Molecular prognostic markers in locally advanced colon cancer

Clinical relevance and prognostic role of preoperative cell-free single-stranded DNA concentrations in colorectal cancer patients

PURPOSE

Circulating cell-free single-stranded DNA (ccf-ssDNA) is extracellular DNA and it is a useful biomarker for the diagnosis of tumors and predicting the prognosis of tumors. However, the clinical usefulness of ccf-ssDNA in colorectal cancer (CRC) is not well known. Thus, the purpose of this study was to investigate the clinical usefulness of ccf-ssDNA in CRC.

METHODS

The study was conducted on 44 patients who had undergone surgery for CRC, and ccf-ssDNA level was measured before surgery and statistical analysis was performed on clinical factors.

RESULTS

The association between ccf-ssDNA level and clinicopathological factors was analyzed and compared, and these factors included age, sex, body mass index, diabetes mellitus, hypertension, tumor markers (carcinoembryonic antigen and carbohydrate antigen 19-9), tumor location, size, stage (TNM), recurrence, and death. The group with a ccf-ssDNA level of ≥7.5 ng/μL had a lower age (P=0.010), and was associated with diabetes mellitus (P=0.037) and lymph node metastasis (P=0.049). Multivariate analysis of disease-free survival showed that lymph node metastasis and ccf-ssDNA level (hazard ratio, 10.011; 95% confidence interval, 2.269-44.175; P=0.002) were independent prognostic factors for recurrence. In terms of overall survival, there were no statistically significant results except for vascular invasion.

CONCLUSION

This study showed that ccf-ssDNA level in plasma in CRC patients was an independent prognostic factor that could predict recurrence non-invasively. In this regard, further evaluation with a prospective, large sample size study will be needed to obtain additional results.

Prognostic significance of chemokines CCL11 and CCL5 modulated by low-density lipoprotein cholesterol in colon cancer patients with normal body mass index

Background

Many studies have shown an elevated level of cholesterol in colon tumors as compared to normal tissue. Obesity and high low-density lipoprotein cholesterol (LDL-C) are known risk factors for colon cancer. However, the role of LDL-C in colon cancer patients with normal body mass index (BMI) remains elusive.

Methods

Levels of serum cholesterol and oxysterols were quantified by ultra-performance liquid chromatography-tandem mass spectrometer (UPLC-MS/MS) from 129 individuals with normal BMI, including 32 with solitary polyp, 36 with multiple polyps, and 31 with adenocarcinoma as well as 32 healthy controls. In vitro, colon cancer cells were treated with LDL-C and assayed for chemokines via RNA-Seq and mitochondrial morphology via transmission electron microscopy and immunofluorescence. Additionally, correlation analysis was performed between LDL-C-induced chemokines and the overall survival of colon cancer patients from the Cancer Genome Atlas (TCGA), the Genotype-Tissue Expression (GTEx), and the Human Protein Atlas (HPA) database.

Results

The serum cholesterol level was significantly higher in colon adenocarcinoma patients with normal BMI than that in healthy controls (P<0.001). LDL-C potentiated colon cancer cell invasion and resistance to glucose-deprivation in vitro via chemokine-mediated signaling, mainly upregulation of CC chemokine ligand (CCL) 5 and downregulation of CCL 11. By analyzing the RNA expression data of colorectal cancer from TCGA, GTEx, and HPA, we demonstrated that the CCL5 level in colorectal adenocarcinoma tissues was significantly increased relative to adjacent normal tissues (P=0.01) while the CCL11 level was decreased (P=0.01). Both increased CCL5 and decreased CCL11 showed a negative correlation with the 5-year overall survival in tumor node metastasis (TNM) stage II colon cancer patients (P=0.0032, 0.026 for CCL5 and CCL11, respectively).

Conclusions

Our study supports the idea that LDL-C regulates the expression of CCL5 and CCL11 chemokines, which may have predictive values for survival in colon cancer patients with normal BMI, especially for patients in TNM stage II.

Farnesyl dimethyl chromanol targets colon cancer stem cells and prevents colorectal cancer metastasis

The activation and growth of tumour-initiating cells with stem-like properties in distant organs characterize colorectal cancer (CRC) growth and metastasis. Thus, inhibition of colon cancer stem cell (CCSC) growth holds promise for CRC growth and metastasis prevention. We and others have shown that farnesyl dimethyl chromanol (FDMC) inhibits cancer cell growth and induces apoptosis in vitro and in vivo. We provide the first demonstration that FDMC inhibits CCSC viability, survival, self-renewal (spheroid formation), pluripotent transcription factors (Nanog, Oct4, and Sox2) expression, organoids formation, and Wnt/β-catenin signalling, as evidenced by comparisons with vehicle-treated controls. In addition, FDMC inhibits CCSC migration, invasion, inflammation (NF-kB), angiogenesis (vascular endothelial growth factor, VEGF), and metastasis (MMP9), which are critical tumour metastasis processes. Moreover, FDMC induced apoptosis (TUNEL, Annexin V, cleaved caspase 3, and cleaved PARP) in CCSCs and CCSC-derived spheroids and organoids. Finally, in an orthotopic (cecum-injected CCSCs) xenograft metastasis model, we show that FDMC significantly retards CCSC-derived tumour growth (Ki-67); inhibits inflammation (NF-kB), angiogenesis (VEGF and CD31), and β-catenin signalling; and induces apoptosis (cleaved PARP) in tumour tissues and inhibits liver metastasis. In summary, our results demonstrate that FDMC inhibits the CCSC metastatic phenotype and thereby supports investigating its ability to prevent CRC metastases.

Precision medicine for adjuvant chemotherapy of resected colorectal cancer

Colorectal cancer (CRC) is the most common cancer and the second leading cause of cancer death in Japan. Surgical resection is the only curative option for localized disease. However, undetectable micrometastases remaining after curative surgery may cause disease recurrence. Adjuvant chemotherapy aims to eradicate these micrometastases to improve the cure rate. Unfortunately, few reliable prognostic and predictive markers are available that identify patients at high risk for CRC during early-stage disease. However, promising biomarkers may become available in the near future. Such biomarkers provide information for stratifying a patient's risk and for selecting the optimal treatment. Here, we provide an overview of current relevant prognostic and predictive biomarkers applicable to adjuvant treatment of early-stage CRC and focus on the future of this field.

Lymphocyte-C-reactive Protein Ratio as Promising New Marker for Predicting Surgical and Oncological Outcomes in Colorectal Cancer

BACKGROUND

Systemic inflammation via host-tumor interactions is currently recognized as a hallmark of cancer. The aim of this study was to evaluate the prognostic value of various combinations of inflammatory factors using preoperative blood, and to assess the clinical significance of our newly developed inflammatory score in colorectal cancer (CRC) patients.

METHOD

In total 477 CRC patients from the discovery and validation cohorts were enrolled in this study. We assessed the predictive impact for recurrence using a combination of nine inflammatory markers in the discovery set, and focused on lymphocyte-C-reactive protein ratio (LCR) to elucidate its prognostic and predictive value for peri-operative risk in both cohorts.

RESULTS

A combination of lymphocytic count along with C-reactive protein levels demonstrated the highest correlation with recurrence compared with other parameters in CRC patients. Lower levels of preoperative LCR significantly correlated with undifferentiated histology, advanced T stage, presence of lymph node metastasis, distant metastasis, and advanced stage classification. Decreased preoperative LCR (using an optimal cut-off threshold of 6000) was an independent prognostic factor for both disease-free survival and overall survival, and emerged as an independent risk factor for postoperative complications and surgical-site infections in CRC patients. Finally, we assessed the clinical feasibility of LCR in an independent validation cohort, and confirmed that decreased preoperative LCR was an independent prognostic factor for both disease-free survival and overall survival, and was an independent predictor for postoperative complications and surgical-site infections in CRC patients.

CONCLUSION

Preoperative LCR is a useful marker for perioperative and postoperative management of CRC patients.

Modified neutrophil-platelet score as a promising marker for stratified surgical and oncological outcomes of patients with gastric cancer

PURPOSE

Gastric cancer (GC) is a common malignancy, especially in East Asian countries. There is emerging evidence that circulating neutrophil and platelet levels correlate with cancer progression. We evaluated the short- and long-term outcomes of GC patients systemically, to compare the original neutrophil-platelet score (NPS) and our modified NPS (mNPS).

METHODS

We analyzed the original pre-operative NPS and the mNPS of 621 GC patients.

RESULTS

Racial differences between the United Kingdom and East Asian countries accounted for compelling deviation in classification using the original NPS, which could not reliably stratify the prognoses of Japanese GC patients. We developed the mNPS using appropriate cutoff levels for pre-operative neutrophils and platelets, and demonstrated that the pre-operative mNPS was significantly correlated with all of the well-established clinicopathological factors for disease development, including advanced T stage, venous and lymphatic vessel invasion, lymph node/peritoneal /distant metastasis, and tumor-node-metastasis stage. The pre-operative mNPS could stratify prognostication for both overall survival (OS) and disease-free survival (DFS): a high pre-operative mNPS was an independent prognostic factor for the OS and DFS of GC patients and also an independent predictor of post-operative surgical site infection after gastrectomy.

CONCLUSION

Calculating the mNPS could help clinicians to stratify the surgical and oncological risks of patients with GC.

In silico learning of tumor evolution through mutational time series

Cancer is caused by the effects of somatic mutations known as drivers. Although a number of major cancer drivers have been identified, it is suspected that many more comparatively rare and conditional drivers exist, and the interactions between different cancer-associated mutations that might be relevant for tumor progression are not well understood. We applied an advanced neural network approach to learn the sequence of mutations and the mutational burden in colon and lung cancers and to identify mutations that are associated with individual drivers. A significant ordering of driver mutations is demonstrated, and numerous, previously undetected conditional drivers are identified. These findings broaden the existing understanding of the mechanisms of tumor progression and have implications for therapeutic strategies.

Cancer arises through the accumulation of somatic mutations over time. Understanding the sequence of mutation occurrence during cancer progression can assist early and accurate diagnosis and improve clinical decision-making. Here we employ long short-term memory (LSTM) networks, a class of recurrent neural network, to learn the evolution of a tumor through an ordered sequence of mutations. We demonstrate the capacity of LSTMs to learn complex dynamics of the mutational time series governing tumor progression, allowing accurate prediction of the mutational burden and the occurrence of mutations in the sequence. Using the probabilities learned by the LSTM, we simulate mutational data and show that the simulation results are statistically indistinguishable from the empirical data. We identify passenger mutations that are significantly associated with established cancer drivers in the sequence and demonstrate that the genes carrying these mutations are substantially enriched in interactions with the corresponding driver genes. Breaking the network into modules consisting of driver genes and their interactors, we show that these interactions are associated with poor patient prognosis, thus likely conferring growth advantage for tumor progression. Thus, application of LSTM provides for prediction of numerous additional conditional drivers and reveals hitherto unknown aspects of cancer evolution.

An integrated computational and experimental study uncovers FUT9 as a metabolic driver of colorectal cancer

Metabolic alterations play an important role in cancer and yet, few metabolic cancer driver genes are known. Here we perform a combined genomic and metabolic modeling analysis searching for metabolic drivers of colorectal cancer. Our analysis predicts FUT9, which catalyzes the biosynthesis of Ley glycolipids, as a driver of advanced-stage colon cancer. Experimental testing reveals FUT9's complex dual role; while its knockdown enhances proliferation and migration in monolayers, it suppresses colon cancer cells expansion in tumorspheres and inhibits tumor development in a mouse xenograft models. These results suggest that FUT9's inhibition may attenuate tumor-initiating cells (TICs) that are known to dominate tumorspheres and early tumor growth, but promote bulk tumor cells. In agreement, we find that FUT9 silencing decreases the expression of the colorectal cancer TIC marker CD44 and the level of the OCT4 transcription factor, which is known to support cancer stemness. Beyond its current application, this work presents a novel genomic and metabolic modeling computational approach that can facilitate the systematic discovery of metabolic driver genes in other types of cancer.

Role of LOXL2 in the epithelial-mesenchymal transition and colorectal cancer metastasis

Colorectal cancer (CRC) is one of the most dangerous types of malignant tumors, and cancer metastasis is a major factor in the failure of CRC therapy. Recently, LOXL2 (lysyl oxidase-like 2) has been shown to represent a regulator of epithelial-mesenchymal transition (EMT) in different cancer types. However, LOXL2 has not been reported to be involved in CRC metastasis. In this study, we demonstrated that LOXL2 expression is strongly correlated with the rate of CRC metastasis, it participates in the regulation of EMT-related molecule expression in CRC cells in vitro, and it is involved in migratory potential alterations. Additionally, tissue microarray analysis of CRC patients showed an increase in the probability of developing CRC distant metastasis and a decrease in the survival rate of patients with high LOXL2 expression. The results obtained in this study indicate that LOXL2 is involved in the development and progression of CRC metastasis, and therefore, its expression levels may represent a useful prognostic marker.

Protein Markers Associated with an ALDH Sub-Population in Colorectal Cancer

ALDH has been shown to be a marker that denotes a sub-population of cancer stem cells in colorectal and other cancers. This sub-population of cells shows an increased risk for tumor initiation, metastasis, and resistance to chemotherapy and radiation resulting in recurrence and death. It is thus essential to identify the important signaling pathways related to ALDH1+ CSCs in colon cancer. The essential issue becomes to isolate pure sub-populations of cells from heterogeneous tissues for further analysis. To achieve this goal, tissues from colorectal cancer Stage III patients were immuno-stained with ALDH1 antibody. Target ALDH1+ and ALDH1- cells from the same tissue were micro-dissected using Laser Capture Microdissection (LCM). Captured cells were lysed and analyzed using LC-MS/MS where around 20,000 cells were available for analysis. This analysis resulted in 134 proteins which were differentially expressed between ALDH1+ and ALDH1- cells in three patient sample pairs. Based on these differentially expressed proteins an IPA pathway analysis was performed that showed two key pathways in cell to cell signaling and organismal injury and abnormalities. The IPA analysis revealed β-catenin, NFκB (p65) and TGFβ1 as important cancer-related proteins in these pathways. A TMA validation using immunofluorescence staining of tissue micro-arrays including 170 cases was used to verify that these key proteins were highly overexpressed in ALDH1+ cells in colon cancer tissues compared to ALDH1- cells.

miRNA-503 Promotes Tumor Progression and Is Associated with Early Recurrence and Poor Prognosis in Human Colorectal Cancer

OBJECTIVES

MicroRNA (miR)-503 is downregulated in several cancers and plays a tumor-suppressive role in carcinogenesis. However, the miR-503 expression pattern, its clinical significance and its molecular mechanism in colorectal cancer (CRC) have not been investigated.

METHODS

We analyzed miR-503 expression in normal mucosa (n = 20), adenoma (n = 27) and CRC (n = 20). We quantified miR-503 expression in an independent cohort (n = 191) and investigated the clinical significance of miR-503 in CRC. CRC cell lines were transfected with anti-miR-503 to assess its function and target gene.

RESULTS

miR-503 expression increased according to the adenoma-carcinoma sequence. High miR-503 expression was significantly associated with large tumor size, serosal invasion, lymphatic and venous invasion as well as lymph node metastasis. CRC patients with high miR-503 expression had significantly earlier relapse and poorer prognosis than those with low expression. miR-503 was an independent recurrence marker in stage I/II CRC. In vitro, attenuated miR-503 expression resulted in inhibition of proliferation, invasion and migration and acquisition of anoikis of CRC cells. The putative target gene (calcium-sensing receptor) was significantly upregulated after miR-503 attenuation.

CONCLUSIONS

miR-503 acts as an 'onco-miR' in CRC. High miR-503 expression is associated with early recurrence and poor prognosis in CRC.

Eicosanoid pathway in colorectal cancer: Recent updates

Enzymatic metabolism of the 20C polyunsaturated fatty acid (PUFA) arachidonic acid (AA) occurs via the cyclooxygenase (COX) and lipoxygenase (LOX) pathways, and leads to the production of various bioactive lipids termed eicosanoids. These eicosanoids have a variety of functions, including stimulation of homeostatic responses in the cardiovascular system, induction and resolution of inflammation, and modulation of immune responses against diseases associated with chronic inflammation, such as cancer. Because chronic inflammation is essential for the development of colorectal cancer (CRC), it is not surprising that many eicosanoids are implicated in CRC. Oftentimes, these autacoids work in an antagonistic and highly temporal manner in inflammation; therefore, inhibition of the pro-inflammatory COX-2 or 5-LOX enzymes may subsequently inhibit the formation of their essential products, or shunt substrates from one pathway to another, leading to undesirable side-effects. A better understanding of these different enzymes and their products is essential not only for understanding the importance of eicosanoids, but also for designing more effective drugs that solely target the inflammatory molecules found in both chronic inflammation and cancer. In this review, we have evaluated the cancer promoting and anti-cancer roles of different eicosanoids in CRC, and highlighted the most recent literature which describes how those molecules affect not only tumor tissue, but also the tumor microenvironment. Additionally, we have attempted to delineate the roles that eicosanoids with opposing functions play in neoplastic transformation in CRC through their effects on proliferation, apoptosis, motility, metastasis, and angiogenesis.

Developmental regulation and induction of cytochrome P450 2W1, an enzyme expressed in colon tumors

Cytochrome P450 2W1 (CYP2W1) is expressed predominantly in colorectal and also in hepatic tumors, whereas the levels are insignificant in the corresponding normal human adult tissues. CYP2W1 has been proposed as an attractive target for colorectal cancer (CRC) therapy by exploiting its ability to activate duocarmycin prodrugs to cytotoxic metabolites. However, its endogenous function, regulation and developmental pattern of expression remain unexplored. Here we report the CYP2W1 developmental expression in the murine and human gastrointestinal tissues. The gene expression in the colon and small intestine commence at early stages of embryonic life and is completely silenced shortly after the birth. Immunohistochemical analysis of human fetal colon revealed that CYP2W1 expression is restricted to the crypt cells. The silencing of CYP2W1 after birth correlates with the increased methylation of CpG-rich regions in both murine and human CYP2W1 genes. Analysis of CYP2W1 expression in the colon adenocarcinoma cell line HCC2998 revealed that the gene expression can be induced by e.g. the antitumor agent imatinib, linoleic acid and its derivatives. The imatinib mediated induction of CYP2W1 suggests an adjuvant therapy to treatment with duocarmycins that thus would involve induction of tumor CYP2W1 levels followed by the CYP2W1 activated duocarmycin prodrugs. Taken together these data strongly support further exploration of CYP2W1 as a specific drug target in CRC.

RacGAP1 expression, increasing tumor malignant potential, as a predictive biomarker for lymph node metastasis and poor prognosis in colorectal cancer

Rac GTPase-activating protein (RacGAP) 1 plays a key role in controlling various cellular phenomena including cytokinesis, transformation, invasive migration and metastasis. This study investigated the function and clinical significance of RacGAP1 expression in colorectal cancer (CRC). The intrinsic functions of RacGAP1 in CRC cells were analyzed using small interfering RNA (siRNA). We analyzed RacGAP1 mRNA expression in surgical specimens from 193 CRC patients (Cohort 1) by real-time PCR. Finally, we validated RacGAP1 protein expression using formalin-fixed paraffin-embedded samples from 298 CRC patients (Cohort 2) by immunohistochemistry. Reduced RacGAP1 expression by siRNA in CRC cell lines showed significantly decreased cellular proliferation, migration and invasion. In Cohort 1, RacGAP1 expression in CRC was significantly higher than in adjacent normal mucosa and increased according to tumor node metastasis stage progression. High RacGAP1 expression in tumors was significantly associated with progression and prognosis. In Cohort 2, RacGAP1 protein was overexpressed mainly in the nuclei of CRC cells; however, its expression was scarcely observed in normal colorectal mucosa. RacGAP1 protein expression was significantly higher in CRC patients with higher T stage, vessel invasion and lymph node and distant metastasis. Increased expression of RacGAP1 protein was significantly associated with poor disease-free and overall survival. Multivariate analyses revealed that high RacGAP1 expression was an independent predictive marker for lymph node metastasis, recurrence and poor prognosis in CRC. Our data provide novel evidence for the biological and clinical significance of RacGAP1 as a potential biomarker for identifying patients with lymph node metastasis and poor prognosis in CRC.

Establishing a biological profile for interval colorectal cancers

Colorectal cancer (CRC) remains the second leading cause of cancer-related deaths in North America. Screening for CRC and its precursor lesions is highly effective in reducing the incidence and deaths due to the disease. However, there remain a substantial number of individuals who are diagnosed with CRC soon after a negative/clearing colonoscopy with no documented evidence of CRC. The occurrence of these interval CRCs (I-CRCs) reduces the effectiveness of CRC screening and detection tests and has only recently attracted wide spread attention. I-CRCs can be subdivided into those that occur most likely due to the failure of the colonoscopy examination (missed CRC and CRC that developed from missed or incompletely resected precursor lesions) and those that develop rapidly after the colonoscopy (de novo I-CRCs). In this review, we discuss the current literature and present both the clinical and biological factors that have been identified to account for I-CRCs, with a particular focus on the aberrant molecular features that are candidate causative agents for I-CRCs. We conclude additional studies are required to fully understand the molecular features that lead to the development of I-CRCs, which in turn is essential to develop measures to prevent the occurrence of this group of CRCs and thereby improve CRC screening and detection strategies.

Polymorphisms in RETN gene and susceptibility to colon cancer in Saudi patients

BACKGROUND AND OBJECTIVES

Resistin is an adipocytokine, which has been studied for its role in insulin resistance and recently in inflammation. Several single-nucleotide polymorphisms (SNPs) have been identified in the human resistin gene (RETN). This study aims to investigate the association of RETN rs1862513 (C-420G) and rs3745367 (G+299A) SNPs with the colon cancer risk in Saudi patients.

DESIGN AND SETTING

This is a case-control study conducted among Saudi adult colon cancer patients recruited from King Abdulaziz Hospital and Oncology Center in Jeddah, Saudi Arabia.

SUBJECTS AND METHODS

In this study, 120 Saudi volunteers (60 colon cancer patients and 60 disease-free controls) were studied. The SNPs were determined by polymerase chain reaction (PCR) and genotyping using PCR- restriction fragment length polymorphism analysis.

RESULTS

In comparing the result obtained for the patient group with that of the controls, colon cancer group displayed different genotype distribution of the RETN C-420G and G+299A SNPs. The study indicated that the SNP-420 heterozygous (CG) genotype (odds ratio [OR]=2.48, 95% CI 1.07-5.74, P=.03) and the SNP +299 heterozygous (GA) genotype (OR=6.5, 95% CI 1.77-24.18, P=.002) significantly increased the risk of colon cancer. A further analysis of the genotype combination of SNPs RETN C-420G and G+299A showed a larger increase in the colon cancer risk.

CONCLUSION

These preliminary results suggested a potential role for RETN C-420G and G+299A polymorphisms in the genetic predisposition to colon cancer disease.

Overexpression of integrin-linked kinase (ILK) promotes migration and invasion of colorectal cancer cells by inducing epithelial-mesenchymal transition via NF-κB signaling

Integrin-linked kinase (ILK), a ubiquitously expressed and evolutionally conserved serine/threonine kinase, has been shown to be aberrantly overexpressed and activated in diversified types of human malignancies, including colorectal cancer (CRC). However, the potential role of ILK in cancer cell migration and invasion remains to be elucidated. In this study, we introduced the human ILK gene into a low ILK-expressing human CRC cell line SW480. Cell migration and invasion were evaluated by the wound healing assay and transwell invasion assay, respectively. The epithelial-mesenchymal transition (EMT)-related proteins were detected by Western blot analysis or immunofluorescence. We found that enforced overexpression of ILK in SW480 cells dramatically promoted their migratory and invasive ability in vitro. Furthermore, SW480 cells stably overexpressing ILK underwent EMT, as indicated by mesenchymal morphology, decreased expression of E-cadherin, and increased expression of vimentin, Snail, and Slug. Finally, the nuclear factor (NF)-κB inhibitor BAY 11-7028 or NF-κB p65 small interfering RNA significantly restored the reduced E-cadherin level in ILK-overexpressing cells, suggesting that ILK-mediated down-regulation of E-cadherin is dependent on NF-κB activation. Overall, our study demonstrates a pivotal role of ILK in EMT and metastasis, and suggests novel therapeutic opportunities for the treatment of CRC.

Dihydroartemisinin induces apoptosis in colorectal cancer cells through the mitochondria-dependent pathway

Dihydroartemisinin (DHA), a semisynthetic derivative of artemisinin isolated from the traditional Chinese herb Artemisia annua, has been shown to exhibit antitumor activity in various cancer cells, including colorectal cancer. However, the detailed mechanisms underlying its antitumor activity in colorectal cancer remain to be elucidated. In the present study, we investigated DHA-induced apoptosis in human colorectal cancer HCT-116 cells in vitro. The results showed that DHA treatment significantly reduced cell viability in a concentration- and time-dependent manner. Furthermore, DHA induced G1 cell cycle arrest, apoptotic cell death, and accumulation of reactive oxygen species (ROS). We also found that DHA decreased the mitochondrial membrane potential; activated the caspase-3, caspase-8, and caspase-9; and increased the ratio of Bax/Bcl-2. Meanwhile, the translocation of apoptotic inducing factor (AIF) and the release of cytochrome c from the mitochondria were observed. Strikingly, the free radical scavenger N-acetylcysteine or the caspase-3 inhibitor Ac-DEVD-CHO significantly prevented DHA-induced apoptotic cell death. Taken together, we concluded that DHA-triggered apoptosis in HCT-116 cells occurs through the ROS-mediated mitochondria-dependent pathway. Our data suggest that DHA has great potential to be developed as a novel therapeutic agent for the treatment of human colorectal cancer.

Molecular profiling in colorectal cancer: current state of play and future directions

SUMMARY In the era of molecular scientific discovery, there is a continuing gap between our growing scientific knowledge and its utility at the bedside. This phenomenon probably occurs more frequently in colorectal cancer than in other cancer streams, with thousands of scientific studies having produced only a handful of molecular interventions. This review examines our current practices of molecular profiling in colorectal cancer and the scientific research that may impact on this area in the future.

Increased expression of Slug and Vimentin as novel predictive biomarkers for lymph node metastasis and poor prognosis in colorectal cancer

Slug and Vimentin genes play a critical role in regulating epithelial-mesenchymal transition (EMT) via downregulation of epithelial markers and upregulation of mesenchymal markers. The present study evaluated the clinical significance of Slug and Vimentin expression as potential disease biomarkers in colorectal cancer (CRC). At first, the biological role of Slug in CRC was assessed by RNA interference in CRC cell lines to assess tumor progression, invasion and migration. Next, we analyzed Slug and Vimentin expression in surgical tissue specimens from 181 CRC patients (Cohort 1) by quantitative real-time reverse transcription-PCR and 208 patients (Cohort 2) by immunohistochemistry. Knockdown of Slug using small interfering RNA in CRC cell lines resulted in inhibition of EMT, reduced cell proliferation, invasion and migration in CRC cells. Interestingly, Slug and Vimentin expression in cancer tissues was significantly higher in patients with higher T stage, lymph node involvement, liver metastasis and advanced tumor node metastasis stages. A significant correlation was observed between Slug and Vimentin expression in CRC (messenger RNA: ρ = 0.546, protein: ρ = 0.405), and increased expression of Slug and Vimentin was significantly associated with poor prognosis. Furthermore, increased expression of Slug emerged as an independent prognostic factor and a predictive marker of lymph node metastasis in CRC patients. Our data provide novel evidence for the biological and clinical significance of Slug and Vimentin expression as potential predictive biomarkers for identifying patients with lymph node metastasis or poor prognosis in CRC.

NDST4 is a novel candidate tumor suppressor gene at chromosome 4q26 and its genetic loss predicts adverse prognosis in colorectal cancer

Background

Genomic deletion at tumor suppressor loci is a common genetic aberration in human cancers. The study aimed to explore candidate tumor suppressor genes at chromosome 4q25-q28.2 and to delineate novel prognostic biomarkers associated with colorectal cancer (CRC).

Methods

Deletion mapping of chromosome 4q25-q28.2 was conducted in 114 sporadic CRC by loss of heterozygosity study with 11 microsatellite markers. A novel candidate tumor suppressor gene, namely NDST4, was identified at 4q26. Gene expression of NDST4 was investigated in 52 pairs of primary CRC tissues by quantitative reverse transcription-polymerase chain reaction. Allelic loss of NDST4 gene was further determined in 174 colorectal carcinomas by loss of heterozygosity analysis, and then was assessed for clinical relevance.

Results

One minimal deletion region was delineated between D4S2297 and D4S2303 loci at 4q26, where NDST4 was the only gene that had markedly been downregulated in CRC tumors. By laser capture microdissection, NDST4 RNA expression was demonstrated in colonic epithelial cells, but was undetectable in tumor cells. In total, 30 (57.7%) of 52 colorectal carcinomas showed a dramatic reduction in NDST4 gene expression compared with matched normal mucosae. The genetic loss of NDST4 was significantly associated with advanced pathological stage (P = 0.039) and poorer overall survival of patients (P = 0.036).

Conclusions

NDST4 gene is a novel candidate tumor suppressor gene in human cancer, and the loss of its function might be involved in CRC progression. In addition, the loss of heterozygosity assay, which was established to determine the allelic loss of NDST4 gene, could be a cost-effective tool for providing a useful biomarker of adverse prognosis in CRC.

ERCC1, defective mismatch repair status as predictive biomarkers of survival for stage III colon cancer patients receiving oxaliplatin-based adjuvant chemotherapy

Background:

Excision repair cross-complementation group 1 (ERCC1) expression status has been identified as a candidate marker for predicting efficacy of oxaliplatin (OX) treatment for metastatic colorectal cancer (CRC) in several trials. Also, an association between expression of mismatch repair (MMR) genes and favourable postoperative survival in stage II CRC receiving 5-FU chemotherapy has been identified. It is unknown if the expression of ERCC1 protein and MMR status are associated with survival of stage III colon cancer receiving OX-based chemotherapy.

Methods:

Immunohistochemistry (IHC) analysis of the expression of MMR and ERCC1 was performed on tumour tissue of 255 patients with stage III colon cancer. In all, 95 patients received fluoropyrimidine-based chemotherapy and 160 patients received OX-based chemotherapy. A predictive model for 5-year disease-free survival (DFS) and overall survival (OS) was constructed using Kaplan–Meier analysis, logistic and Cox regression.

Results:

Patients who were treated with OX-based therapy with positive ERCC1 tumours had lower 5-year DFS (54%) and OS (60%) than those with negative ERCC1 tumours (72% and 78%, respectively; DFS HR: 1.98, 95% confidence interval (CI): 1.19–3.31, P=0.009; OS HR: 2.44, 95% CI: 1.37–4.34, P=0.02). Excision repair cross-complementation group 1 status did not impact DFS or OS in fluorouracil group (DFS HR: 1.16, 95% CI: 0.63–2.14, P=0.62; OS HR: 1.16, 95% CI: 0.63–2.14, P=0.63), whereas MMR status had no impact on DFS or OS in either group.

Conclusion:

Excision repair cross-complementation group 1 status is highly predictive of which patients will benefit from the addition of OX to 5-FU for stage III colon cancer. Mismatch repair status had no predictive value in this setting.

Recent approaches to identifying biomarkers for high-risk stage II colon cancer

The use of adjuvant chemotherapy for stage II colon cancer remains controversial. The accurate assessment of the risk factors associated with recurrence in patients with stage II disease is the key to identifying the patients that are most likely to benefit from adjuvant chemotherapy. Recent guidelines advocate that adjuvant chemotherapy for high-risk stage II colon cancer should take into account factors such as the T stage, number of lymph nodes examined, tumor differentiation, and tumor perforation. In addition to these clinicopathological factors, there has also been intense interest in the identification of new prognostic or predictive biomarkers that can improve outcomes through better patient classification and selection for adjuvant chemotherapy. Recent advances in the field of molecular genetics have led to the identification of specific biomarkers involved in colorectal cancer progression, whereas gene expression microarray technology has led to the identification of molecular profiles able to predict recurrence or benefit from adjuvant chemotherapy. However, none of these has yet been validated in large prospective clinical trials. In this article, we review the current status of prognostic and predictive biomarkers for stage II colon cancer and provide an update on the most recent developments.

Discriminant function based on parameters of hyaluronic acid metabolism and nitric oxide to differentiate metastatic from non-metastatic colorectal cancer patients

Colorectal cancer (CRC) is one of the most common causes of cancer-related deaths worldwide. Because there is currently no useful serological marker for metastatic colorectal cancer, the search for simple biomarkers for colorectal cancer diagnosis and prognosis is needed. Hyaluronic acid level was determined by ELISA; in addition to its degrading enzymes, degradation products and nitric oxide were determined by standard techniques in 185 CRC patients with and without metastases. Statistical analyses were performed by logistic regression and receiver-operating characteristic (ROC) curves. The multivariate discriminate analysis (MDA) selects a function based on absolute values of six biochemical markers; score = [-0.62 (numerical constant) + hyaluronic acid (pg/l) × 0.002 + hyaluronidase (mg N-acetyl glucosamine/ml/18 h) × 0.009-β-glucuronidase (μmol/ml/min) × 0.07 + N-acetyl-β-D-glucosaminidase (μmol/ml/min) × 0.019-glucuronic acid (μg/dl) × 0.001 + nitric oxide (μmol/l) × 0.01]. The selected MDA function correctly classified 92% of the metastatic CRC patients at a discriminate cut-off score = 0.24 (i.e., less than 0.24 indicated patients with non-metastatic colon cancer, and greater than 0.24 indicated patients with metastatic colon cancer with high degrees of sensitivity (100%) and specificity (93%)). The positive predictive and negative predictive values were also high (81% and 85%, respectively). Colorectal cancer patients can be simply and efficiently classified into metastatic or non-metastatic using their MDA score.

Soluble CXCL16 in preoperative serum is a novel prognostic marker and predicts recurrence of liver metastases in colorectal cancer patients

PURPOSE

This study was designed to identify novel and reliable serum prognostic markers in patients with colorectal cancer (CRC).

METHODS

Based on cytokine array analysis, we identified soluble CXCL16 as a novel prognostic serum marker. Serum levels of CXCL16 were assessed in 314 CRC patients and 20 normal volunteers by enzyme-linked immunosorbent assay, and their relationships with clinicopathologic findings, including survival, were investigated. Proliferation, invasion, and wound healing assays were used to investigate the biological role of soluble CXCL16 in CRC cells, by exposure of HT-29 cells to recombinant CXCL16.

RESULTS

The median serum CXCL16 concentration in CRC patients was significantly higher than that in normal volunteers. In addition, serum CXCL16 levels increased significantly in accordance with the progression of UICC stage classification. Elevated serum CXCL16 level was significantly associated with poor survival and was an independent prognostic marker in CRC patients. Furthermore, in stage I-III CRC patients who underwent curative intent surgery, elevated serum CXCL16 levels were significantly associated with metachronous liver recurrence and poor survival. Recombinant soluble CXCL16 promoted the epithelial-mesenchymal transition (EMT) phenotype characterized by impaired E-cadherin production and induction of vimentin in vitro. In addition, recombinant soluble CXCL16 promoted cell growth, migration, and invasion in a CRC cell line.

CONCLUSIONS

In this study, we identified CXCL16 as a novel prognostic marker. Preoperative high serum levels of CXCL16 were associated with metachronous liver recurrence and poor prognosis in CRC patients. Soluble CXCL16 may play an important role in liver metastases through the induction of EMT.

Adjuvant Chemotherapy for Stage II Colon Cancer: The Role of Molecular Markers in Choosing Therapy

The optimal adjuvant treatment for stage II colon cancer remains controversial. While chemotherapy is often recommended for high-risk stage II disease, many low-grade tumors with similar histopathologic features will recur and ultimately cause cancer-associated mortality. The development of molecular markers that predict clinical outcome or response to therapy in stage II colon cancer is an important tool that could give clinicians added information in discussions regarding the role of adjuvant chemotherapy. While many potential molecular biomarkers have been investigated, to date none have been validated in prospective clinical trials. Among the most promising molecular markers to be studied are microsatellite instability and 18q and 17p loss of heterozygosity, both of which are currently being evaluated as prognostic indicators in a large prospective clinical trial (Eastern Cooperative Oncology Group 5202). This review focuses on potential molecular biomarkers being evaluated for their prognostic value in stage II colon cancer and their potential role in clinical decision-making regarding the use of adjuvant chemotherapy.

Genetics, cytogenetics, and epigenetics of colorectal cancer

Most of the colorectal cancer (CRC) cases are sporadic, only 25% of the patients have a family history of the disease, and major genes causing syndromes predisposing to CRC only account for 5-6% of the total cases. The following subtypes can be recognized: MIN (microsatellite instability), CIN (chromosomal instability), and CIMP (CpG island methylator phenotype). CIN occurs in 80-85% of CRC. Chromosomal instability proceeds through two major mechanisms, missegregation that results in aneuploidy through the gain or loss of whole chromosomes, and unbalanced structural rearrangements that lead to the loss and/or gain of chromosomal regions. The loss of heterozygosity that occur in the first phases of the CRC cancerogenesis (in particular for the genes on 18q) as well as the alteration of methylation pattern of multiple key genes can drive the development of colorectal cancer by facilitating the acquisition of multiple tumor-associated mutations and the instability phenotype.

Immunotherapy for treating metastatic colorectal cancer

BACKGROUND

Colorectal cancer remains one of the leading causes of death in the world. Surgery still remains the mainstay of treatment for primary and metastatic colorectal cancer. Immunotherapy used as an adjunct to surgery can play an important role in controlling the spread of tumour.

METHODS

The online databases PubMed, Medline, Scirus and Medscape Oncology were used to identify articles of relevance. Keywords included; "Immunotherapy", "Cellular Immunotherapy", "Metastatic Colorectal Cancer", "Monoclonal Antibody" "Tumour Vaccines" and "Adoptive Cell Therapy". The databases search was from the period of June 1995 until May 2010 inclusive.

RESULTS

Our understanding of tumour immunology has allowed the development of some successful therapies. Immunotherapy through the use of monoclonal antibodies is an effective adjunct to chemotherapy for metastatic colorectal cancer. Other modalities that are in the stages of development are cellular and conjugated vaccines. However, these vaccines are being experimented in advanced stages of colorectal tumours.

CONCLUSION

Colorectal cancer vaccines are being developed for advanced stages of colorectal tumour. However, their use as an early adjunct could potentially limit the spread of tumour or even result in cure. Further trials are required to ensure the safety and efficacy of cellular vaccines against colorectal tumours to allow their use on patients early in their disease presentation.

A review of the most promising biomarkers in colorectal cancer: one step closer to targeted therapy

Rapidly growing insights into the molecular biology of colorectal cancer (CRC) and recent developments in gene sequencing and molecular diagnostics have led to high expectations for the identification of molecular markers to be used in optimized and tailored treatment regimens. However, many of the published data on molecular biomarkers are contradictory in their findings and the current reality is that no molecular marker, other than the KRAS gene in the case of epidermal growth factor receptor (EGFR)- targeted therapy for metastatic disease, has made it into clinical practice. Many markers investigated suffer from technical shortcomings, resulting from lack of quantitative techniques to capture the impact of the molecular alteration. This understanding has recently led to the more comprehensive approaches of global gene expression profiling or genome-wide analysis to determine prognostic and predictive signatures in tumors. In this review, an update of the most recent data on promising biological prognostic and/or predictive markers, including microsatellite instability, epidermal growth factor receptor, KRAS, BRAF, CpG island methylator phenotype, cytotoxic T lymphocytes, forkhead box P3-positive T cells, receptor for hyaluronic acid-mediated motility, phosphatase and tensin homolog, and T-cell originated protein kinase, in patients with CRC is provided.

Tumor infiltrating lymphocytes: an intriguing player in the survival of colorectal cancer patients

Background

There is growing evidence that both local and systemic inflammatory responses play an important role in the progression of a variety of solid tumors. Colorectal cancer results from the cumulative effect of sequential genetic alterations, leading to the expression of tumor associated antigens possibly inducing a cellular anti-tumor immune response. It is well recognized that cytotoxic lymphocytes constitute one of the most important effector mechanisms of anti-tumor-immunity. However, their potential prognostic influence in colorectal cancer remains controversial. Aim of the study was to examine infiltration of CD3⁺ and CD8⁺ lymphocytes in colorectal cancer and their prognostic potential.

Two-hundred-fifteen colorectal cancer cases, previously analyzed for microsatellite instability (MSI), were selected for immunohistochemical detection of CD3⁺, CD8⁺ infiltration and the expression of granzyme B. Prognostic relevance was assessed by survival analysis.

Results

Strong correlations were found between the infiltration of lymphocytes and several clinicopathological variables. Survival analysis revealed that intra-epithelial infiltration of CD3⁺ and CD8⁺ T lymphocytes and stromal infiltration of CD3⁺ lymphocytes had a major impact on the patients' overall survival in the univariate analysis, however independent of their association with MSI-status. In addition, it was also demonstrated that there was an important disease specific survival advantage for patients with microsatellite stable (MSS) tumors containing intraepithelial CD8⁺ tumor infiltrating lymphocytes. When samples were analyzed for colon cancer and rectal cancer separately, the results of the overall population were confirmed in colon cancer only. When entered into a multiple Cox regression analysis adjusting for other possible important confounding factors, the strong impact of lymphocyte infiltration on overall survival was not maintained. Only early stage and young age (borderline significant for overall population only) were associated with a better overall survival (early disease with disease-free survival also).

Conclusions

In conclusion our results suggest a role for infiltrating CD3⁺ and CD8⁺ T lymphocytes in colorectal cancer whereby tumor infiltration could reflect a general principle of antitumor immunity, irrespective of the MSI-status.

Serum cellular apoptosis susceptibility protein is a potential prognostic marker for metastatic colorectal cancer

Colorectal cancer has high rates of recurrence and metastasis. Many patients with similar histopathological features show significantly different clinical outcomes, and these differences are primarily related to metastases undetected by current diagnostic methods. There is no useful serological marker for metastatic disease. We investigated the cellular apoptosis susceptibility (CSE1L/CAS) protein in comparison with carcinoembryonic antigen (CEA) as a marker for metastatic colorectal cancer. Using serum from 103 patients with stage I, II, III, and IV disease, CSE1L was detected in 36.0% (9 of 25), 57.7% (15 of 26), 71.4% (30 of 42), and 88.9% (8 of 9) of patients, respectively; a pathological CEA level was found in 16.0% (4 of 25), 42.3% (11 of 26), 47.6% (20 of 42), and 77.8% (7 of 9) of patients, respectively; a combined CSE1L/CEA assay was detected in 48.0% (12 of 25), 65.4% (17 of 26), 88.1% (37 of 42), and 100% (9 of 9) of patients, respectively. Lymphatic metastasis is an important predictor of poor prognosis and crucial for determination of therapeutic strategy. Serum CSE1L was detected in 74.5% (38 of 51) of patients with lymph node metastasis, whereas a pathological CEA level was found in only 52.9% (27 of 51) of the same patients (P < 0.001); the combined CSE1L/CEA assay increased sensitivity to 90.2% (46 of 51). Animal experiments showed CSE1L reduction in B16-F10 melanoma cells correlated with decreased metastasis to the colorectal tract in C57BL/6 mice. These results indicate that assay of serum CSE1L may facilitate diagnosis of colorectal cancer lymphatic metastases; furthermore, CSE1L is a possible therapeutic target.

Circulating tumor cells in gastrointestinal malignancies: current techniques and clinical implications

Since their introduction more than 50 years by Engell, circulating tumor cells (CTCs) have been evaluated in cancer patients and their detection has been correlated with clinical outcome, in esophageal, gastric, and colorectal cancer. With the availability of refined technologies, the identification of CTCs from peripheral blood is emerging as a useful tool for the detection of malignancy, monitoring disease progression, and measuring response to therapy. However, increasing evidence suggests a variety of factors to be responsible for disease progression. The analysis of a single CTC marker is therefore unlikely to accurately predict progression of disease with sufficient resolution and reproducibility. Here we discuss the current concept of CTCs, summarize the available techniques for their detection and characterization, and aim to provide a comprehensive update on the clinical implications of CTCs in gastrointestinal (GI) malignancies.

Tissue biomarker development in a multicentre trial context: a feasibility study on the PETACC3 stage II and III colon cancer adjuvant treatment trial

PURPOSE

We evaluated the feasibility of biomarker development in the context of multicenter clinical trials.

EXPERIMENTAL DESIGN

Formalin-fixed, paraffin-embedded (FFPE) tissue samples were collected from a prospective adjuvant colon cancer trial (PETACC3). DNA was isolated from tumor as well as normal tissue and used for analysis of microsatellite instability, KRAS and BRAF genotyping, UGT1A1 genotyping, and loss of heterozygosity of 18 q loci. Immunohistochemistry was used to test expression of TERT, SMAD4, p53, and TYMS. Messenger RNA was retrieved and tested for use in expression profiling experiments.

RESULTS

Of the 3,278 patients entered in the study, FFPE blocks were obtained from 1,564 patients coming from 368 different centers in 31 countries. In over 95% of the samples, genomic DNA tests yielded a reliable result. Of the immmunohistochemical tests, p53 and SMAD4 staining did best with reliable results in over 85% of the cases. TERT was the most problematic test with 46% of failures, mostly due to insufficient tissue processing quality. Good quality mRNA was obtained, usable in expression profiling experiments.

CONCLUSIONS

Prospective clinical trials can be used as framework for biomarker development using routinely processed FFPE tissues. Our results support the notion that as a rule, translational studies based on FFPE should be included in prospective clinical trials.

Polymorphisms in interleukin 1 beta and interleukin 1 receptor antagonist associated with tumor recurrence in stage II colon cancer

PURPOSE

Identifying molecular markers for tumor recurrence is critical in successfully selecting patients with stage II colon cancer who are more likely to benefit from adjuvant chemotherapy. Interleukin 1 beta (IL1B) and interleukin 1 receptor antagonist (IL1RN) have been shown to play a critical role in the early onset of tumor-associated angiogenesis. In this study, we tested whether eight functionally significant polymorphisms within six genes of the angiogenesis pathway [IL1B, IL1RN, vascular endothelial growth factor A (VEGFA), VEGF receptor 2, interleukin-8, cyclooxygenase-2] will predict the risk of tumor recurrence in stage II colon cancer patients treated with 5-fluorouracil based adjuvant chemotherapy.

EXPERIMENTAL DESIGN

Blood samples were obtained from 109 patients with stage II colon cancer at the University of Southern California medical facilities. DNA was extracted from peripheral blood and the genotypes were analyzed using PCR-restriction fragment length polymorphism protocols.

RESULTS

Patients harboring the IL1RN/IL1B 1-T-C (IL-1RN variable number tandem repeats (VNTR)/IL1B C+3954T/C-511T) haplotype were at greatest risk of developing tumor recurrence [relative risk (RR): 2.72, 95% confidence interval (CI): 1.22-6.08] (adjusted P=0.015). In addition, IL1B +3954 any T (RR: 2.78, 95% CI: 0.99-7.83) (adjusted P=0.043), IL1RN VNTR (RR: 6.09, 95% CI: 1.11-33.4) (adjusted P=0.038), and VEGFA -634 any C (RR: 2.91, 95% CI: 1.13-7.48) (adjusted P=0.026) were shown to be adverse prognostic markers, in both univariate and multivariable analyses.

CONCLUSION

Polymorphisms in IL1B, IL1RN, and VEGFA as well as IL1B/IL1RN haplotype analysis may serve as molecular markers for tumor recurrence in stage II colon cancer, indicating that the analysis of angiogenesis-related gene polymorphisms may help to identify patient subgroups at high risk for tumor recurrence.

Overall expression of beta-catenin outperforms its nuclear accumulation in predicting outcomes of colorectal cancers

AIM

To examine the expression of beta-catenin in colorectal cancer and look for association with other clinico-pathological parameters.

METHODS

Tumor samples from 163 cases of colorectal cancer (CRC) who had undergone primary colectomy between May, 1998 and November, 2002 with complete follow-up data for either 5 years or until death were recruited for a beta-catenin immunohistochemical study. The percentage of immunoreacted tumor cells was defined as overall staining density (OSD) and percentage of cells having nuclear localization was counted as nuclear staining density (NSD). Univariate exploration used log-rank test and multivariate survival analysis used Cox's hazard regression model.

RESULTS

Beta-catenin immunoreactivity was detected in 161 samples (98.8%), of which 131 cases had nuclear staining. High OSD (> or = 75%), detected in 123 cases (75.5%), was significantly associated with earlier clinical staging (P < 0.01), lower nodal status (P = 0.02), non-metastatic status (P < 0.01) and better differentiation (P = 0.02). Multivariate analysis found that high OSD was independently associated with better survival [Cox's hazard ratio 0.51, 95% confidence interval (CI) 0.31-0.83]. Although high NSD (> or = 75%) was correlated with high pre-operative serum CEA (P = 0.03), well differentiation (P < 0.01), and increased staining intensity (P < 0.01), the parameter was not significantly associated with survival.

CONCLUSION

Unlike previous reports, the study did not find a predictive value of nuclear beta-catenin in CRC. Instead, the overall expression of beta-catenin in CRC showed an association with better differentiation and earlier staging. Moreover, the parameter also independently predicted superior survival.

Systemic treatment of colorectal cancer

Colorectal cancer is the fourth most common noncutaneous malignancy in the United States and the second most frequent cause of cancer-related death. Over the past 12 years, significant progress has been made in the systemic treatment of this malignant condition. Six new chemotherapeutic agents have been introduced, increasing median overall survival for patients with metastatic colorectal cancer from less than 9 months with no treatment to approximately 24 months. For patients with stage III (lymph node positive) colon cancer, an overall survival benefit for fluorouracil-based chemotherapy has been firmly established, and recent data have shown further efficacy for the inclusion of oxaliplatin in such adjuvant treatment programs. For patients with stage II colon cancer, the use of adjuvant chemotherapy remains controversial, but may be appropriate in a subset of individuals at higher risk for disease recurrence. Ongoing randomized clinical trials are evaluating how best to combine currently available therapies, while smaller studies are evaluating new agents, with the goal of continued progress in prolonging life among patients with metastatic colorectal cancer and increasing cure rates among those with resectable disease.