Genetic and epigenetic changes in colon cancer

Dominant-Negative Form of SIGIRR: SIGIRRΔE8 Promotes Tumor Growth Through Regulation of Metabolic Pathways

Colorectal carcinoma is the leading cause of cancer-related death. Previously we have shown that tumor suppressor single immunoglobulin interleukin-1-related receptor (SIGIRR) is frequently inactivated in human colorectal cancer by the increased expression of a novel SIGIRR isoform (SIGIRR^ΔE8). SIGIRR^ΔE8 showed increased retention in the cytoplasm and loss of complex glycan modification compared to the full-length SIGIRR. Now we found that the arginine residues located in the C-terminus of SIGIRR^ΔE8 serve as an endoplasmic reticulum retention signal and are required for resident protein ribophorin 1 (RPN1) interaction. In addition, we found that SIGIRR^ΔE8 exerts a direct impact on cell metabolism through interaction with the adenosine triphosphate synthase in the colorectal cancer cells. SIGIRR^ΔE8 expression promoted the metabolic shift through upregulation of mammalian target of rapamycin signaling pathway and dysregulation of mitochondrial function to promote survival and proliferation of colon cancer cells in xenograft model.

MiR-486-5p Downregulation Marks an Early Event in Colorectal Carcinogenesis

BACKGROUND

MicroRNAs are dysregulated in colorectal cancer and subsets correlated with advanced tumor stage and metastasis. Data are lacking on microRNA dysregulation from early to late-stage disease.

OBJECTIVE

The purpose of this study was to identify a microRNA signature associated with the primary tumor and metastatic site in stage IV disease and to examine whether the signature is evident in earlier stages.

DESIGN

A microRNA profile was generated and then explored in normal colon tissue (n = 5), early stage (stage I and II; n = 10), and late-stage (stage III and IV; n = 14) colorectal primary tumors via polymerase chain reaction to delineate molecular events that may promote colorectal carcinogenesis.

SETTING

Genome-wide microRNA expression profiling was performed.

PATIENTS

A total of 14 patient-matched stage IV primary colorectal cancer tumors and corresponding liver metastases were included.

MAIN OUTCOME MEASURES

MicroRNA array technology was used to identify microRNA expression-predictive metastatic potential in the primary tumor.

RESULTS

A distinct 9-member signature group of microRNAs was concurrent in stage IV primary colorectal cancer and their corresponding liver metastases, when compared with surrounding unaffected colon and liver tissue (microRNA-18b, microRNA-93, microRNA-182, microRNA-183, microRNA21, microRNA-486-5p, microRNA-500a, microRNA-552, and microRNA-941). Of the microRNA panel, only microRNA486-5p was differentially expressed in early stage colorectal cancer samples compared with normal tissue (p = 0.001) and additionally differentially expressed between late-stage colorectal cancer samples and normal tissue (p < 0.01).

LIMITATIONS

Our microRNA profile was generated in a small subset of patients and will require validation in more samples.

CONCLUSIONS

We identified a distinct microRNA signature in primary colon and matched metastatic disease. On additional investigation, 1 microRNA was differentially expressed in both early and late-stage cancer patient samples, and it may herald an early event in colorectal carcinogenesis. This study warrants additional investigation with a larger patient cohort to better understand the effect of microRNAs in carcinogenesis. See Video Abstract at http://links.lww.com/DCR/A723.

Aberrant DNA Methylation: Implications in Racial Health Disparity

Background

Incidence and mortality rates of colorectal carcinoma (CRC) are higher in African Americans (AAs) than in Caucasian Americans (CAs). Deficient micronutrient intake due to dietary restrictions in racial/ethnic populations can alter genetic and molecular profiles leading to dysregulated methylation patterns and the inheritance of somatic to germline mutations.

Materials and Methods

Total DNA and RNA samples of paired tumor and adjacent normal colon tissues were prepared from AA and CA CRC specimens. Reduced Representation Bisulfite Sequencing (RRBS) and RNA sequencing were employed to evaluate total genome methylation of 5’-regulatory regions and dysregulation of gene expression, respectively. Robust analysis was conducted using a trimming-and-retrieving scheme for RRBS library mapping in conjunction with the BStool toolkit.

Results

DNA from the tumor of AA CRC patients, compared to adjacent normal tissues, contained 1,588 hypermethylated and 100 hypomethylated differentially methylated regions (DMRs). Whereas, 109 hypermethylated and 4 hypomethylated DMRs were observed in DNA from the tumor of CA CRC patients; representing a 14.6-fold and 25-fold change, respectively. Specifically; CHL1, 4 anti-inflammatory genes (i.e., NELL1, GDF1, ARHGEF4, and ITGA4), and 7 miRNAs (of which miR-9-3p and miR-124-3p have been implicated in CRC) were hypermethylated in DNA samples from AA patients with CRC. From the same sample set, RNAseq analysis revealed 108 downregulated genes (including 14 ribosomal proteins) and 34 upregulated genes (including POLR2B and CYP1B1 [targets of miR-124-3p]) in AA patients with CRC versus CA patients.

Conclusion

DNA methylation profile and/or products of its downstream targets could serve as biomarker(s) addressing racial health disparity.

High expression of piwi-like RNA-mediated gene silencing 1 is associated with poor prognosis via regulating transforming growth factor-β receptors and cyclin-dependent kinases in breast cancer

Previous studies have demonstrated that abnormal expression levels of PIWI may serve a crucial role in tumorigenesis. However, the pathological role and its association with prognosis remains to be fully elucidated. In the present study, the expression levels of piwi‑like RNA‑mediated gene silencing 1 (HIWI) and piwi‑like RNA‑mediated gene silencing 2 (HILI) in breast cancer tissues were reported to be high. The high expression levels of HIWI are correlated with poor prognosis in detected patients. In addition, by overexpression and interference, it was demonstrated that HIWI promotes the activity of breast cancer cells while depression of HIWI may induce apoptosis of breast cancer cells. It was additionally identified that suppression of HIWI may arrest the cells at the G2/M stage. The expression levels of transforming growth factor‑β receptor (TβR)I, TβRII, cyclin‑dependent kinase (CDK)4, CDK6 and CDK8 were observed to be regulated by HIWI, which indicated a novel mechanism of HIWI in the regulation of breast cancer progression. The present study provides novel insight into the HIWI expression in breast cancer, providing a potential biomarker for assessment of prognosis and therapy of breast cancer.

EMAST is associated with a poor prognosis in microsatellite instable metastatic colorectal cancer

Purpose

To determine the frequency and prognostic value of elevated microsatellite alterations at selected tetranucleotide repeats (EMAST) in metastatic colorectal cancer (mCRC) patients in relation to microsatellite instability (MSI) status and MSH3 protein expression.

Material and Methods

The frequency of EMAST was evaluated in mCRC patients with MSI tumors and microsatellite stable (MSS) tumors. A literature overview was performed to compare the frequency of EMAST in our study with existing data. Immunohistochemistry for MSH3 was compared with EMAST status. Outcome was studied in terms of overall survival (OS) of mCRC patients with MSI and MSS tumors.

Results

EMAST was evaluated in 89 patients with MSI tumors (including 39 patients with Lynch syndrome) and 94 patients with MSS tumors. EMAST was observed in 45.9% (84 out of 183) of patients, with an increased frequency in MSI tumors (79.8% versus 13.8%, p < 0.001). We found no correlation between EMAST and MSH3 protein expression. There was no effect of EMAST on prognosis in patients with MSS tumors, but patients with MSI / non-EMAST tumors had a significantly better prognosis than patients with MSI / EMAST tumors (OS: HR 3.22, 95% CI 1.25-8.30).

Conclusion

Frequency of EMAST was increased in mCRC patients with MSI tumors, compared to MSS tumors. Our data suggest that the presence of EMAST correlates with worse OS in these patients. There was no effect of EMAST on the prognosis of patients with MSS tumors. A limitation of our study is the small number of patients in our subgroup analysis.

Molecular mechanisms for inhibition of colon cancer cells by combined epigenetic-modulating epigallocatechin gallate and sodium butyrate

Bioactive compounds are considered safe and have been shown to alter genetic and epigenetic profiles of tumor cells. However, many of these changes have been reported at molecular concentrations higher than physiologically achievable levels. We investigated the role of the combinatorial effects of epigallocatechin gallate (EGCG), a predominant polyphenol in green tea, and sodium butyrate (NaB), a dietary microbial fermentation product of fiber, in the regulation of survivin, which is an overexpressed anti-apoptotic protein in colon cancer cells. For the first time, our study showed that the combination treatment induced apoptosis and cell cycle arrest in RKO, HCT-116 and HT-29 colorectal cancer cells. This was found to be regulated by the decrease in HDAC1, DNMT1, survivin and HDAC activity in all three cell lines. A G2/M arrest was observed for RKO and HCT-116 cells, and G1 arrest for HT-29 colorectal cancer cells for combinatorial treatment. Further experimentation of the molecular mechanisms in RKO colorectal cancer (CRC) cells revealed a p53-dependent induction of p21 and an increase in nuclear factor kappa B (NF-κB)-p65. An increase in double strand breaks as determined by gamma-H2A histone family member X (γ-H2AX) protein levels and induction of histone H3 hyperacetylation was also observed with the combination treatment. Further, we observed a decrease in global CpG methylation. Taken together, these findings suggest that at low and physiologically achievable concentrations, combinatorial EGCG and NaB are effective in promoting apoptosis, inducing cell cycle arrest and DNA-damage in CRC cells.

Clinicopathological relevance of BRAF mutations in human cancer

BRAF represents one of the most frequently mutated protein kinase genes in human tumours. The mutation is commonly tested in pathology practice. BRAF mutation is seen in melanoma, papillary thyroid carcinoma (including papillary thyroid carcinoma arising from ovarian teratoma), ovarian serous tumours, colorectal carcinoma, gliomas, hepatobiliary carcinomas and hairy cell leukaemia. In these cancers, various genetic aberrations of the BRAF proto-oncogene, such as different point mutations and chromosomal rearrangements, have been reported. The most common mutation, BRAF V600E, can be detected by DNA sequencing and immunohistochemistry on formalin fixed, paraffin embedded tumour tissue. Detection of BRAF V600E mutation has the potential for clinical use as a diagnostic and prognostic marker. In addition, a great deal of research effort has been spent in strategies inhibiting its activity. Indeed, recent clinical trials involving BRAF selective inhibitors exhibited promising response rates in metastatic melanoma patients. Clinical trials are underway for other cancers. However, cutaneous side effects of treatment have been reported and therapeutic response to cancer is short-lived due to the emergence of several resistance mechanisms. In this review, we give an update on the clinical pathological relevance of BRAF mutation in cancer. It is hoped that the review will enhance the direction of future research and assist in more effective use of the knowledge of BRAF mutation in clinical practice.

Microsatellite instability and loss of heterozygosity detected in middle-aged patients with sporadic colon cancer: A retrospective study

Microsatellite instability (MSI) is a mutator phenotype that results from a defective mismatch repair (MMR) pathway. The present study examined the incidence of MSI and loss of heterozygosity (LOH) according to five markers from the panel of the National Cancer Institute (NCI) in 38 colorectal cancer (CRC) patients from the United Arab Emirates (UAE). MSI and LOH were analyzed using fragment analyses in a multiplex PCR setting on a capillary array electrophoresis platform. The expression of the MMR proteins, hMLH1 and hMSH2, was analyzed using immunohistochemistry. The cohort consisted of 17 females (44.7%) and 21 males (55.3%) with mean ages of 59.9 and 63.3 years, respectively. The overall MSI incidence was 31.3% (95% CI, 16.1–50.0), and included three patients with high MSI (MSI-H; 9.4%; 95% CI, 2.0–25.0) and seven patients with low MSI (MSI-L; 21.9%; 95% CI, 10.7–39). LOH was detected in three patients, while the remaining 25 patients (65.8%) showed no instability and were therefore classified as microsatellite stable (MSS). MSI was detected in the following screened markers: Bat25 in seven patients, Bat26 in three patients, adenomatous polyposis coli (APC; D5S346) in five patients, AFM093xh3 (D2S123) in two patients and Mfd15 (D17S250) in three patients. Of the five MSI-positive patients, four (80%) were evidently younger, aged 38, 48, 49 and 59 years, respectively. The MSI-H incidence (9.4%) was lower compared with that of other ethnic groups. In terms of the MMR proteins, hMLH1 expression was deficient in seven patients, of whom three were MSI-H patients, and hMSH2 was deficient in three patients. Fisher’s exact test showed significant associations between hMLH1 and MSI when classified as MSS, MSI-L or MSI-H (P=0.0003). No such association was observed with abnormal MMR protein expression, age, cancer stage or gender.

The Diagnostic and Prognostic Role of microRNA in Colorectal Cancer - a Comprehensive review

The discovery of microRNA, a group of regulatory short RNA fragments, has added a new dimension to the diagnosis and management of neoplastic diseases. Differential expression of microRNA in a unique pattern in a wide range of tumor types enables researches to develop a microRNA-based assay for source identification of metastatic disease of unknown origin. This is just one example of many microRNA-based cancer diagnostic and prognostic assays in various phases of clinical research.

Since colorectal cancer (CRC) is a phenotypic expression of multiple molecular pathways including chromosomal instability (CIN), micro-satellite instability (MIS) and CpG islands promoter hypermethylation (CIMP), there is no one-unique pattern of microRNA expression expected in this disease and indeed, there are multiple reports published, describing different patterns of microRNA expression in CRC.

The scope of this manuscript is to provide a comprehensive review of the scientific literature describing the dysregulation of and the potential role for microRNA in the management of CRC. A Pubmed search was conducted using the following MeSH terms, "microRNA" and "colorectal cancer". Of the 493 publications screened, there were 57 papers describing dysregulation of microRNA in CRC.

Complex patterns of altered MicroRNA expression during the adenoma-adenocarcinoma sequence for microsatellite-stable colorectal cancer

PURPOSE

MicroRNAs are short noncoding RNAs that regulate gene expression and are over- or underexpressed in most tumors, including colorectal adenocarcinoma. MicroRNAs are potential biomarkers and therapeutic targets and agents, but limited information on microRNAome alterations during progression in the well-known adenoma-adenocarcinoma sequence is available to guide their usage.

EXPERIMENTAL DESIGN

We profiled 866 human microRNAs by microarray analysis in 69 matched specimens of microsatellite-stable adenocarcinomas, adjoining precursor adenomas including areas of high- and low-grade dysplasia, and nonneoplastic mucosa.

RESULTS

We found 230 microRNAs that were significantly differentially expressed during progression, including 19 not reported previously. Altered microRNAs clustered into two major patterns of early (type I) and late (type II) differential expression. The largest number (n = 108) was altered at the earliest step from mucosa to low-grade dysplasia (subtype IA) prior to major nuclear localization of β-catenin, including 36 microRNAs that had persistent differential expression throughout the entire sequence to adenocarcinoma. Twenty microRNAs were intermittently altered (subtype IB), and six were transiently altered (subtype IC). In contrast, 33 microRNAs were altered late in high-grade dysplasia and adenocarcinoma (subtype IIA), and 63 in adenocarcinoma only (subtype IIB). Predicted targets in 12 molecular pathways were identified for highly altered microRNAs, including the Wnt signaling pathway leading to low-grade dysplasia. β-catenin expression correlated with downregulated microRNAs.

CONCLUSIONS

Our findings suggest that numerous microRNAs play roles in the sequence of molecular events, especially early events, resulting in colorectal adenocarcinoma. The temporal patterns and complexity of microRNAome alterations during progression will influence the efficacy of microRNAs for clinical purposes.

Four molecular subtypes of colorectal cancer and their precursor lesions

CONTEXT

In addition to chromosomal instability and microsatellite instability (MSI), a third pathway, epigenetic instability, has been implicated in progression to colorectal carcinogenesis. CpG island methylator phenotype (CIMP) refers to a subset of colorectal cancers (CRCs) that occur through the epigenetic instability pathway and that are characterized by widespread hypermethylation of promoter CpG island loci, resulting in the inactivation of several tumor suppressor genes or tumor-related genes. Colorectal cancers can be classified into 4 molecular subtypes according to their CIMP and MSI statuses: CIMP+/MSI+, CIMP+/MSI-, CIMP-/MSI+, and CIMP-/MSI-. There are differences between Western (United States and European Union) and Eastern (Korea and China) populations in the number of CRCs that are MSI+, and in the number of MSI+ CRCs that are CIMP+.

OBJECTIVE

To review the clinicopathologic and molecular features of the 4 molecular subtypes of CRCs and their precursor lesions, and to emphasize geographic differences in CRCs between Eastern and Western populations.

DATA SOURCES

This article is based on the author's own experimental data and a literature review of relevant articles indexed in PubMed (US National Library of Medicine).

CONCLUSION

The 4 molecular subtypes of CRC that are defined by their CIMP and MSI statuses are characterized by their own distinct clinicopathologic and molecular features and precursor lesions. In particular, the clinicopathologic features of MSI+ CRCs differ depending on the CIMP status. Further understanding of the heterogeneity in CRC molecular pathways may help to explain the diverse morphologic features of CRCs.

Transcriptome instability in colorectal cancer identified by exon microarray analyses: Associations with splicing factor expression levels and patient survival

Background

Colorectal cancer (CRC) is a heterogeneous disease that, on the molecular level, can be characterized by inherent genomic instabilities; chromosome instability and microsatellite instability. In the present study we analyze genome-wide disruption of pre-mRNA splicing, and propose transcriptome instability as a characteristic that is analogous to genomic instability on the transcriptome level.

Methods

Exon microarray profiles from two independent series including a total of 160 CRCs were investigated for their relative amounts of exon usage differences. Each exon in each sample was assigned an alternative splicing score calculated by the FIRMA algorithm. Amounts of deviating exon usage per sample were derived from exons with extreme splicing scores.

Results

There was great heterogeneity within both series in terms of sample-wise amounts of deviating exon usage. This was strongly associated with the expression levels of approximately half of 280 splicing factors (54% and 48% of splicing factors were significantly correlated to deviating exon usage amounts in the two series). Samples with high or low amounts of deviating exon usage, associated with overall transcriptome instability, were almost completely separated into their respective groups by hierarchical clustering analysis of splicing factor expression levels in both sample series. Samples showing a preferential tendency towards deviating exon skipping or inclusion were associated with skewed transcriptome instability. There were significant associations between transcriptome instability and reduced patient survival in both sample series. In the test series, patients with skewed transcriptome instability showed the strongest prognostic association (P = 0.001), while a combination of the two characteristics showed the strongest association with poor survival in the validation series (P = 0.03).

Conclusions

We have described transcriptome instability as a characteristic of CRC. This transcriptome instability has associations with splicing factor expression levels and poor patient survival.

Germline polymorphisms in the one-carbon metabolism pathway and DNA methylation in colorectal cancer

Dietary intake of one-carbon nutrients (methyl donors) and germline variants in the one-carbon metabolism genes may influence global DNA methylation level and methylation in promoter CpG islands. In this study, we evaluated the relationship between single nucleotide polymorphisms (SNPs) in the one-carbon metabolism pathway and DNA methylation status in colorectal cancer. Utilizing 182 colorectal cancers cases in two prospective cohort studies, we determined the CpG island methylator phenotype (CIMP) status on eight CIMP-specific promoters and measured LINE-1 methylation level that correlates well with genome-wide DNA methylation level. We genotyped 23 nonsynonymous SNPs in the one-carbon metabolism genes using buffy coat DNA. Most of the 23 SNPs in the one-carbon metabolism pathway were not significantly associated with CIMP-high status (> or = 6/8 methylated promoters). However, the MTHFR 429 Ala/Ala variant (rs1801131) and the TCN2 259 Arg/Arg variant (rs1801198) were associated with CIMP-high status (MTHFR 429 multivariate odds ratio (MV OR) = 7.56; 95% confidence interval (CI), 1.32-43.3; p trend = 0.10; TCN2 259 Arg/Arg variant MV OR = 3.82; 95% CI, 1.02-14.4; p trend = 0.06). The one-carbon metabolism genotypes were not significantly associated with LINE-1 methylation, although there were modest differences in mean LINE-1 methylation levels between certain genotypes. Collectively, these exploratory data provide suggestive evidence for the association of MTHFR 429 Ala/ Ala and TCN2 259 Arg/Arg and CIMP status in colorectal cancer.

Argonaute proteins: potential biomarkers for human colon cancer

BACKGROUND

Although Argonaute proteins are considered to play important roles in stem cell self-renewal, RNA interference (RNAi) and translational regulation, relatively little is known about their functions in human disease. In this study, we investigated the expression of eight members of human Argonaute family in colon cancer and identified their potential roles in tumor development and progression.

METHODS

Antibodies against human Argonaute proteins were prepared by immunizing rabbits with synthetic peptides derived from the sequences of Argonaute members. Then we constructed a tissue microarray containing 75 specimens from colon cancer and 75 specimens from adjacent non-cancer tissue, and assayed eight different proteins (EIF2C1, EIF2C2, EIF2C3, EIF2C4, PIWIL1, PIWIL2, PIWIL3 and PIWIL4) by immunohistochemistry on consecutive formalin-fixed tissue microarray sections.

RESULTS

The expression of EIF2C1-4 and PIWIL1-4 was significantly higher in tumorous tissue than in adjacent tissue. Notably, a significant correlation was observed between the positive expression of EIF2C2, EIF2C3, EIF2C4, PIWIL4 and the presence of distant metastasis. Logistic regression analysis revealed that an increased expression of EIF2C1 and PIWIL2 was significantly associated with occurrence of colon cancer tissue compared with non-cancer tissue.

CONCLUSIONS

Argonaute proteins are overexpressed in colon cancer relative to adjacent non-cancer tissue. The expression of EIF2C2-4 and PIWIL4 appears increased in advanced tumors with distant metastasis, suggesting it may promote tumor invasion. Furthermore, EIF2C1 and PIWIL2 might represent novel colon cancer markers with early diagnostic significance.

KRAS mutation testing in colorectal cancer

In the US, colorectal cancer is the third leading cause of cancer-related death. Approximately 20% of patients present with metastatic disease, and an additional 30% to 40% develop metastasis during the course of their disease. Patients with metastatic colon cancer have a 5-year survival rate of only 11%. Although surgery is the mainstay of treatment for early stage colon cancer, adjuvant treatment is usually used in patients advanced stage disease. In particular, epidermal growth factor receptor (EGFR) inhibitor therapies have emerged as effective treatments in a subset of patients with metastatic colorectal carcinoma. Two anti-EGFR biologics, cetuximab and panitumumab, have been approved by the Food and Drug Administrations for the treatment of refractory metastatic colorectal carcinoma. Mounting evidence has shown that these therapies are ineffective in tumors with mutations of codons 12 and 13 of exon 2 of the KRAS gene. Because of this compelling data, the National Comprehensive Cancer Network and the American Society of Clinical Oncology have recommended determination of KRAS mutation status in all patients with metastatic colorectal cancer who are candidates for anti-EGFR therapy. Anatomic pathologists play an integral role in coordinating the testing for KRAS mutations, as this assay is performed on tissue samples selected by the pathologist. Herein, the authors present an up-to-date review of the biologic, clinical, and laboratory aspects of KRAS mutation testing in colorectal cancer.

Identification of microRNAs caused by DNA methylation that induce metastasis

Metastasis is a common feature in advanced cancers. To elucidate the mechanism underlying metastasis from analysis of primary disease would have substantial clinical benefit. MicroRNAs (miRNAs) have started a revolution in molecular biology, and emerged as key players in carcinogenesis. They have been identified in various tumor types, showing that different sets of miRNAs are usually deregulated in different cancers. Moreover, some miRNAs are aberrantly methylated and silenced, causing tumorigenesis. In the paper evaluated, the authors identified aberrantly methylated and silenced miRNAs that are cancer-specific using miRNA microarray techniques. Functional analyses for the selected genes proved that these miRNAs act on C-MYC, E2F3, CDK6 and TGIF2, resulting in metastasis through aberrant methylation of the miRNAs. These findings may have broad implications for mechanisms underlying metastasis in malignancies, and may be applicable to advance research in the clinical setting.

Up-regulation and clinical relevance of novel helicase homologue DHX32 in colorectal cancer

Background

This study aimed to find novel biomarkers for colorectal cancer.

Methods

Fluorescent mRNA differential display PCR (DD-PCR) was used to screen the genes differentially expressed in colorectal cancer tissues and their adjacent tissues. The differentially expressed genes were confirmed by real-time PCR and then their clinical relevance (such as association with tumor location and lymph gland metastasis) was further investigated.

Results

We identified by DD-PCR a novel RNA helicase, DHX32, which showed higher expression in colorectal cancer tissues than their adjacent tissues, and this result was confirmed by real time RT-PCR. In addition, we found that the level of DHX32 gene expression in colorectal cancer was significantly associated with cancer location, lymph gland metastasis, cancer nodal status, differentiation grade, and Dukes, stage.

Conclusion

DHX32 may play an important role in the development of colorectal cancer and could serve as a novel biomarker for colorectal cancer after additional investigation.