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Colorectal cancer (CRC) is one of the most common cancers and is the second leading cause of cancer-related death in the world. Due to the westernization of diets, young patients with CRC are often diagnosed at advanced stages with an associated poor prognosis. Improved lifestyle choices are one way to minimize CRC risk. Among diet choices is the inclusion of bee propolis, long recognized as a health supplement with anticancer activities. Understanding the effect of propolis on the gut environment is worth exploring, and especially its associated intratumoral immune changes and its anticancer effect on the occurrence and development of CRC. In this study, early stage CRC was induced with 1,2-dimethylhydrazine (DMH) and dextran sulfate sodium (DSS) for one month in an animal model, without and with propolis administration. The phenotypes of early stage CRC were evaluated by X-ray microcomputed tomography and histologic examination. The gut immunity of the tumor microenvironment was assessed by immunohistochemical staining for tumor-infiltrating lymphocytes (TILs) and further comparative quantification. We found that the characteristics of the CRC mice, including the body weight, tumor loading, and tumor dimensions, were significantly changed due to propolis administration. With further propolis administration, the CRC tissues of DMH/DSS-treated mice showed decreased cytokeratin 20 levels, a marker for intestinal epithelium differentiation. Additionally, the signal intensity and density of CD3 + and CD4 + TILs were significantly increased and fewer forkhead box protein P3 (FOXP3) lymphocytes were observed in the lamina propria. In conclusion, we found that propolis, a natural supplement, potentially prevented CRC progression by increasing CD3 + and CD4 + TILs and reducing FOXP3 lymphocytes in the tumor microenvironment of early stage CRC. Our study could suggest a promising role for propolis in complementary medicine as a food supplement to decrease or prevent CRC progression.

The chromosome segregation 1‑like (CSE1L) protein, which regulates cellular mitosis and apoptosis, was previously found to be overexpressed in colorectal cancer (CRC) cells harboring mutations. Therefore, regulating CSE1L expression may confer chemotherapeutic effects against CRC. The gut microflora can regulate gene expression in colonic cells. In particular, metabolites produced by the gut microflora, including the short‑chain fatty acid butyrate, have been shown to reduce CRC risk. Butyrates may exert antioncogenic potential in CRC cells by modulating p53 expression. The present study evaluated the association between CSE1L expression and butyrate treatment from two non‑transformed colon cell lines (CCD‑18Co and FHC) and six CRC cell lines (LS 174T, HCT116 p53 +/+ , HCT116 p53 ‑/‑ , Caco‑2, SW480 and SW620). Lentiviral knockdown of CSE1L and p53, reverse transcription‑quantitative PCR (CSE1L, c‑Myc and p53), western blotting [CSE1L, p53, cyclin (CCN) A2, CCNB2 and CCND1], wound healing assay (cell migration), flow cytometry (cell cycle analysis) and immunofluorescence staining (CSE1L and tubulin) were adopted to verify the effects of butyrate on CSE1L‑expressing CRC cells. The butyrate‑producing gut bacteria Butyricicoccus pullicaecorum was administered to mice with 1,2‑dimethylhydrazine‑induced colon tumors before the measurement of CSE1L expression. The effects of B. pullicaecorum on CSE1L expression were then assessed by immunohistochemical staining for CSE1L and p53 in tissues from CRC‑bearing mice. Non‑cancerous colon cells with the R273H p53 mutation or CRC cells haboring p53 mutations were found to exhibit significantly higher CSE1L expression levels. CSE1L knockdown in HCT116 p53 ‑/‑ cells resulted in G 1 ‑and G 2 /M‑phase cell cycle arrest. Furthermore, in HCT116 p53 ‑/‑ cells, CSE1L expression was already high at interphase, increased at prophase, peaked during metaphase before declining at cytokinesis but remained relatively high compared with that in HCT116 expressing wild‑type p53. Significantly decreased expression levels of CSE1L were also observed in HCT116 p53 ‑/‑ cells that were treated with butyrate for 24 h. In addition, the migration of HCT116 p53 ‑/‑ cells was significantly decreased after CSE1L knockdown or butyrate treatment. Tumors with more intense nuclear p53 staining and weaker CSE1L staining were found in mice bearing DMH/DSS‑induced CRC that were administered with B. pullicaecorum . Taken together, the results indicated that butyrate can impair CSE1L‑induced tumorigenic potential. In conclusion, butyrate‑producing microbes, such as B. pullicaecorum , may reverse the genetic distortion caused by p53 mutations in CRC by regulating CSE1L expression levels.

Background: The aim of the study was to enhance colorectal cancer prognostication by integrating single nucleotide polymorphism (SNP) and gene expression (GE) microarrays for genomic and transcriptional alteration detection; genes with concurrent gains and losses were used to develop a prognostic signature., Methods: The discovery dataset comprised 32 Taiwanese colorectal cancer patients, of which 31 were assayed for GE and copy number variations (CNVs) with Illumina Human HT-12 BeadChip v4.0 and Omni 25 BeadChip v1.1. Concurrent gains and losses were declared if coherent manners were observed between GE and SNP arrays. Concurrent genes were also identified in The Cancer Genome Atlas Project (TCGA) as the secondary discovery dataset (n = 345)., Results: The "universal" concurrent genes, which were the combination of z-transformed correlation coefficients, contained 4022 genes. Candidate genes were evaluated within each of the 10 public domain microarray datasets, and 1655 (2000 probe sets) were prognostic in at least one study. Consensus across all datasets was used to build a risk predictive model, while distinct relapse-free/overall survival patterns between defined risk groups were observed among four out of five training datasets. The predictive accuracy of recurrence, metastasis, or death was between 61 and 86% (cross-validation area under the receiver operating characteristic (ROC) curve: 0.548-0.833) from five independent validation studies., Conclusion: The colorectal cancer concurrent gene signature is prognostic in terms of recurrence, metastasis, or mortality among 1746 patients. Genes with coherent patterns between genomic and transcriptional contexts are more likely to provide prognostication for colorectal cancer., (© 2022. The Author(s).)

Dynein transport along the cytoskeletal microtubules towards the minus end is essential for cell division, cell migration and other basic cellular functions. Dynein cytoplasmic 1 light intermediate chain 1 (DYNC1LI1) has been previously associated with pancreatic ductal adenocarcinoma, hepatocellular carcinoma and prostate cancer. Cytoskeletal structures are involved in the regulation of the mucosal barrier integrity. Thus, improving our understanding of the molecular mechanisms that regulate the mucosal barrier is critical for cancer management and treatment. The present study aimed to investigate DYNC1LI1 expression in colorectal cancer (CRC) tissues. The American Joint Committee on Cancer Stage II CRC cell line LS 174T was used to determine the association between the cellular expression levels of DYNC1LI1 and different types of mucin (MUC) by reverse transcription‑quantitative PCR. The role of DYNC1LI1 in cell chemosensitivity and proliferation was also evaluated in the presence of the DNA analog 5‑fluorouracil (5‑FU) or the platinum‑based drug, oxaliplatin by the MTT assay. LS 174T cells with decreased expression levels of DYNC1LI1 were discovered to be more sensitive to 5‑FU compared with LS 174T cells with endogenous DYNC1LI1 expression levels. Moreover, LS 174T cells transfected with short hairpin RNA targeting DYNC1LI1 were associated with low MUC1 and high MUC2, MUC4 and MUC5AC expression levels. Notably, the CRC cells with low MUC1 expression levels and high expression levels of the other MUCs (MUC2, MU4 and MUC5AC) were shown to benefit from 5‑FU treatment. In conclusion, the findings of the present study have suggested that DYNC1LI1 expression may be significantly associated with MUC expression levels and may be used to predict the chemotherapeutic efficiency. However, additional functional studies and clinical reports are required for an improved understanding of the significance of these molecular interactions in tumorigenesis.

Peritoneal dissemination (PD) of cancer is difficult to diagnose. Previous reports have shown that carbohydrate antigen 125 (CA125) is a sensitive marker of PD of gastric cancer. However, CA125 has not been evaluated as a marker of colorectal cancer (CRC), and its accuracy in men is controversial. The aim of this study was to compare the ability of CA125 and carcinoembryonic antigen (CEA) to predict PD of CRC in men and women.Preoperative CA125 and CEA concentrations were measured in 853 people (510 men, 343 women) over 10 years. PD was confirmed intraoperatively in 57 patients. The predictive ability was compared between CA125 and CEA.Compared with CEA, CA125 concentration had a lower sensitivity, higher specificity, and diagnostic accuracy, and significantly greater area under the curve. Further analysis of CA125's sensitivity and specificity among CEA-negative group (n = 514) showed acceptable sensitivity (57.1%) and good specificity (92.0%). In men and women, CA125 concentration did not increase with stage from I to IV unless PD was present (P < 0.001). CEA concentration was increased in women with metastasis with PD (P < 0.001) or without PD (P < 0.001), but was increased only in men with metastasis without PD (P < 0.01). CA125 concentration correlated with PD grade for men and women, but CEA concentration correlated with grade only in women.When analyzed according to the primary tumor site, CA125 concentration in men did not differ between patients with the primary site in the right or left colon, or the rectum, regardless of PD status. By contrast, CA125 concentration differed between PD-positive and PD-negative patients with cancer in the right (P < 0.001) or left (P < 0.001) colon but not in the rectum. CEA concentration in men did not differ according to the primary site or PD status. In women, CA125 and CEA concentrations differed significantly between the PD-positive and PD-negative groups in patients with the primary tumor in the right (P < 0.001) or left (P < 0.001) colon; tumor sites did not differ between the PD-positive and PD-negative groups.These findings suggest that CA125 is a better tumor marker than CEA for predicting PD of CRC in both men and women., Competing Interests: The authors have no funding and conflicts of interest to disclose.

Colorectal cancer (CRC) is one of the most common life-threatening malignances worldwide. CRC relapse markedly decreases the 5-year survival of patients following surgery. Aberrant expression of genes involved in pathways regulating the cell cycle, cell proliferation, or cell death are frequently reported in CRC tumorigenesis. We hypothesized that genes involved in CRC relapse might serve as prognostic indicators. We first evaluated the significance of gene sequences in the feces of patients with CRC relapse by consulting a public database. Tumorigenesis of target tissues was tested through tumor cell growth, cell cycle regulation, and chemotherapeutic efficacy. We found a highly significant correlation between CRC relapse and growth arrest-specific 2 (GAS2) gene expression. Based on cell models, the overexpressed GAS2 was associated with cellular growth rate, cell cycle regulation, and with chemotherapeutic sensitivity. Cell division was impaired by treating cells with 2-[4-(7-chloro-2-quinoxalinyloxy)phenoxy]-propionic acid (XK469), even when the cells were overexpressing GAS2. Thus, downregulation of GAS2 expression might control CRC relapse after curative resection. GAS2 could serve as a noninvasive marker from the feces of patients with prediagnosed CRC. Our findings suggest that GAS2 could have potential clinical applications for predicting early CRC relapse after radical resection, and that XK469 might impair tumor cell division by reducing GAS2 expression or blocking its cellular translocation. This will help in selecting the best therapeutic option, 5-fluorouracil in combination with XK469, for patients overexpressing GAS2 in CRC cells. Thus, GAS2 might act as a prognostic biomolecule and potential therapeutic target in patients with CRC relapse., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Background: The development and progression of colorectal cancer (CRC) involve a complex process of multiple genetic changes. Tumor suppressor p53 is capable of determining the fate of CRC cells. However, the role of a p53-inducible modulator, ribosomal protein S27-like (RPS27L), in CRC is unknown., Methods: Here, the differential expression of RPS27L was examined in the feces and colonic tissues of CRC patients, to explore its possible correlation with patient survival and to investigate the cellular mechanisms underlying their clinical outcomes. Eighty intermediate-stage CRC patients (42 at stage II and 38 at stage III) were divided into two groups according to their fecal RPS27L mRNA levels. The survival probabilities of the groups were estimated using the Kaplan-Meier method. The RPS27L protein in the colonic tissues of stage III patients with different prognoses was further examined immunohistochemically. RPS27L expression in LoVo cells was manipulated to examine the possible cellular responses in vitro., Results: Elevated RPS27L expression, in either feces or tissues, was related to a better prognosis. In vitro, RPS27L-expressing LoVo cells ceased DNA synthesis and apoptotic activity while the expression of their DNA repair molecules was upregulated., Conclusions: Elevated RPS27L may improve the prognoses of certain CRC patients by enhancing the DNA repair capacity of their colonic cells, and can be determined in feces. By integrating clinical, molecular, and cellular data, our study demonstrates that fecal RPS27L may be a useful index for predicting prognoses and guiding personalized therapeutic strategies, especially in patients with intermediate-stage CRC.

Background: The liver is the most common target organ in the metastasis of colorectal cancer (CRC). Synchronous liver metastases may confer a poorer prognosis than metachronous metastases, and genetic alterations and an inflammatory response have also been associated with a poor prognosis in cases of a liver metastasis arising from CRC. However, few studies have examined the relationship between KRAS mutations and inflammatory status in CRC, especially with respect to liver metastases., Methods: The effect of the activated mitogen-activated protein kinase pathway and another protein involved in inflammation, C-reactive protein, in liver metastases were examined. We aimed to determine the impact of the CRP-specific single nucleotide polymorphism (SNP) rs7553007 in liver metastasis on the CRC-specific survival (CSS) of patients after colorectal liver metastasectomy., Results: We found no significant differences in genotype distributions and allele frequencies at the CRP SNP rs7553007 between CRC patients with liver metastasis and the control group. CSS rates were low in the subgroup of patients with synchronous metastasis with the A-allele (A/A and A/G) at rs7553007 or mutated KRAS/BRAF in liver metastatic specimens. Furthermore, the CRP SNP rs7553007 (hazard ratio [HR] = 1.101; 95% confidence interval [CI] = 1.011-1.200; P = 0.027) and KRAS/BRAF mutations (HR = 2.377; 95% CI = 1.293-4.368; P = 0.005) remained predictive for the CSS of CRC patients with synchronous liver metastasis in multivariate analysis., Conclusions: Both the CRP SNP rs7553007 and KRAS/BRAF mutations were independent prognostic factors for CRC patients with synchronous liver metastasis.

Background: An elevated plasma level of C-reactive protein (CRP) is a risk for, and prognostic factor of, colorectal cancer (CRC). In other reports of CRP concerning cardiovascular disease, CRP level correlated with its gene polymorphisms. We hypothesized that CRP polymorphisms associate risk and prognosis of CRC., Methods: This study enrolled 421 patients with CRC and 218 healthy control subjects. After preliminary studies, we selected four single nucleotide polymorphisms (SNPs) in the CRP gene: +2147A > G (rs1205), +942G > C (rs1800947), -717A > G (rs2794521), and -757T > C (rs3093059). At first, analyzing distributions of four SNPs between CRC case and non-CRC control groups was performed. Subsequently, the impacts of these SNPs with other prognostic factors of disease-free interval (DFI) and cancer-specific survival (CSS) were analyzed using uni- and multivariate Cox regression analyses., Results: The case and control groups differed in the frequency of -757T > C (P = 0.002). The CRC case group had a higher percentage of the TT genotype (odds, 1.75). Regarding prognoses, multivariate analyses revealed that four factors, including stage (I, II, III), gross tumor type (polypoid, ulcerative, infiltrative), location (right, left, rectum), and -757T > C SNP (odds, 1.29; P = 0.048), correlated with DFI; two factors, including stage and +2147A > G SNP (odds, 0.71; P = 0.03), correlated with CSS., Conclusions: The -757T > C SNP is a risk for and prognostic factor of DFI; the +2147A > G SNP is a prognostic factor of CSS. CRP polymorphisms associate the risk and survival of CRC.

Background: Colorectal cancer (CRC) is the predominant gastrointestinal malignancy and the leading cause of cancer death. The identification of genes related to CRC is important for the development of successful therapies and earlier diagnosis., Methods: Molecular analysis of feces was evaluated as a potential method for CRC detection. Expression of a predicted protein with unknown function, KIAA0247, was found in feces evaluated using specific quantitative real-time polymerase chain reaction. Its cellular function was then analyzed using immunofluorescent staining and the changes in the cell cycle in response to 5-fluorouracil (5-FU) were assessed., Results: Gastrointestinal tissues and peripheral blood lymphocytes ubiquitously expressed KIAA0247. 56 CRC patients fell into two group categories according to fecal KIAA0247 mRNA expression levels. The group with higher fecal KIAA0247 (n=22; ≥0.4897) had a significantly greater five-year overall survival rate than the group with lower fecal KIAA0247 (n = 30; <0.4897) (66.0 ± 11.6%; p=0.035, log-rank test). Fecal expression of KIAA0247 inversely related to CRC tumor size (Kendall's tau-b=-0.202; p=0.047). Immunofluorescent staining revealed that the cytoplasm of CRC cells evenly expresses KIAA0247 without 5-FU treatment, and KIAA0247 accumulates in the nucleus after 40 μM 5-FU treatment. In HCT116 p53(-/-) cells, which lack p53 cell cycle control, the proportion of cells in the G2/M phase was larger (13%) in KIAA0247-silent cells than in the respective shLuc control (10%) and KIAA0247-overexpressing cells (7%) after the addition of low dose (40 μM) 5-FU. Expression of three cyclin genes (cyclin A2, cyclin B1, and cyclin B2) also downregulated in the cells overexpressing KIAA0247., Conclusions: This is the first description of a linkage between KIAA0247 and CRC. The study's data demonstrate overexpression of KIAA0247 associates with 5-FU therapeutic benefits, and also identify the clinical significance of fecal KIAA0247 in CRC., (© 2011 Huang et al; licensee BioMed Central Ltd.)

The upregulation of fecal cytokeratin 19 (CK19) correlates with age and metastatic status in human colorectal cancer (CRC). To further explore its clinical significance in older patients (>60 years), their fecal CK19 was measured by quantitative reverse transcription-polymerase chain reaction. Differences in CK19 transcripts were compared using the nonparametric Mann-Whitney U test. Clinical significance was assessed with the chi-squared test and a binary logistic regression model. The association between overall survival and expressions of fecal CK19 in combination with other serum markers, carcinoembryonic antigen and carbohydrate antigen 19-9 (CA19-9), was evaluated using the Kaplan-Meier method. In these older groups, CRC patients had significantly higher median fecal CK19 expression (p = 0.006) than controls. The highest risk of CRC (odds ratio, 5.8; 95% confidence interval, 2.3-14.7; p < 0.001) was detected when the cutoff value for fecal CK19 expression was set at the median value of the 28 healthy controls. The lowest overall survival (29.2% ± 21.4%) occurred in patients in whom serum CA19-9 levels were high and fecal CK19 was overexpressed. Our results suggest that fecal CK19 expression is associated with CRC, and together with serum carcinoembryonic antigen or CA19-9, it can predict overall survival in older patients.

Background/aims: We attempted to specifically quantify transcripts of faecal cytokeratin 19 (CK19) and ribosomal protein L19 (RPL19) RNA expression of colorectal cancer and clarify their correlation with clinicopathological parameters and survival in combination., Methodology: Solid fecal samples were collected and preserved before any treatment. Levels of faecal CK19 and RPL19 mRNA were measured using quantitative real-time PCR. An expression level higher than median value was defined as positive., Results: Between April 2001 and June 2007, 92 patients were recruited. The levels of both markers increased in a trend as stage. Young patients (< 67 years) were correlated with higher rate of CK19+ (p = 0.001), so were higher stages but with borderline significance (p = 0.051). CK19+ and RPL19+ were highly correlated mutually (p = 0.001). Neither CK19+ (p = 0.12) nor RPL19+ (p = 0.14) alone was a prognostic factor of disease-free interval. However, CK19+/RPL19+ was shown to be with worse prognosis (p = 0.037), but not an independent factor in multivariate analysis with stage., Conclusions: Both markers were significantly higher in the patients of metastatic disease. The use of two markers will recognize the high risk group better than the single marker usage, though not reaching independent status yet. Multi-target strategy assay is suggested for fecal RNA examination.

Background: Colorectal cancer (CRC) is one of the leading causes of malignant death worldwide. Because young age of onset is often considered a poor prognostic factor for CRC, it is important to identify the poor outcomes of CRC in a younger population and to consider an aggressive approach by implementing early treatment. Our aim was to specifically quantify the fecal cytokeratin 19 (CK19) transcript from CRC patients and investigate its correlation with clinical stage, tumor malignancy, and age., Methods: The quantitation of fecal CK19 transcript was determined by a quantitative real-time reverse transcription polymerase chain in 129 CRC patients (45 younger than 60 years at diagnosis) and 85 healthy controls. The levels of CK19 protein were examined both in colonic cell lines and tissues., Results: The analysis of 45 younger CRC patients (age

Purpose: C-reactive protein, a commonly used inflammation marker, has been reported to be a prognostic factor of colorectal cancer. This prospective study was designed to confirm the prognostic value of its preoperative levels and to observe their perioperative change., Methods: Between January 2001 and September 2005, preoperative C-reactive protein levels were obtained for 212 consecutive patients (140 males) receiving elective open resection of colorectal cancer. A level higher than 0.5 mg/dl was defined as positive. They were analyzed against clinicopathologic factors. The survival of 158 curative resections was analyzed. Postoperative levels (at months 1, 3, and 6) were collected for analysis of changing trend, from the patients receiving curative surgeries., Results: Median value of preoperative C-reactive protein was 0.54 mg/dl (48.6 percent positive). Positive rate was significantly correlated with ulcerative type, larger size, higher stage, and positive carcinoembryonic antigen (>5 ng/ml). In both univariate log-rank test and multiple Cox proportional hazards regression, stage (univariate P = 0.011, and multivariate P = 0.016; hazard ratio, 6.23; 95 percent confidence interval, 1.41-27.54), C-reactive protein (0.5 mg/dl; P = 0.005, and P = 0.016; hazard ratio: 6.51; 95 percent confidence interval: 1.41-30.05), and differentiation (P = 0.006, and P = 0.043; hazard ratio, 3.53; 95 percent confidence interval, 1.04-11.98) were significant factors. Analysis of disease-free interval showed C-reactive protein was significant (P = 0.03): as level rose, prognosis worsened. The quiescent inflammation-response group (< or =0.1 mg/dl) had excellent outcomes. Postoperatively, the C-reactive protein levels declined at the third postoperative month., Conclusions: Preoperative C-reactive protein is an independent prognostic factor. The levels declined postoperatively, although with a lag. These findings seem to support the response hypothesis regarding C-reactive protein.

Colorectal cancer (CRC) is the predominant gastrointestinal malignancy and constitutes a major medical and economic burden worldwide. A thorough understanding of the oncogenes or genes related to tumorigenesis is the key to developing successful therapeutic strategies. Molecular analysis of feces constitutes a potentially potent and noninvasive method for detection of CRC. Using nested reverse transcription-polymerase chain reaction (RT-PCR) and amplified restriction fragment length polymorphism analysis, sloughed cells from the entire length of the colon and rectum were analyzed for expression of activating K-ras codon 12 mutants, which are becoming attractive targets for antisense treatment. K-ras codon 12 mutant sequences were detected in feces of 5% (1/20) of healthy controls, in feces of 41% (12/29) of CRC patients, in 10% (3/29) of isolates of tissue complementary DNA (cDNA), and in 14% (4/29) of isolates of genomic DNA. Age of patient was significantly associated with K-ras codon 12 sequences in feces: Patients with wild-type K-ras codon 12 sequences were significantly younger than those with mutated forms of K-ras codon 12. Fecal ribonucleic acid (RNA) analysis was demonstrated to be a useful for diagnosis of CRC. This technique may be suitable for screening and determining the clinical significance of active mutations of the K-ras gene in feces and would possibly be useful for identifying patients that would benefit from antisense therapy.

The altered expression of certain genes is frequently detected as a hallmark of malignant tumors. These differentially expressed genes have the potential to become molecular markers. We purified the fecal mRNA from patients with colorectal cancer to identify novel candidates by using oligo-nucleotide microarray hybridization. We identified 21 upregulated and 22 downregulated candidates with significantly altered expression in patient fecal samples that have not been previously characterized. A gene encoding a homologue of the Drosophila headcase protein (HECA) was further examined due to its high ranking and possible importance in some human cancers. A tendency towards increased expression of HECA was dependent upon the clinicopathological stage. In this report, healthy individuals expressed less HECA, either in their blood samples or feces. Moreover, we detected upregulated HECA in blood and fecal samples of patients with colorectal cancer, and its expression level was shown to be significantly correlated with disease status. Our data show that HECA may be an early-stage classifier of colorectal cancer that can discriminate between late- and early-stage disease. In conclusion, this study is the first to analyze differentially expressed genes in the feces of colorectal cancer patients using oligonucleotide microarrays. The data suggest that HECA expression levels in feces may be an effective classifier for early-stage colorectal cancer.

Early diagnosis for colorectal cancer (CRC) by monitoring of gastrointestinal epithelial cells is a possible direct approach. Although human faeces form a heterogeneous mixture of gastrointestinal mucosal epithelial cells and other materials, we have developed a method to purify total RNA from human stool samples. The gene for faecal cytokeratin 19 (CK19) was highly expressed in stools from patients with metastatic CRC, but not from patients with non-metastatic CRC or from normal individuals. Thus, purified faecal RNA can be used for the detection of differentially expressed genes. This technique may help identifying meaningful faecal RNA markers for the non-invasive screening of patients with CRC.