. TRPM7 stabilizes and induces the appearance of faster migrating species of MDMX on SDS-PAGE. Depletion of TRPM7 attenuates, while TRPM7 overexpression facilitates, the recovery of MDMX levels upon adding back zinc to TPEN-treated cells. Importantly, we found that TRPM7 inhibition, like TPEN treatment, decreases breast cancer cell MCF-7 proliferation and migration. The inhibitory effect on cell migration upon TRPM7 inhibition is also partially rescued by overexpression of MDMX. Together, our data indicate that TRPM7 regulates cellular levels of MDMX in part by modulating the intracellular Zn²⁺ concentration to promote tumorigenesis.

The Role of p53 Dysfunction in Colorectal Cancer and Its Implication for Therapy

Colorectal cancer (CRC) is one of the most common and fatal cancers worldwide. The carcinogenesis of CRC is based on a stepwise accumulation of mutations, leading either to an activation of oncogenes or a deactivation of suppressor genes. The loss of genetic stability triggers activation of proto-oncogenes (e.g., KRAS) and inactivation of tumor suppression genes, namely TP53 and APC, which together drive the transition from adenoma to adenocarcinoma. On the one hand, p53 mutations confer resistance to classical chemotherapy but, on the other hand, they open the door for immunotherapy, as p53-mutated tumors are rich in neoantigens. Aberrant function of the TP53 gene product, p53, also affects stromal and non-stromal cells in the tumor microenvironment. Cancer-associated fibroblasts together with other immunosuppressive cells become valuable assets for the tumor by p53-mediated tumor signaling. In this review, we address the manifold implications of p53 mutations in CRC regarding therapy, treatment response and personalized medicine.

Genome-Wide Analysis of Sex Disparities in the Genetic Architecture of Lung and Colorectal Cancers

Almost all complex disorders have manifested epidemiological and clinical sex disparities which might partially arise from sex-specific genetic mechanisms. Addressing such differences can be important from a precision medicine perspective which aims to make medical interventions more personalized and effective. We investigated sex-specific genetic associations with colorectal (CRCa) and lung (LCa) cancers using genome-wide single-nucleotide polymorphisms (SNPs) data from three independent datasets. The genome-wide association analyses revealed that 33 SNPs were associated with CRCa/LCa at P < 5.0 × 10⁻⁶ neither males or females. Of these, 26 SNPs had sex-specific effects as their effect sizes were statistically different between the two sexes at a Bonferroni-adjusted significance level of 0.0015. None had proxy SNPs within their ±1 Mb regions and the closest genes to 32 SNPs were not previously associated with the corresponding cancers. The pathway enrichment analyses demonstrated the associations of 35 pathways with CRCa or LCa which were mostly implicated in immune system responses, cell cycle, and chromosome stability. The significant pathways were mostly enriched in either males or females. Our findings provided novel insights into the potential sex-specific genetic heterogeneity of CRCa and LCa at SNP and pathway levels.

Sex Differences in the Incidence of Obesity-Related Gastrointestinal Cancer

Cancer is the second leading cause of death worldwide, with 9.6 million people estimated to have died of cancer in 2018. Excess body fat deposition is a risk factor for many types of cancer. Men and women exhibit differences in body fat distribution and energy homeostasis regulation. This systematic review aimed to understand why sex disparities in obesity are associated with sex differences in the incidence of gastrointestinal cancers. Cancers of the esophagus, liver, and colon are representative gastrointestinal cancers, and obesity is a convincing risk factor for their development. Numerous epidemiological studies have found sex differences in the incidence of esophageal, liver, and colorectal cancers. We suggest that these sexual disparities are partly explained by the availability of estrogens and other genetic factors regulating inflammation, cell growth, and apoptosis. Sex differences in gut microbiota composition may contribute to differences in the incidence and phenotype of colorectal cancer. To establish successful practices in personalized nutrition and medicine, one should be aware of the sex differences in the pathophysiology and associated mechanisms of cancer development.

Exploring the Possible Mechanism and Drug Targets of Huang-Qi-Gui-Zhi-Wu-Wu Decoction for the Treatment of Chemotherapy-Induced Peripheral Neuropathy on Network Pharmacology

Chemotherapy-induced peripheral neuropathy (CIPN) is a common side effect of anticancer treatment, which may influence its successful completion. The Huang-Qi-Gui-Zhi-Wu-Wu decoction (HQGZWWD) has been widely used to treat CIPN in China although the pharmacological mechanisms involved have not been clarified. Using the network pharmacology approach, this study investigated the potential pathogenesis of CIPN and the therapeutic mechanisms exerted by the HQGZWWD herbal formula in CIPN. The targets of HQGZWWD were identified using traditional Chinese medicine (TCM) databases (TCMSP and ETCM) and prediction platforms (PharmMapper and TargetNet), and the genes of CIPN were collected by DisGeNET, GeneCards, and literature search. The common target interaction network between herbal formula and diseases was constructed by using Cytoscape. Gene Ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were used to reveal the mechanism and efficacy of HQGZWWD in the treatment of CIPN. A total of 153 CIPN-related genes were screened, and a protein-protein interaction (PPI) network with 96 nodes and 424 edges was constructed. Sixty-three active components were retrieved from HQGZWWD, with a herb-composite compound-target network including 748 nodes and 5448 edges. Forty-one targets belong to the above two networks. The analysis of network results and literature review shows that the main pathological processes of CIPN may be the inflammatory response and nerve injury, and HQGZWWD plays a therapeutic role in CIPN by regulating inflammatory response and repairing nerve injury, thus verifying the reliable efficacy of this herbal formula. In addition, we found two new potential therapeutic targets (CDK7 and GSTM2) warranting further investigation. This study fully illustrates that TCM has the characteristics of a multicompound, multitarget, and multipathway treatment, which is of great significance to study the curative effect of herbal formulations.

Genome-Wide Sex and Gender Differences in Cancer

Despite their known importance in clinical medicine, differences based on sex and gender are among the least studied factors affecting cancer susceptibility, progression, survival, and therapeutic response. In particular, the molecular mechanisms driving sex differences are poorly understood and so most approaches to precision medicine use mutational or other genomic data to assign therapy without considering how the sex of the individual might influence therapeutic efficacy. The mandate by the National Institutes of Health that research studies include sex as a biological variable has begun to expand our understanding on its importance. Sex differences in cancer may arise due to a combination of environmental, genetic, and epigenetic factors, as well as differences in gene regulation, and expression. Extensive sex differences occur genome-wide, and ultimately influence cancer biology and outcomes. In this review, we summarize the current state of knowledge about sex-specific genetic and genome-wide influences in cancer, describe how differences in response to environmental exposures and genetic and epigenetic alterations alter the trajectory of the disease, and provide insights into the importance of integrative analyses in understanding the interplay of sex and genomics in cancer. In particular, we will explore some of the emerging analytical approaches, such as the use of network methods, that are providing a deeper understanding of the drivers of differences based on sex and gender. Better understanding these complex factors and their interactions will improve cancer prevention, treatment, and outcomes for all individuals.

Genomic Alterations and Their Implications on Survival in Nonmetastatic Colorectal Cancer: Status Quo and Future Perspectives

The selection of treatment according to genomic alterations is a standard approach in metastatic colorectal cancer but is only starting to have an impact in the earlier stages of the disease. The status if genes like KRAS, BRAF, and MMR has substantial survival implications, and concerted research efforts have revolutionized treatment towards precision oncology. In contrast, a genomic-based approach has not changed the adjuvant setting after curative tumor-resection in the daily routine so far. This review focuses on the current knowledge regarding prognostic and predictive genomic biomarkers in patients with locally advanced nonmetastasized colorectal cancer. Furthermore, we provide an outlook on future challenges for a personalized adjuvant treatment approach in patients with colorectal cancer.

Landscape of somatic single nucleotide variants and indels in colorectal cancer and impact on survival

Colorectal cancer (CRC) is a biologically heterogeneous disease. To characterize its mutational profile, we conduct targeted sequencing of 205 genes for 2,105 CRC cases with survival data. Our data shows several findings in addition to enhancing the existing knowledge of CRC. We identify PRKCI, SPZ1, MUTYH, MAP2K4, FETUB, and TGFBR2 as additional genes significantly mutated in CRC. We find that among hypermutated tumors, an increased mutation burden is associated with improved CRC-specific survival (HR = 0.42, 95% CI: 0.21–0.82). Mutations in TP53 are associated with poorer CRC-specific survival, which is most pronounced in cases carrying TP53 mutations with predicted 0% transcriptional activity (HR = 1.53, 95% CI: 1.21–1.94). Furthermore, we observe differences in mutational frequency of several genes and pathways by tumor location, stage, and sex. Overall, this large study provides deep insights into somatic mutations in CRC, and their potential relationships with survival and tumor features.

Large scale sequencing study is of paramount importance to unravel the heterogeneity of colorectal cancer. Here, the authors sequenced 205 cancer genes in more than 2000 tumours and identified additional mutated driver genes, determined that mutational burden and specific mutations in TP53 are associated with survival odds.

Dietary Insulin Load and Cancer Recurrence and Survival in Patients With Stage III Colon Cancer: Findings From CALGB 89803 (Alliance)

BACKGROUND

Evidence suggests that diets inducing postprandial hyperinsulinemia may be associated with increased cancer-related mortality. The goal of this study was to assess the influence of postdiagnosis dietary insulin load and dietary insulin index on outcomes of stage III colon cancer patients.

METHODS

We conducted a prospective observational study of 1023 patients with resected stage III colon cancer enrolled in an adjuvant chemotherapy trial who reported dietary intake halfway through and six months after chemotherapy. We evaluated the association of dietary insulin load and dietary insulin index with cancer recurrence and survival using Cox proportional hazards regression adjusted for potential confounders; statistical tests were two-sided.

RESULTS

High dietary insulin load had a statistically significant association with worse disease-free survival (DFS), comparing the highest vs lowest quintile (adjusted hazard ratio [HR] = 2.77, 95% confidence interval [CI] = 1.90 to 4.02, Ptrend < .001). High dietary insulin index was also associated with worse DFS (highest vs lowest quintile, HR = 1.75, 95% CI = 1.22 to 2.51, Ptrend= .01). The association between higher dietary insulin load and worse DFS differed by body mass index and was strongest among patients with obesity (HR = 3.66, 95% CI = 1.88 to 7.12, Pinteraction = .04). The influence of dietary insulin load on cancer outcomes did not differ by mutation status of KRAS, BRAF, PIK3CA, TP53, or microsatellite instability.

CONCLUSIONS

Patients with resected stage III colon cancer who consumed a high-insulinogenic diet were at increased risk of recurrence and mortality. These findings support the importance of dietary management following resection of colon cancer, and future research into underlying mechanisms of action is warranted.

Identification of cancer sex-disparity in the functional integrity of p53 and its X chromosome network

The disproportionately high prevalence of male cancer is poorly understood. We tested for sex-disparity in the functional integrity of the major tumor suppressor p53 in sporadic cancers. Our bioinformatics analyses expose three novel levels of p53 impact on sex-disparity in 12 non-reproductive cancer types. First, TP53 mutation is more frequent in these cancers among US males than females, with poorest survival correlating with its mutation. Second, numerous X-linked genes are associated with p53, including vital genomic regulators. Males are at unique risk from alterations of their single copies of these genes. High expression of X-linked negative regulators of p53 in wild-type TP53 cancers corresponds with reduced survival. Third, females exhibit an exceptional incidence of non-expressed mutations among p53-associated X-linked genes. Our data indicate that poor survival in males is contributed by high frequencies of TP53 mutations and an inability to shield against deregulated X-linked genes that engage in p53 networks.

TP53 DNA Binding Domain Mutations Predict Progression-Free Survival of Bevacizumab Therapy in Metastatic Colorectal Cancer

(1) Background: Bevacizumab-based regimens are a standard treatment for metastatic colorectal cancer (mCRC) patients, however meaningful clinical biomarkers for treatment benefit remain scarce. (2) Methods: Tumor samples from 36 mCRC patients treated with bevacizumab-based chemotherapy underwent comprehensive genomic profiling. Alterations in frequently altered genes and important signaling pathways were correlated with progression-free survival (PFS). (3) Results: Overall genetic alteration analysis of investigated genes and pathways did not identify promising new predictors of PFS. However, when considering mutation subtypes, TP53 DNA binding domain (DBD) missense mutations were associated with prolonged PFS (HR, 0.41; 95% CI, 0.13−0.65; p = 0.005). In contrast, TP53 truncating mutations were associated with short PFS (HR, 2.95; 95% CI, 1.45−27.50; p = 0.017). Importantly, neither TP53 mutation subtype was associated with overall response rate. In multivariate analysis, TP53 DBD missense mutations remained an independent PFS predictor (HR, 0.31; 95% CI, 0.13–0.77; p = 0.011). The other genetic factor independently associated with PFS were PTPRT/PTPRD deleterious alterations, which we previously identified in a screen for biomarkers of bevacizumab response. (4) Conclusions: TP53 DBD missense mutations may predict prolonged PFS in mCRC patients treated with bevacizumab-based therapy. Analyses of TP53 mutations as clinical biomarkers should take the biological impact of different mutation subtypes into consideration to improve patient stratification.

Identifying mutated driver pathways in cancer by integrating multi-omics data

Since the driver pathway in cancer plays a crucial role in the formation and progression of cancer, it is very imperative to identify driver pathways, which will offer important information for precision medicine or personalized medicine. In this paper, an improved maximum weight submatrix problem model is proposed by integrating such three kinds of omics data as somatic mutations, copy number variations, and gene expressions. The model tries to adjust coverage and mutual exclusivity with the average weight of genes in a pathway, and simultaneously considers the correlation among genes, so that the pathway having high coverage but moderate mutual exclusivity can be identified. By introducing a kind of short chromosome code and a greedy based recombination operator, a parthenogenetic algorithm PGA-MWS is presented to solve the model. Experimental comparisons among algorithms GA, MOGA, iMCMC and PGA-MWS were performed on biological and simulated data sets. The experimental results show that, compared with the other three algorithms, the PGA-MWS one based on the improved model can identify the gene sets with high coverage but moderate mutual exclusivity and scales well. Many of the identified gene sets are involved in known signaling pathways, most of the implicated genes are oncogenes or tumor suppressors previously reported in literatures. The experimental results indicate that the proposed approach may become a useful complementary tool for detecting cancer pathways.

Human colon cancer cells highly express myoferlin to maintain a fit mitochondrial network and escape p53-driven apoptosis

Colon adenocarcinoma is the third most commonly diagnosed cancer and the second deadliest one. Metabolic reprogramming, described as an emerging hallmark of malignant cells, includes the predominant use of glycolysis to produce energy. Recent studies demonstrated that mitochondrial electron transport chain inhibitor reduced colon cancer tumour growth. Accumulating evidence show that myoferlin, a member of the ferlin family, is highly expressed in several cancer types, where it acts as a tumour promoter and participates in the metabolic rewiring towards oxidative metabolism. In this study, we showed that myoferlin expression in colon cancer lesions is associated with low patient survival and is higher than in non-tumoural adjacent tissue. Human colon cancer cells silenced for myoferlin exhibit a reduced oxidative phosphorylation activity associated with mitochondrial fission leading, ROS accumulation, decreased cell growth, and increased apoptosis. We observed the triggering of a DNA damage response culminating to a cell cycle arrest in wild-type p53 cells. The use of a p53 null cell line or a compound able to restore p53 activity (Prima-1) reverted the effects induced by myoferlin silencing, confirming the involvement of p53. The recent identification of a compound interacting with a myoferlin C2 domain and bearing anticancer potency identifies, together with our demonstration, this protein as a suitable new therapeutic target in colon cancer.

Associations of artificially sweetened beverage intake with disease recurrence and mortality in stage III colon cancer: Results from CALGB 89803 (Alliance)

Purpose

Observational studies have demonstrated increased colon cancer recurrence and mortality in states of excess energy balance, as denoted by factors including sedentary lifestyle, diabetes, increased dietary glycemic load, and increased intake of sugar-sweetened beverages. Nonetheless, the relation between artificially sweetened beverages, a popular alternative for sugar-sweetened beverages, and colon cancer recurrence and survival is unknown.

Methods

We analyzed data from 1,018 patients with stage III colon cancer who prospectively reported dietary intake during and after chemotherapy while enrolled in a National Cancer Institute-sponsored trial of adjuvant chemotherapy. Using Cox proportional hazards regressions, we assessed associations of artificially sweetened beverage intake with cancer recurrence and mortality.

Results

Patients consuming one or more 12-ounce servings of artificially sweetened beverages per day experienced an adjusted hazard ratio for cancer recurrence or mortality of 0.54 (95% confidence interval, 0.36 to 0.80) when compared to those who largely abstained (P_trend = .004). Similarly, increasing artificially sweetened beverage intake was also associated with a significant improvement in both recurrence-free survival (P_trend = .005) and overall survival (P_trend = .02). Substitution models demonstrated that replacing a 12-ounce serving of a sugar-sweetened beverage with an isovolumetric serving of an artificially sweetened beverage per day was associated with a 23% lower risk of cancer recurrence and mortality (relative risk, 0.77; 95% confidence interval, 0.63 to 0.95; P = .02).

Conclusion

Higher artificially sweetened beverage consumption may be associated with significantly reduced cancer recurrence and death in patients with stage III colon cancer. This association may be mediated by substitution for sugar-sweetened alternatives. Further studies are needed to confirm these findings.

Improved potency of F10 relative to 5-fluorouracil in colorectal cancer cells with p53 mutations

Aim:

Resistance to fluoropyrimidine drugs (FPs) is a major cause of mortality in colorectal cancer (CRC). We assessed the potency advantage of the polymeric FP F10 relative to 5-fluorouracil (5FU) in four human CRC cell lines that differ only in TP53 mutational status to determine how p53 mutations affect drug response and whether F10 is likely to improve outcomes.

Methods:

HCT-116 human CRC cells (p53^+/+) and three isogenic variants (p53^−/−, R248W/+, R248W/−) were assessed for drug response. Resistance factors were derived from cell viability data and used to establish the relative potency advantage for F10. Rescue studies with exogenous uridine/thymidine determined if cytotoxicity resulted from DNA-directed processes.

Results:

Significant resistance to 5-FU resulted from p53-loss or from gain-of-function (GOF) mutation (R248W) and was greatest when GOF mutation was coupled with loss of wild-type p53. F10 is much more potent than 5-FU (137–314-fold depending on TP53 mutational status). F10 and 5-FU induce apoptosis by DNA- and RNA-directed mechanisms, respectively, and only F10 shows a modest enhancement in cytotoxicity upon co-treatment with leucovorin.

Conclusion:

TP53 mutational status affects inherent sensitivity to FPs, with p53 GOF mutations most deleterious. F10 is much more effective than 5-FU regardless of TP53 mutations and has potential to be effective to CRC that is resistant to 5-FU due, in part, to TP53 mutations.6,7

Nut Consumption and Survival in Patients With Stage III Colon Cancer: Results From CALGB 89803 (Alliance)

Purpose

Observational studies have reported increased colon cancer recurrence and mortality in patients with states of hyperinsulinemia, including type 2 diabetes, obesity, sedentary lifestyle, and high glycemic load diet. Nut intake has been associated with a lower risk of type 2 diabetes, metabolic syndrome, and insulin resistance. However, the effect of nut intake on colon cancer recurrence and survival is not known.

Patients and Methods

We conducted a prospective, observational study of 826 eligible patients with stage III colon cancer who reported dietary intake on food frequency questionnaires while enrolled onto a randomized adjuvant chemotherapy trial. Using Cox proportional hazards regression, we assessed associations of nut intake with cancer recurrence and mortality.

Results

After a median follow-up of 6.5 years, compared with patients who abstained from nuts, individuals who consumed two or more servings of nuts per week experienced an adjusted hazard ratio (HR) for disease-free survival of 0.58 (95% CI, 0.37 to 0.92; P_trend = .03) and an HR for overall survival of 0.43 (95% CI, 0.25 to 0.74; P_trend = .01). In subgroup analysis, the apparent benefit was confined to tree nut intake (HR for disease-free survival, 0.54; 95% CI, 0.34 to 0.85; P_trend = .04; and HR for overall survival, 0.47; 95% CI, 0.27 to 0.82; P_trend = .04). The association of total nut intake with improved outcomes was maintained across other known or suspected risk factors for cancer recurrence and mortality.

Conclusion

Diets with a higher consumption of nuts may be associated with a significantly reduced incidence of cancer recurrence and death in patients with stage III colon cancer.

PIK3CA and TP53 mutations predict overall survival of stage II/III colorectal cancer patients

AIM

To investigate the predictive value of PIK3CA and TP53 mutation status in colorectal cancer (CRC) patients treated with 5-fluorouracil-based chemotherapy.

METHODS

In this study, a total of 315 patients with histologically proven CRC were enrolled from Yangpu Hospital affiliated to Shanghai Tongji University between 2007 and 2011. Of these patients, 241 with stage II/III CRC received 5-fluorouracil-based adjuvant chemotherapy. Formalin-fixed paraffin-embedded lesion samples of the patients with curatively resected CRC were collected. Next-generation sequencing was performed to identify somatic gene mutations. The correlation of PIK3CA and TP53 mutation status with overall survival (OS) was analyzed using a Cox proportional hazard model and the Kaplan-Meier method.

RESULTS

Among the 241 patients with stage II/III in this cohort, the PIK3CA and/or TP53 mutation was detected in 177 patients, among which 54 patients had PIK3CA and TP53 double mutations. The PIK3CA or TP53 mutation was not significantly correlated with OS in univariate and multivariate analyses. Compared with patients without PIK3CA and TP53 mutations, those with double PIK3CA-TP53 mutations showed a significantly worse survival (univariate HR = 2.21; 95%CI: 1.15-4.24; multivariate HR = 2.02; 95%CI: 1.04-3.91). The PIK3CA mutation located in the kinase domain showed a trend toward a shorter OS compared with wild-type tumors (multivariate HR = 1.56; 95%CI: 1.00-2.44; P = 0.052). The Kaplan-Meier curve showed that patients harboring the PIK3CA mutation located in the kinase domain had a worse clinical outcome than those with wild-type status (Log-rank P = 0.041)

CONCLUSION

Double mutation of PIK3CA and TP53 is correlated with a shorter OS in stage II/III CRC patients treated with 5-fluorouracil-based therapy.

Major challenges related to tumor biological characteristics in accurate mutation detection of colorectal cancer by next-generation sequencing

Next-generation sequencing (NGS) has been used in mutation detection of colorectal cancer (CRC). We here interrogated 747 CRC samples to detect mutations in 22 cancer-related genes by using NGS, and to explore some key challenges related to tumor biology. RAS mutations (KRAS or NRAS mutations), RAS/BRAF/PIK3CA mutations (mutations in KRAS, NRAS, BRAF or PIK3CA) and mutation burden (mutations in any of the 22 detected genes) were observed in 53.0% (396/747), 57.1% (431/747) and 84.2% (629/747) of specimens, respectively. Higher mutation frequencies were observed in biopsy specimens with ≥20% tumor cellularity than those with <20% tumor cellularity, but these differences were not observed in resection samples. Intratumor mutational heterogeneity was estimated by mutant allele frequency and tumor cellularity, and more likely to occur in PIK3CA mutant tumors. No significant differences of mutation frequencies were detected between primary and metastatic tumors. Additionally, specimens after chemotherapy showed lower mutation frequencies compared with specimens without chemotherapy. Together, our findings demonstrate that poor tumor cellularity, tumor heterogeneity and adjuvant therapy may confound the molecular diagnosis of CRC, and should be highlighted with prospective quality assessment during tissue process.

Gender differences in colorectal cancer survival: A meta-analysis

A meta-analysis was conducted to determine the influence of gender on overall survival (OS) and cancer-specific survival (CSS) in colorectal cancer patients. Major databases were searched for clinical trials, which compare survival differences between male and female for colorectal cancer patients. A list of these studies and references, published in English and Chinese from 1960 to 2017, was obtained independently by two reviewers from databases such as PubMed, Medline, ScienceDirect, the China National Knowledge Infrastructure (CNKI) and Web of Science. Overall survival and cancer-specific survival were compared using Review Manager 5.3. Females had significantly better OS (hazard ratio [HR] = 0.87; 95% confidence interval [CI] = 0.85-0.89) and CSS (HR = 0.92; 95% CI = 0.89-0.95) than males after meta-analysis. These results suggest that gender seems to be a significant factor influencing survival results among colorectal cancer patients.

A plant alkaloid, veratridine, potentiates cancer chemosensitivity by UBXN2A-dependent inhibition of an oncoprotein, mortalin-2

Veratridine (VTD), an alkaloid derived from the Liliaceae plant shows anti-tumor effects; however, its molecular targets have not been thoroughly studied. Using a high-throughput drug screen, we found that VTD enhances transactivation of UBXN2A, resulting in upregulation of UBXN2A in the cytoplasm, where UBXN2A binds and inhibits the oncoprotein mortalin-2 (mot-2). VTD-treated cancer cells undergo cell death in UBXN2A- and mot-2-dependent manners. The cytotoxic function of VTD is grade-dependent, and the combined treatment with a sub-optimal dose of the standard chemotherapy, 5-Fluorouracil (5-FU) and etoposide, demonstrated a synergistic effect, resulting in higher therapeutic efficacy. VTD influences the CD44+ stem cells, possibly through UBXN2A-dependent inhibition of mot-2. The VTD-dependent expression of UBXN2A is a potential candidate for designing novel strategies for colon cancer treatment because: 1) In 50% of colon cancer patients, UBXN2A protein levels in tumor tissues are significantly lower than those in the adjacent normal tissues. 2) Cytoplasmic expression of the mot-2 protein is very low in non-cancerous cells; thus, VTD can produce tumor-specific toxicity while normal cells remain intact. 3) Finally, VTD or its modified analogs offer a valuable adjuvant chemotherapy strategy to improve the efficacy of 5-FU-based chemotherapy for colon cancer patients harboring WT-p53.

Gender-Specific Molecular and Clinical Features Underlie Malignant Pleural Mesothelioma

Malignant pleural mesothelioma (MPM) is an aggressive cancer that occurs more frequently in men, but is associated with longer survival in women. Insight into the survival advantage of female patients may advance the molecular understanding of MPM and identify therapeutic interventions that will improve the prognosis for all MPM patients. In this study, we performed whole-genome sequencing of tumor specimens from 10 MPM patients and matched control samples to identify potential driver mutations underlying MPM. We identified molecular differences associated with gender and histology. Specifically, single-nucleotide variants of BAP1 were observed in 21% of cases, with lower mutation rates observed in sarcomatoid MPM (P < 0.001). Chromosome 22q loss was more frequently associated with the epithelioid than that nonepitheliod histology (P = 0.037), whereas CDKN2A deletions occurred more frequently in nonepithelioid subtypes among men (P = 0.021) and were correlated with shorter overall survival for the entire cohort (P = 0.002) and for men (P = 0.012). Furthermore, women were more likely to harbor TP53 mutations (P = 0.004). Novel mutations were found in genes associated with the integrin-linked kinase pathway, including MYH9 and RHOA. Moreover, expression levels of BAP1, MYH9, and RHOA were significantly higher in nonepithelioid tumors, and were associated with significant reduction in survival of the entire cohort and across gender subgroups. Collectively, our findings indicate that diverse mechanisms highly related to gender and histology appear to drive MPM.

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 - βR (9.6%) mutation frequencies were significantly higher in proximal colon cancer. The high MSI (35.6%) and BRAF (20.3%), TGF - βR (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.

Defective Mismatch Repair Status was not Associated with DFS and OS in Stage II Colon Cancer Treated with Adjuvant Chemotherapy

BACKGROUND

Mismatch repair (MMR) status has been proposed, with some controversy, as a prognostic and predictive marker in stage II colon cancer. The aim of this study was to evaluate the association between MMR and survival in stage II colon cancer.

METHODS

A total of 860 patients with curatively resected stage II colon cancer were selected for inclusion between January 2003 and December 2008. Tumors lacking expression of MLH1 and/or MSH2, as determined by immunohistochemistry, were classified as having deficient MMR (dMMR), whereas other tumors were classified as having proficient MMR (pMMR). Clinical risk (CR) factors were used to divide patients into high or standard CR groups.

RESULTS

Of 860 patients, 14.7 % were dMMR, 42.4 % had ≥1 CR factors, and 85.8 % patients received adjuvant chemotherapy. MMR status did not affect disease-free survival (DFS; hazard ratio [HR] 1.191, p = 0.415) or overall survival (OS; HR 1.300, p = 0.344). Among CR factors, only pathologic T4 disease tended to associate with poor OS (HR 1.979, p = 0.071). Adjuvant chemotherapy was associated with better DFS (HR 0.393, p < 0.0001) in patients with pMMR tumors. However, in patients with dMMR tumors, adjuvant chemotherapy was not associated with DFS.

CONCLUSIONS

MMR status did not affect DFS or OS in patients with stage II colon cancer. In patients treated with adjuvant chemotherapy, dMMR was not associated with DFS and OS. However, adjuvant chemotherapy was associated with improved DFS in pMMR patients.

Chemoradiation provides a physiological selective pressure that increases the expansion of aberrant TP53 tumor variants in residual rectal cancerous regions

Neoadjuvant chemoradiotherapy has been introduced in patients with surgically resected rectal cancer and reduced the local recurrence. Heterogeneity exists in rectal cancer, and we hypothesized that there are subclones resistant to chemoradiotherapy within the cancer mass.

We performed DNA-targeted sequencing of pre- and post-treatment tumor tissues obtained from 20 rectal cancer patients who received chemoradiotherapy. The variant frequency of the mutant clones was compared between pre- and post-treatment samples of nine non-responder patients. RNA-targeted sequencing of 57 genes related to sensitivity to chemotherapy and radiotherapy was performed for the paired samples. Immunohistochemical analyses of p53 expression were also performed on the paired samples from the nine non-responder patients.

DNA-sequencing detected frequent mutations of suppressor genes including TP53, APC and FBXW7 in the post-treatment samples of the nine non-responders. The frequency of TP53 mutations showed significant increases after chemoradiotherapy. RNA-targeted sequencing of 29 tumor tissues demonstrated that decreased expression of three genes and increased expression of four genes were detected in the post-treatment samples. Significantly increased expression of TP53 was observed in the post-treatment samples. Immunohistochemical staining for p53 revealed that increased p53 intensity scores were observed after chemoradiotherapy. These results suggest that the tumors with TP53 mutations tend to accumulate through chemoradiotherapy.

Sex- and gender-specific disparities in colorectal cancer risk

Colorectal cancer is one of the most common causes of cancer morbidity both in men and in women. However, females over 65 years old show higher mortality and lower 5-year survival rate of colorectal cancer compared to their age-matched male counterparts. The objective of this review is to suggest gender-based innovations to improve colorectal cancer outcomes in females. Women have a higher risk of developing right-sided (proximal) colon cancer than men, which is associated with more aggressive form of neoplasia compared to left-sided (distal) colon cancer. Despite differences in tumor location between women and men, most of scientific researchers do not consider sex specificity for study design and interpretation. Also, colorectal cancer screening guidelines do not distinguish females from male, which may explain the higher frequency of more advanced neoplasia when tumors are first detected and false negative results in colonoscopy in females. Moreover, socio-cultural barriers within females are present to delay screening and diagnosis. Few studies, among studies that included both men and women, have reported sex-specific estimates of dietary risk factors which are crucial to establish cancer prevention guidelines despite sex- and gender-associated differences in nutrient metabolism and dietary practices. Furthermore, anti-cancer drug use for colorectal cancer treatment can cause toxicity to the reproductive system, and gender-specific recurrence and survival rates are reported. Therefore, by understanding sex- and gender-related biological and socio-cultural differences in colorectal cancer risk, gender-specific strategies for screening, treatment and prevention protocols can be established to reduce the mortality and improve the quality of life.

Sex- and gender-specific disparities in colorectal cancer risk

Colorectal cancer is one of the most common causes of cancer morbidity both in men and in women. However, females over 65 years old show higher mortality and lower 5-year survival rate of colorectal cancer compared to their age-matched male counterparts. The objective of this review is to suggest gender-based innovations to improve colorectal cancer outcomes in females. Women have a higher risk of developing right-sided (proximal) colon cancer than men, which is associated with more aggressive form of neoplasia compared to left-sided (distal) colon cancer. Despite differences in tumor location between women and men, most of scientific researchers do not consider sex specificity for study design and interpretation. Also, colorectal cancer screening guidelines do not distinguish females from male, which may explain the higher frequency of more advanced neoplasia when tumors are first detected and false negative results in colonoscopy in females. Moreover, socio-cultural barriers within females are present to delay screening and diagnosis. Few studies, among studies that included both men and women, have reported sex-specific estimates of dietary risk factors which are crucial to establish cancer prevention guidelines despite sex- and gender-associated differences in nutrient metabolism and dietary practices. Furthermore, anti-cancer drug use for colorectal cancer treatment can cause toxicity to the reproductive system, and gender-specific recurrence and survival rates are reported. Therefore, by understanding sex- and gender-related biological and socio-cultural differences in colorectal cancer risk, gender-specific strategies for screening, treatment and prevention protocols can be established to reduce the mortality and improve the quality of life.

CpG island methylator phenotype is associated with response to adjuvant irinotecan-based therapy for stage III colon cancer

BACKGROUND & AIMS

The CpG island methylator phenotype (CIMP), defined by a high frequency of aberrantly methylated genes, is a characteristic of a subclass of colon tumors with distinct clinical and molecular features. Cohort studies have produced conflicting results on responses of CIMP-positive tumors to chemotherapy. We assessed the association between tumor CIMP status and survival of patients receiving adjuvant fluorouracil and leucovorin alone or with irinotecan (IFL).

METHODS

We analyzed data from patients with stage III colon adenocarcinoma randomly assigned to groups given fluorouracil and leucovorin or IFL after surgery, from April 1999 through April 2001. The primary end point of the trial was overall survival and the secondary end point was disease-free survival. DNA isolated from available tumor samples (n = 615) was used to determine CIMP status based on methylation patterns at the CACNA1G, IGF2, NEUROG1, RUNX3, and SOCS1 loci. The effects of CIMP on survival were modeled using Kaplan-Meier and Cox proportional hazards; interactions with treatment and BRAF, KRAS, and mismatch repair (MMR) status were also investigated.

RESULTS

Of the tumor samples characterized for CIMP status, 145 were CIMP positive (23%). Patients with CIMP-positive tumors had shorter overall survival times than patients with CIMP-negative tumors (hazard ratio = 1.36; 95% confidence interval: 1.01-1.84). Treatment with IFL showed a trend toward increased overall survival for patients with CIMP-positive tumors, compared with treatment with fluorouracil and leucovorin (hazard ratio = 0.62; 95% CI: 0.37-1.05; P = .07), but not for patients with CIMP-negative tumors (hazard ratio = 1.38; 95% CI: 1.00-1.89; P = .049). In a 3-way interaction analysis, patients with CIMP-positive, MMR-intact tumors benefited most from the addition of irinotecan to fluorouracil and leucovorin therapy (for the interaction, P = .01). CIMP was more strongly associated with response to IFL than MMR status. Results for disease-free survival times were comparable among all analyses.

CONCLUSIONS

Patients with stage III, CIMP-positive, MMR-intact colon tumors have longer survival times when irinotecan is added to combination therapy with fluorouracil and leucovorin.