Heterogeneous immunogenomic features and distinct escape mechanisms in multifocal hepatocellular carcinoma.

BACKGROUND & AIMS: The presence of multifocal tumors, developed either from intrahepatic metastasis (IM) or multicentric occurrence (MO), is a distinct feature of hepatocellular carcinoma (HCC). Immunogenomic characterization of multifocal HCC is important for understanding immune escape in different lesions and developing immunotherapy. METHODS: We combined whole-exome/transcriptome sequencing, multiplex immunostaining, immunopeptidomes, T cell receptor (TCR) sequencing and bioinformatic analyses of 47 tumors from 15 patients with HCC and multifocal lesions. RESULTS: IM and MO demonstrated distinct clonal architecture, mutational spectrum and genetic susceptibility. The immune microenvironment also displayed spatiotemporal heterogeneity, such as less T cell and more M2 macrophage infiltration in IM and higher expression of inhibitory immune checkpoints in MO. Similar to mutational profiles, shared neoantigens and TCR repertoires among tumors from the same patients were abundant in IM but scarce in MO. Combining neoantigen prediction and immunopeptidomes identified T cell-specific neoepitopes and achieved a high verification rate in vitro. Immunoediting mainly occurred in MO but not IM, due to the relatively low immune infiltration. Loss of heterozygosity of human leukocyte antigen (HLA) alleles, identified in 17% of multifocal HCC, hampered the ability of major histocompatibility complex to present neoantigens, especially in IM. An integrated analysis of Immunoscore, immunoediting, TCR clonality and HLA loss of heterozygosity in each tumor could stratify patients into 2 groups based on whether they have a high or low risk of recurrence (p = 0.038). CONCLUSION: Our study comprehensively characterized the genetic structure, neoepitope landscape, T cell profile and immunoediting status that collectively shape tumor evolution and could be used to optimize personalized immunotherapies for multifocal HCC. LAY SUMMARY: Immunogenomic features of multifocal hepatocellular carcinoma (HCC) are important for understanding immune-escape mechanisms and developing more effective immunotherapy. Herein, comprehensive immunogenomic characterization showed that diverse genomic structures within multifocal HCC would leave footprints on the immune landscape. Only a few tumors were under the control of immunosurveillance, while others evaded the immune system through multiple mechanisms that led to poor prognosis. Our study revealed heterogeneous immunogenomic landscapes and immune-constrained tumor evolution, the understanding of which could be used to optimize personalized immunotherapies for multifocal HCC.

Effect of exosomal miRNA on cancer biology and clinical applications.

Exosomes, extracellular vesicles with diameters ranging from 30 to 150 nm, are widely present in various body fluids. Recently, microRNAs (miRNAs) have been identified in exosomes, the biogenesis, release, and uptake of which may involve the endosomal sorting complex required for transport (ESCRT complex) and relevant proteins. After release, exosomes are taken up by neighboring or distant cells, and the miRNAs contained within modulate such processes as interfering with tumor immunity and the microenvironment, possibly facilitating tumor growth, invasion, metastasis, angiogenesis and drug resistance. Therefore, exosomal miRNAs have a significant function in regulating cancer progression. Here, we briefly review recent findings regarding tumor-derived exosomes, including RNA sorting and delivering mechanism. We then describe the intercommunication occurring between different cells via exosomal miRNAs in tumor microenvironmnt, with impacts on tumor proliferation, vascularization, metastasis and other biological characteristics. Finally, we highlight the potential role of these molecules as biomarkers in cancer diagnosis and prognosis and tumor resistance to therapeutics.

Emerging role of exosome-derived long non-coding RNAs in tumor microenvironment.

Exosomes are extracellular vesicles released by many cell types and have been attributed for their roles in many diseases including cancer. Exosomes secreted by tumor cells and stromal cells are critical mediators of intercellular communication in tumor microenvironments. Long noncoding RNAs (lncRNAs) are selectively sorted into exosomes and can regulate cancer onset and progression in a variety of ways. In this review, we summarize the characteristics of exosomal lncRNAs and their dysregulation in multiple types of cancer. We provide an overview of current research on exosomal lncRNAs in tumor microenvironments, especially the functions of exosomal lncRNAs in regulating tumor biology. A deeper understanding of the role of exosomal lncRNAs in the tumor microenvironment may help provide new diagnostic and prognostic markers for cancer.

The Biological Effect and Clinical Application of Long Noncoding RNAs in Colorectal Cancer.

Colorectal cancer (CRC) is one of the most common malignancies in the world. Easier recurrence and metastasis is the main cause of mortality in CRC patients, and the markers applied for diagnosis and treatment of CRC is still urgently needed to early diagnose and evaluate therapeutic effect. Long noncoding RNA (lncRNA) is a class of noncoding RNA that the length is more than 200 nucleotides. With the development of sequencing technique about transcriptome, increasing lncRNAs are focused on their function and mechanism related to the nosogenesis and pathology of CRC. Recent studies report that lncRNAs acted as crucial role in CRC and could be as biomarker for CRC diagnosis and treatment. In this review, we display the regulation of lncRNA by interacting with DNA, RNA and protein and highlight the double role of lncRNAs as oncogene or anti-tumor gene involved in Wnt signaling pathway, p53 signaling pathway or others to be an regulator in CRC development. Lastly, we discuss some new finding of lncRNAs, especially lncRNA in exosome, which could be as potential markers for diagnosis and treatment of CRC in future.

Advances in Engineered Macrophages: A New Frontier in Cancer Immunotherapy.

Macrophages, as pivotal cells within the tumour microenvironment, significantly influence the impact of and reactions to treatments for solid tumours. The rapid evolution of bioengineering technology has revealed the vast potential of engineered macrophages in immunotherapy, disease diagnosis, and tissue engineering. Given this landscape, the goal of harnessing and innovating macrophages as a novel strategy for solid tumour immunotherapy cannot be overstated. The diverse strategies for engineered macrophages in the realm of cancer immunotherapy, encompassing macrophage drug delivery systems, chimeric antigen receptor macrophage therapy, and synergistic treatment approaches involving bacterial outer membrane vesicles and macrophages, are meticulously examined in this review. These methodologies are designed to enhance the therapeutic efficacy of macrophages against solid tumours, particularly those that are drug-resistant and metastatic. Collectively, these immunotherapies are poised to supplement and refine current solid tumour treatment paradigms, thus heralding a new frontier in the fight against malignant tumours.

Targeting neutrophils: Mechanism and advances in cancer therapy.

BACKGROUND: Cancer is a thorny problem which cannot be conquered by mankind at present and recent researchers have put their focus on tumor microenviroment. Neutrophils, the prominent leukocytes in peripheral blood that accumulate in tumours, serves as frontline cells in response to tumour progression owing to the rapid development of micro biotechnology. Hence, targeted therapy with these neutrophils has made targeting treatment a promising field in cancer therapy. MAIN BODY: We broadly summarise some studies on the phenotypes and functions of tumour-associated neutrophils as well as the unique web-like products of neutrophils that play a role in cancer progression-neutrophil extracellular traps-and the interactions between neutrophils and the tumour microenvironment. Moreover, several targeted neutrophils therapeutic studies have made some progress and provided potential strategies for the treatment of cancer. CONCLUSION: This review aims to offer a holistic perspective on therapeutic interventions targeting neutrophils to further inspire more researches on cancer therapies.

An assessment system for clinical and biological interpretability in ulcerative colitis.

Ulcerative colitis (UC) is a serious inflammatory bowel disease (IBD) with high morbidity and mortality worldwide. As the traditional diagnostic techniques have various limitations in the practice and diagnosis of early ulcerative colitis, it is necessary to develop new diagnostic models from molecular biology to supplement the existing methods. In this study, we developed a machine learning-based synthesis to construct an artificial intelligence diagnostic model for ulcerative colitis, and the correctness of the model is verified using an external independent dataset. According to the significantly expressed genes related to the occurrence of UC in the model, an unsupervised quantitative ulcerative colitis related score (UCRScore) based on principal coordinate analysis was established. The UCRScore is not only highly generalizable across UC bulk cohorts at different stages, but also highly generalizable across single-cell datasets, with the same effect in terms of cell numbers, activation pathways and mechanisms. As an important role of screening genes in disease occurrence, based on connectivity map analysis, 5 potential targeting molecular compounds were identified, which can be used as an additional supplement to the therapeutic of UC. Overall, this study provides a potential tool for differential diagnosis and assessment of bio-pathological changes in UC at the macroscopic level, providing an opportunity to optimize the diagnosis and treatment of UC.

RNA methylation-mediated LINC01559 suppresses colorectal cancer progression by regulating the miR-106b-5p/PTEN axis.

Long noncoding RNAs (lncRNAs) regulate multiple biological effects in cancers. Recently, RNA methylation has been found to modify not only coding RNAs but also some noncoding RNAs. How RNA methylation affects lncRNAs to affect colorectal cancer (CRC) progression remains elusive. The expression of LINC01559 was explored through RNA sequencing, quantitative real-time PCR (qRT-PCR) and in situ hybridization (ISH). The preliminary exploration of its function was performed using Western blotting (WB) and immunohistochemistry (IHC). Functional experiments in vitro and in vivo were conducted to explore the biological functions of LINC01559 in CRC. The LINC01559/miR-106-5p/PTEN axis was verified through fluorescence in situ hybridization (FISH), luciferase assays, and rescue experiments. RIP-sequencing, m6A RNA immunoprecipitation (MeRIP) assays and bioinformatic analysis were conducted to determine the upstream mechanism of LINC01559. The results showed that LINC01559 was downregulated in CRC compared with normal controls. Lower expression of LINC01559 in CRC patients predicted a poor prognosis. In addition, PTEN was found to be positively correlated with LINC01559, and miR-106b-5p could be the link between LINC01559 and PTEN. Then, silencing LINC01559 restored the malignant phenotype of CRC cells, while cotransfection of miR-106b-5p inhibitor neutralized this effect. Mechanistically, we found abundant m6A modification sites on LINC01559. Then, we uncovered these sites as potential targets of METTL3 through experiments in vivo. The results revealed a negative functional regulation of the LINC01559/miR-106b-5p/PTEN axis in CRC progression and explored a new mechanism of METTL3-mediated m6A modification on LINC01559. These results elucidate a novel potential therapeutic target for CRC treatment.

The influence of 18F-fluorodeoxyglucose positron emission tomography/computed tomography on the N- and M-staging and subsequent clinical management of intrahepatic cholangiocarcinoma.

Background: Intrahepatic cholangiocarcinoma (ICC) is a highly metastatic cancer. 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) enables sensitive tumor and metastasis detection. Our aim is to evaluate the influence of pre-treatment PET/CT on the N- and M-staging and subsequent clinical management in ICC patients. Methods: Between August 2010 and August 2018, 660 consecutive ICC patients, without prior anti-tumor treatments nor other malignancies, were enrolled. The diagnostic performance of PET/CT on the N- and M-staging was compared with conventional imaging, and the preoperative staging accuracy and treatment re-allocation by PET/CT were retrospectively calculated. Survival difference was compared between patients receiving PET/CT or not after propensity score matching. Results: Patients were divided into group A (n=291) and group B (n=369) according to whether PET/CT was performed. Among 291 patients with both PET/CT and conventional imaging for staging in group A, PET/CT showed significantly higher sensitivity (83.0% vs. 70.5%, P=0.001), specificity (88.3% vs. 74.9%, P<0.001) and accuracy (86.3% vs. 73.2%, P<0.001) than conventional imaging in diagnosing regional lymph node metastasis, as well as higher sensitivity (87.8% vs. 67.6%, P<0.001) and accuracy (93.5% vs. 89.3%, P=0.023) in diagnosing distant metastasis. Overall, PET/CT improved the accuracy of preoperative staging from 60.1% to 71.8% (P<0.001), and modified clinical treatment strategy in 5.8% (17/291) of ICC patients, with unique roles in different tumor-node-metastasis (TNM) stages. High tumor-to-non-tumor ratio (TNR) predicted poor overall survival [hazard ratio (HR) = 2.17; 95% confidence interval (CI): 1.49-3.15; P<0.001]. Furthermore, patients performing PET/CT had longer overall survival compared with those without PET/CT (HR =0.74; 95% CI: 0.58-0.93; P=0.011) after propensity score matching. Conclusions: PET/CT was valuable for diagnosing regional lymph node metastasis and distant metastasis in ICC patients, and facilitated accurate tumor staging and optimal treatment allocation.

Spatiotemporal Immune Landscape of Colorectal Cancer Liver Metastasis at Single-Cell Level.

Liver metastasis, the leading cause of colorectal cancer mortality, exhibits a highly heterogeneous and suppressive immune microenvironment. Here, we sequenced 97 matched samples by using single-cell RNA sequencing and spatial transcriptomics. Strikingly, the metastatic microenvironment underwent remarkable spatial reprogramming of immunosuppressive cells such as MRC1 + CCL18 + M2-like macrophages. We further developed scMetabolism, a computational pipeline for quantifying single-cell metabolism, and observed that those macrophages harbored enhanced metabolic activity. Interestingly, neoadjuvant chemotherapy could block this status and restore the antitumor immune balance in responsive patients, whereas the nonresponsive patients deteriorated into a more suppressive one. Our work described the immune evolution of metastasis and uncovered the black box of how tumors respond to neoadjuvant chemotherapy. SIGNIFICANCE: We present a single-cell and spatial atlas of colorectal liver metastasis and found the highly metabolically activated MRC1 + CCL18 + M2-like macrophages in metastatic sites. Efficient neoadjuvant chemotherapy can slow down such metabolic activation, raising the possibility to target metabolism pathways in metastasis.This article is highlighted in the In This Issue feature, p. 1.

Single-cell transcriptomic analysis suggests two molecularly subtypes of intrahepatic cholangiocarcinoma.

Intrahepatic cholangiocarcinoma (iCCA) is a highly heterogeneous cancer with limited understanding of its classification and tumor microenvironment. Here, by performing single-cell RNA sequencing on 144,878 cells from 14 pairs of iCCA tumors and non-tumor liver tissues, we find that S100P and SPP1 are two markers for iCCA perihilar large duct type (iCCAphl) and peripheral small duct type (iCCApps). S100P + SPP1- iCCAphl has significantly reduced levels of infiltrating CD4+ T cells, CD56+ NK cells, and increased CCL18+ macrophages and PD1+CD8+ T cells compared to S100P-SPP1 + iCCApps. The transcription factor CREB3L1 is identified to regulate the S100P expression and promote tumor cell invasion. S100P-SPP1 + iCCApps has significantly more SPP1+ macrophage infiltration, less aggressiveness and better survival than S100P + SPP1- iCCAphl. Moreover, S100P-SPP1 + iCCApps harbors tumor cells at different status of differentiation, such as ALB + hepatocyte differentiation and ID3+ stemness. Our study extends the understanding of the diversity of tumor cells in iCCA.

N6-methyladenosine-induced circ1662 promotes metastasis of colorectal cancer by accelerating YAP1 nuclear localization.

Tumor metastasis is the leading cause of death in patients with colorectal cancer (CRC). Circular RNAs (circRNAs) have been shown to be involved in cancer progression. However, the regulatory mechanisms of circRNAs involved in CRC tumor metastasis are currently unknown. Methods: High-throughput sequencing was performed on 6 pairs of CRC and adjacent normal tissues to identify the expression profiles of mRNA and circRNA. circ1662 was assessed by RNA-ISH and IHC of a tissue chip. The function of circ1662 in CRC was evaluated by knocking down or overexpressing circ1662. MeRIP-qPCR, RIP-qPCR, and RNA pull-down were performed to determine the relationship between METTL3, circ1662, and YAP1. Results: A novel circRNA, circ1662, exhibited significantly higher expression in CRC tissues than paired normal tissues. High circ1662 expression was correlated with poor prognosis and tumor depth in patients with CRC. Functionally, circ1662 promoted CRC cell invasion and migration by controlling EMT in vitro and in vivo. Mechanistically, circ1662 directly bound to YAP1 and accelerated its nuclear accumulation to regulate the SMAD3 pathway. Additionally, circ1662 enhanced CRC invasion and migration depending on YAP1 and SMAD3. Interestingly, METTL3 induced circ1662 expression by binding its flanking sequences and installing m6A modifications. Clinically, circ1662 expression strongly correlated with METTL3 and YAP1 protein expression. Moreover, YAP1 expression was negatively correlated with SMAD3 expression. Conclusions: METTL3-induced circ1662 promoted CRC cell invasion and migration by accelerating YAP1 nuclear transport. This result implies that circ1662 is a new prognostic and therapeutic marker for CRC metastasis.

Cathepsin C promotes breast cancer lung metastasis by modulating neutrophil infiltration and neutrophil extracellular trap formation.

Lung metastasis is the major cause of breast cancer-related mortality. The neutrophil-associated inflammatory microenvironment aids tumor cells in metastatic colonization in lungs. Here, we show that tumor-secreted protease cathepsin C (CTSC) promotes breast-to-lung metastasis by regulating recruitment of neutrophils and formation of neutrophil extracellular traps (NETs). CTSC enzymatically activates neutrophil membrane-bound proteinase 3 (PR3) to facilitate interleukin-1ß (IL-1ß) processing and nuclear factor κB activation, thus upregulating IL-6 and CCL3 for neutrophil recruitment. In addition, the CTSC-PR3-IL-1ß axis induces neutrophil reactive oxygen species production and formation of NETs, which degrade thrombospondin-1 and support metastatic growth of cancer cells in the lungs. CTSC expression and secretion are associated with NET formation and lung metastasis in human breast tumors. Importantly, targeting CTSC with compound AZD7986 effectively suppresses lung metastasis of breast cancer in a mouse model. Overall, our findings reveal a mechanism of how tumor cells regulate neutrophils in metastatic niches and support CTSC-targeting approaches for cancer treatment.

Clinical characteristics of malignant melanoma in central China and predictors of metastasis.

Cutaneous malignant melanoma (MM) is the most malignant type of all skin neoplasms. There is wide variability in the characteristics of MM between patients of different races. The aim of the present study was to investigate the clinicopathological characteristics of patients with MM in central China and to assess the value of specific hematological and biochemical indices for predicting metastasis. The data of 167 patients with MM from the First Affiliated Hospital of Zhengzhou University (Henan, China) were retrospectively analyzed and compared with the data of patients with MM available from cBioPortal for Cancer Genomics. Following analysis of the clinicopathological characteristics of the 167 patients, the median overall survival time was 50 months, and the median disease-free survival time was 35 months. Albumin/D-dimer prognosis score (ADPS), lactate dehydrogenase, sex, T stage, tumor-node-metastasis stage, Breslow thickness, Clark level, histological type, growth phase, ulceration and metastasis were all significantly associated with prognosis. An ADPS of <341.01 was identified as an independent predictor of metastasis. The trial registration no. is 2018-LW-037 and this clinical trial was registered in the First Affiliated Hospital of Zhengzhou University Clinical Trial Registry in March 1, 2018.

The distribution of immune cells within combined hepatocellular carcinoma and cholangiocarcinoma predicts clinical outcome.

BACKGROUND: This study aimed to investigate the clinical relevance of the immune microenvironment in patients with combined hepatocellular carcinoma and cholangiocarcinoma (cHCC-ICC). PATIENTS AND METHODS: The density of tumor-infiltrating CD3+ , CD8+ , CD163+ , and Foxp3+ immune cells, as well as Programmed cell death 1, Programmed cell death-ligand 1, and Tumor necrosis factor receptor superfamily member 4, was measured in the peritumor liver, tumor invasive margin, and intratumor subregions of 56 cHCC-ICC by immunohistochemistry. The immune index was established to stratify patients. Prognostic significance of immune cell subsets and immune indices was evaluated. RESULTS: The distribution of immune cells was highly heterogeneous among different subregions of cHCC-ICC. As compared with the hepatocellular carcinoma (HCC) component, the lower density of CD8+ T cells and higher intensity of Foxp3+ Tregs and immune checkpoints in the intrahepatic cholangiocarcinoma (ICC) component may indicate a stronger immune evasive ability of ICC. Based on clustering classification or a combination of random forest and lasso-cox, two models of immune indices were established and both were identified as independent prognostic factors for cHCC-ICC patients. The selected immune variables in the immune prognostic models derived from both HCC and ICC subregions, indicating that the prognosis of cHCC-ICC patients was a complex interaction of both components. CONCLUSIONS: The immune contexture was heterogeneous among different subregions of cHCC-ICC patients and contributed differently to patient prognosis. Immune score based on the densities of immune cells might serve as a promising prognostic predictor for cHCC-ICC patients.

Global immune characterization of HBV/HCV-related hepatocellular carcinoma identifies macrophage and T-cell subsets associated with disease progression.

Diverse immune cells in the tumor microenvironment form a complex ecosystem, but our knowledge of their heterogeneity and dynamics within hepatocellular carcinoma (HCC) still remains limited. To assess the plasticity and phenotypes of immune cells within HBV/HCV-related HCC microenvironment at single-cell level, we performed single-cell RNA sequencing on 41,698 immune cells from seven pairs of HBV/HCV-related HCC tumors and non-tumor liver tissues. We combined bio-informatic analyses, flow cytometry, and multiplex immunohistochemistry to assess the heterogeneity of different immune cell subsets in functional characteristics, transcriptional regulation, phenotypic switching, and interactions. We identified 29 immune cell subsets of myeloid cells, NK cells, and lymphocytes with unique transcriptomic profiles in HCC. A highly complex immunological network was shaped by diverse immune cell subsets that can transit among different states and mutually interact. Notably, we identified a subset of M2 macrophage with high expression of CCL18 and transcription factor CREM that was enriched in advanced HCC patients, and potentially participated in tumor progression. We also detected a new subset of activated CD8+ T cells highly expressing XCL1 that correlated with better patient survival rates. Meanwhile, distinct transcriptomic signatures, cytotoxic phenotypes, and evolution trajectory of effector CD8+ T cells from early-stage to advanced HCC were also identified. Our study provides insight into the immune microenvironment in HBV/HCV-related HCC and highlights novel macrophage and T-cell subsets that could be further exploited in future immunotherapy.

Regulatory mechanisms and clinical perspectives of circRNA in digestive system neoplasms.

A new star, circular RNA (circRNA), is a class of noncoding RNA with a stable cyclic structure. Exonic circRNA mainly exists in the eukaryotic cytoplasm. Intronic circRNAs (ciRNA) and exonic circRNAs with introns (EIciRNA) are found in the nucleus. Recent evidences showed the functional diversity of circRNAs, which could be microRNA (miRNA) sponges, interact with protein or translate into small peptide. Due to the change of human eating habits, digestive cancer remains one of the most common cancers worldwide and it is prone to metastasis. Increasing studies have found a number of circRNAs using RNA sequencing technology and displayed double roles of circRNA in digestive cancer. In this review, we surveyed the biogenesis and regulation of circRNAs, discussed circRNA functions and clinical applications (especially circRNAs in exosome) in digestive cancers, which implied that circRNAs could be as potential biomarkers in diagnosis and treatment of digestive cancers in the future.

YAP1-induced MALAT1 promotes epithelial-mesenchymal transition and angiogenesis by sponging miR-126-5p in colorectal cancer.

Yes-associated protein 1 (YAP1) exerts significant effects in various malignancies. However, the oncogenic role of YAP1 remains controversial, and the mechanism by which YAP1 regulates non-coding RNAs is still largely unknown. The present study aimed to assess the effect of YAP1 on the malignant behaviors of colorectal carcinoma (CRC) and explore the underlying regulatory mechanism of the YAP1-MALAT1-miR-126-5p axis. YAP1 was highly expressed in CRC tissues as assessed by GSE20916 and its expression was negatively correlated with overall survival in 83 CRC cases. Meanwhile, YAP1 promoted proliferation, invasion, and migration in colon cancer cells, in vitro and in vivo. MALAT1 was obviously expressed, with differential expression of 11 lncRNAs in HCT116 cells after transfection with siYAP1 or si-Ctl. Based on bioinformatics prediction, immunoprecipitation (IP), and chromatin immunoprecipitation (ChIP), the interaction of YAP1 with TCF4/ß-catenin was regulated by MALAT1. Bioinformatics prediction, dual luciferase assay, RNA-IP, and RNA pull-down assay demonstrated that YAP1-induced MALAT1 promoted the expression of metastasis-associated molecules such as VEGFA, SLUG, and TWIST, by sponging miR-126-5p in CRC. These findings indicated that the YAP1-MALAT1-miR-126-5p axis could control angiogenesis and epithelial-mesenchymal transition in CRC, providing potential biomarkers and therapeutic targets for CRC.

MicroRNAs, long noncoding RNAs, and circular RNAs: potential tumor biomarkers and targets for colorectal cancer.

Noncoding RNAs (ncRNAs) can be divided into microRNAs (miRNAs), long noncoding RNAs (lncRNAs), circular RNAs (circRNAs), pRNAs, and tRNAs. Traditionally, miRNAs exert their biological function mainly through the inhibition of translation via the induction of target RNA transcript degradation. lncRNAs and circRNAs were once considered to have no potential to code proteins. Here, we will review the current knowledge on ncRNAs in relation to their origins, characteristics, and functions. We will also review how ncRNAs work as competitive endogenous RNA, gene transcription and expression regulators, and RNA-binding protein sponges in colorectal cancer (CRC). Notably, except for the abovementioned mechanisms, recent advances revealed that lncRNAs can also act as the precursor of miRNAs, and a small portion of lncRNAs and circRNAs was verified to have the potential to code proteins, providing new evidence for the significance of ncRNAs in CRC tumorigenesis and development.