RESUMEN
Cartilage, an important connective tissue, provides structural support to other body tissues, and serves as a cushion against impacts throughout the body. Found at the end of the bones, cartilage decreases friction and averts bone-on-bone contact during joint movement. Therefore, defects of cartilage can result from natural wear and tear, or from traumatic events, such as injuries or sudden changes in direction during sports activities. Overtime, these cartilage defects which do not always produce immediate symptoms, could lead to severe clinical pathologies. The emergence of induced pluripotent stem cells (iPSCs) has revolutionized the field of regenerative medicine, providing a promising platform for generating various cell types for therapeutic applications. Thus, chondrocytes differentiated from iPSCs become a promising avenue for non-invasive clinical interventions for cartilage injuries and diseases. In this review, we aim to highlight the current strategies used for in vitro chondrogenic differentiation of iPSCs and to explore their multifaceted applications in disease modeling, drug screening, and personalized regenerative medicine. Achieving abundant functional iPSC-derived chondrocytes requires optimization of culture conditions, incorporating specific growth factors, and precise temporal control. Continual improvements in differentiation methods and integration of emerging genome editing, organoids, and 3D bioprinting technologies will enhance the translational applications of iPSC-derived chondrocytes. Finally, to unlock the benefits for patients suffering from cartilage diseases through iPSCs-derived technologies in chondrogenesis, automatic cell therapy manufacturing systems will not only reduce human intervention and ensure sterile processes within isolator-like platforms to minimize contamination risks, but also provide customized production processes with enhanced scalability and efficiency.
Asunto(s)
Diferenciación Celular , Condrogénesis , Células Madre Pluripotentes Inducidas , Medicina de Precisión , Medicina Regenerativa , Humanos , Células Madre Pluripotentes Inducidas/citología , Células Madre Pluripotentes Inducidas/metabolismo , Medicina Regenerativa/métodos , Medicina de Precisión/métodos , Condrocitos/citología , Condrocitos/metabolismo , AnimalesRESUMEN
Onco-virotherapy is an emergent treatment for cancer based on viral vectors. The therapeutic activity is based on two different mechanisms including tumor-specific oncolysis and immunostimulatory properties. In this study, we evaluated onco-virotherapy in vitro responses on immunocompetent non-small cell lung cancer (NSCLC) patient-derived tumoroids (PDTs) and healthy organoids. PDTs are accurate tools to predict patient's clinical responses at the in vitro stage. We showed that onco-virotherapy could exert specific antitumoral effects by producing a higher number of viral particles in PDTs than in healthy organoids. In the present work, we used multiplex protein screening, based on proximity extension assay to highlight different response profiles. Our results pointed to the increase of proteins implied in T cell activation, such as IFN-γ following onco-virotherapy treatment. Based on our observation, oncolytic viruses-based therapy responders are dependent on several factors: a high PD-L1 expression, which is a biomarker of greater immune response under immunotherapies, and the number of viral particles present in tumor tissue, which is dependent to the metabolic state of tumoral cells. Herein, we highlight the use of PDTs as an alternative in vitro model to assess patient-specific responses to onco-virotherapy at the early stage of the preclinical phases.
Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas , Descubrimiento de Drogas , Neoplasias Pulmonares , Viroterapia Oncolítica , Proteómica , Humanos , Proteómica/métodos , Carcinoma de Pulmón de Células no Pequeñas/inmunología , Carcinoma de Pulmón de Células no Pequeñas/terapia , Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Neoplasias Pulmonares/inmunología , Neoplasias Pulmonares/terapia , Neoplasias Pulmonares/metabolismo , Viroterapia Oncolítica/métodos , Organoides , Virus Oncolíticos/inmunología , Proteoma , Biomarcadores de Tumor/metabolismo , Antígeno B7-H1/metabolismoRESUMEN
Leveraging the specificity of antibody to deliver cytotoxic agent into tumor, antibody-drug conjugates (ADCs) have become one of the hotspots in the development of anticancer therapies. Although significant progress has been achieved, there remain challenges to overcome, including limited penetration into solid tumors and potential immunogenicity. Fully human single-domain antibodies (UdAbs), with their small size and human nature, represent a promising approach for addressing these challenges. Carcinoembryonic antigen-related cell adhesion molecule 5 (CEACAM5) is a glycosylated cell surface protein that rarely expressed in normal adult tissues but overexpressed in diverse cancers, taking part in tumorigenesis, progression, and metastasis. In this study, we investigated the therapeutic potential of UdADC targeting CEACAM5. We performed biopanning in our library and obtained an antibody candidate B9, which bound potently and specifically to CEACAM5 protein (KD = 4.84 nM) and possessed excellent biophysical properties (low aggregation tendency, high homogeneity, and thermal stability). The conjugation of B9 with a potent cytotoxic agent, monomethyl auristatin E (MMAE), exhibited superior antitumor efficacy against CEACAM5-expressing human gastric cancer cell line MKN-45, human pancreatic carcinoma cell line BxPC-3 and human colorectal cancer cell line LS174T with IC50 values of 38.14, 25.60, and 101.4 nM, respectively. In BxPC-3 and MKN-45 xenograft mice, administration of UdADC B9-MMAE (5 mg/kg, i.v.) every 2 days for 4 times markedly inhibited the tumor growth without significant change in body weight. This study may have significant implications for the design of next-generation ADCs.
Asunto(s)
Antineoplásicos , Inmunoconjugados , Anticuerpos de Dominio Único , Humanos , Animales , Ratones , Línea Celular Tumoral , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Inmunoconjugados/farmacología , Inmunoconjugados/uso terapéutico , Moléculas de Adhesión Celular , Citotoxinas , Ensayos Antitumor por Modelo de Xenoinjerto , Antígeno Carcinoembrionario , Proteínas Ligadas a GPIRESUMEN
This work describes a patient-derived tumoroid model (PDTs) to support precision medicine in lung oncology. The use of human adipose tissue-derived microvasculature and patient-derived peripheral blood mononuclear cells (PBMCs) permits to achieve a physiologically relevant tumor microenvironment. This study involved ten patients at various stages of tumor progression. The vascularized, immune-infiltrated PDT model could be obtained within two weeks, matching the requirements of the therapeutic decision. Histological and transcriptomic analyses confirmed that the main features from the original tumor were reproduced. The 3D tumor model could be used to determine the dynamics of response to antiangiogenic therapy and platinum-based chemotherapy. Antiangiogenic therapy showed a significant decrease in vascular endothelial growth factor (VEGF)-A expression, reflecting its therapeutic effect in the model. In an immune-infiltrated PDT model, chemotherapy showed the ability to decrease the levels of lymphocyte activation gene-3 protein (LAG-3), B and T lymphocyte attenuator (BTLA), and inhibitory receptors of T cells functions.
RESUMEN
Reconstructing the meniscus is not currently possible due to its intricate and heterogeneous structure. In this forum, we first discuss the shortcomings of current clinical strategies in meniscus repair. Then, we describe a new promising cell-based, ink-free 3D biofabrication technology to produce tailor-made large-scale functional menisci.
Asunto(s)
Bioimpresión , Menisco , Ingeniería de Tejidos , Andamios del Tejido/químicaRESUMEN
Radiation therapy and platinum-based chemotherapy are common treatments for lung cancer patients. Several factors are considered for the low overall survival rate of lung cancer, such as the patient's physical state and the complex heterogeneity of the tumor, which leads to resistance to the treatment. Consequently, precision medicines are needed for the patients to improve their survival and their quality of life. Until now, no patient-derived tumoroid model has been reported to predict the efficiency of radiation therapy in non-small-cell lung cancer. Using our patient-derived tumoroid model, we report that this model could be used to evaluate the efficiency of radiation therapy and cisplatin-based chemotherapy in non-small-cell lung cancer. In addition, these results can be correlated to clinical outcomes of patients, indicating that this patient-derived tumoroid model can predict the response to radiotherapy and chemotherapy in non-small-cell lung cancer.
RESUMEN
Organoid models have the potential to recapitulate the biological and pharmacotypic features of parental tumors. Nevertheless, integrative pharmaco-proteogenomics analysis for drug response features and biomarker investigation for precision therapy of patients with liver cancer are still lacking. We established a patient-derived liver cancer organoid biobank (LICOB) that comprehensively represents the histological and molecular characteristics of various liver cancer types as determined by multiomics profiling, including genomic, epigenomic, transcriptomic, and proteomic analysis. Proteogenomic profiling of LICOB identified proliferative and metabolic organoid subtypes linked to patient prognosis. High-throughput drug screening revealed distinct response patterns of each subtype that were associated with specific multiomics signatures. Through integrative analyses of LICOB pharmaco-proteogenomics data, we identified the molecular features associated with drug responses and predicted potential drug combinations for personalized patient treatment. The synergistic inhibition effect of mTOR inhibitor temsirolimus and the multitargeted tyrosine kinase inhibitor lenvatinib was validated in organoids and patient-derived xenografts models. We also provide a user-friendly web portal to help serve the biomedical research community. Our study is a rich resource for investigation of liver cancer biology and pharmacological dependencies and may help enable functional precision medicine.
Asunto(s)
Neoplasias Hepáticas , Proteogenómica , Humanos , Proteómica , Medicina de Precisión , Neoplasias Hepáticas/tratamiento farmacológico , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patología , OrganoidesRESUMEN
Organoids have attracted great interest for disease modelling, drug discovery and development, and tissue growth and homeostasis investigations. However, lack of standards for quality control has become a prominent obstacle to limit their translation into clinic and other applications. "Human intestinal organoids" is the first guideline on human intestinal organoids in China, jointly drafted and agreed by the experts from the Chinese Society for Cell Biology and its branch society: the Chinese Society for Stem Cell Research. This standard specifies terms and definitions, technical requirements, test methods, inspection rules for human intestinal organoids, which is applicable to quality control during the process of manufacturing and testing of human intestinal organoids. It was originally released by the Chinese Society for Cell Biology on 24 September 2022. We hope that the publication of this standard will guide institutional establishment, acceptance and execution of proper practical protocols and accelerate the international standardization of human intestinal organoids for applications.
RESUMEN
Epithelial regeneration is critical for barrier maintenance and organ function after intestinal radiation injury. Accumulating evidence indicates that the interleukin family members play critical roles in intestinal stem-cell-mediated epithelial regeneration. However, little is known about the relationship between interleukin 33 (IL-33)/ST2 axis and intestinal regeneration after radiation injury. We demonstrate here that IL-33 expression significantly increased after radiation treatment. Deficiency of IL-33/ST2 promotes intestinal epithelial regeneration, resulting in a reduction of mortality during radiation-induced intestine injury. Using ex vivo organoid cultures, we show that recombinant IL-33 promotes intestinal stem cell differentiation. Mechanistically, the effects of IL-33 were mediated by activation of transforming growth factor-ß signaling. Our findings reveal a fundamental mechanism by which IL-33 is able to regulate the intestinal crypt regeneration after tissue damage.
Asunto(s)
Interleucina-33 , Traumatismos por Radiación , Humanos , Interleucina-33/metabolismo , Proteína 1 Similar al Receptor de Interleucina-1/metabolismo , Intestinos , Traumatismos por Radiación/terapia , Células Madre , Factor de Crecimiento Transformador beta/metabolismoRESUMEN
Introduction: Most advanced colorectal cancers are aggressive, and there is a lack of effective methods for selecting appropriate anticancer regimens. Patient-derived organoids (PDOs) have emerged as preclinical platforms for modeling clinical responses to cancer therapy. Methods: In this study, we successfully constructed a living biobank with 42 organoids derived from primary and metastatic lesions of metastatic colorectal cancer patients. Tumor tissue was obtained from patients undergoing surgical resection of the primary or metastatic lesion and then used to establish PDOs. Immunohistochemistry (IHC) and drug sensitivity assays were performed to analyze the properties of these organoids. Results: The mCRC organoids were successfully established with an 80% success rate. The PDOs maintained the genetic and phenotypic heterogeneity of their parental tumors. The IC50 values of5-fluorouracil (5-FU), oxaliplatin, and irinotecan (CPT11) were determined for mCRC organoids using drug sensitivity assays. The in vitro chemosensitivity data revealed the potential value of PDOs for clinical applications in predicting chemotherapy response and clinical outcomes in mCRC patients. Discussion: In summary, the PDO model is an effective platform for in vitro assessment of patient-specific drug sensitivity, which can guide personalized treatment decisions for patients with end-stage CRC.
RESUMEN
Intestinal cancer is one of the most frequent and lethal types of cancer. Modeling intestinal cancer using organoids has emerged in the last decade. Human intestinal cancer organoids are physiologically relevant in vitro models, which provides an unprecedented opportunity for fundamental and applied research in colorectal cancer. "Human intestinal cancer organoids" is the first set of guidelines on human intestinal organoids in China, jointly drafted and agreed by the experts from the Chinese Society for Cell Biology and its branch society: the Chinese Society for Stem Cell Research. This standard specifies terms and definitions, technical requirements, test methods for human intestinal cancer organoids, which apply to the production and quality control during the process of manufacturing and testing of human intestinal cancer organoids. It was released by the Chinese Society for Cell Biology on 24 September 2022. We hope that the publication of this standard will guide institutional establishment, acceptance and execution of proper practocal protocols, and accelerate the international standardization of human intestinal cancer organoids for clinical development and therapeutic applications.
RESUMEN
Immunotherapy as a rapidly developing therapeutic approach has revolutionized cancer treatment and revitalized the field of tumor immunology research. 3D in vitro models are emerging as powerful tools considering their feature to maintain tumor cells in a near-native state and have been widely applied in oncology research. The novel 3D culture methods including the co-culture of organoids and immune cells, ALI culture, 3D-microfluidic culture and 3D-bioprinting offer new approaches for tumor immunology study and can be applied in many fields such as personalized treatment, immunotherapy optimizing and adoptive cell therapy. In this review, we introduce commonly used 3D in vitro models and summarize their applications in different aspects of tumor immunology research. We also provide a preliminary analysis of the current shortcomings of these models and the outlook of future development.
Asunto(s)
Neoplasias , Humanos , Neoplasias/patología , Técnicas de Cocultivo , Oncología Médica , Organoides , Inmunoterapia , Microambiente TumoralRESUMEN
Antibody-drug conjugates (ADC) using DNA topoisomerase I inhibitor DXd/SN-38 have transformed cancer treatment, yet more effective ADCs are needed for overcoming resistance. We have designed an ADC class using a novel self-immolative T moiety for traceless conjugation and release of exatecan, a more potent topoisomerase I inhibitor with less sensitivity to multidrug resistance (MDR). Characterized by enhanced therapeutic indices, higher stability, and improved intratumoral pharmacodynamic response, antibody-T moiety-exatecan conjugates targeting HER2, HER3, and TROP2 overcome the intrinsic or treatment resistance of equivalent DXd/SN-38 ADCs in low-target-expression, large, and MDR+ tumors. T moiety-exatecan ADCs display durable antitumor activity in patient-derived xenograft and organoid models representative of unmet clinical needs, including EGFR ex19del/T790M/C797S triple-mutation lung cancer and BRAF/KRAS-TP53 double-mutant colon cancer, and show synergy with PARP/ATR inhibitor and anti-PD-1 treatment. High tolerability of the T moiety-exatecan ADC class in nonhuman primates supports its potential to expand the responding patient population and tumor types beyond current ADCs. SIGNIFICANCE: ADCs combining a novel self-immolative moiety and topoisomerase I inhibitor exatecan as payload show deep and durable response in low-target-expressing and MDR+ tumors resistant to DXd/SN-38 ADCs without increasing toxicity. This new class of ADCs has the potential to benefit an additional patient population beyond current options. See related commentary by Gupta et al., p. 817. This article is highlighted in the In This Issue feature, p. 799.
Asunto(s)
Antineoplásicos , Inmunoconjugados , Neoplasias Pulmonares , Animales , Humanos , Inhibidores de Topoisomerasa I/farmacología , Inhibidores de Topoisomerasa I/uso terapéutico , Irinotecán , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/genética , Línea Celular Tumoral , Mutación , Inhibidores de Proteínas Quinasas , Antineoplásicos/farmacología , Inmunoconjugados/farmacología , Inmunoconjugados/uso terapéutico , Receptor ErbB-2 , ColonRESUMEN
Previous studies show increased sensitivity of older mice (28-29 months) compared with young adult mice (3 months, possessing a mature immune system) to radiation-induced GI lethality. Age-dependent lethality was associated with higher levels of apoptotic stem cells in small intestinal crypts that correlated with sphingomyelinase activity, a source of pro-apoptotic ceramide. The objective of this study is to determine whether the cycling crypt base columnar cells (CBCs) in aging animals are specifically more sensitive to radiation effects than the CBCs in young adult mice, and to identify factors that contribute to increased radiosensitivity. Mortality induced by subtotal body radiation was assessed at different doses (13 Gy, 14 Gy, and 15 Gy) in young adult mice versus older mice. Each dose was evaluated for the occurrence of lethal GI syndrome. A higher death rate due to radiation-induced GI syndrome was observed in older mice as compared with young adult mice: 30 vs. 0% at 13 Gy, 90 vs. 40% at 14 Gy, and 100 vs. 60% at 15 Gy. Radiation-induced damage to crypts was determined by measuring crypt regeneration (H&E staining, Ki67 expression), CBC biomarkers (lgr5 and ascl2), premature senescence (SA-ß-gal activity), and apoptosis of CBCs. At all three doses, crypt microcolony survival assays showed that the older mice had fewer regenerating crypts at 3.5 days post-radiation treatment. Furthermore, in the older animals, baseline CBCs numbers per circumference were significantly decreased, correlating with an elevated apoptotic index. Analysis of tissue damage showed an increased number of senescent CBCs per crypt circumference in older mice relative to younger mice, where the latter was not significantly affected by radiation treatment. It is concluded that enhanced sensitivity to radiation-induced GI syndrome and higher mortality in older mice can be attributed to a decreased capacity to regenerate crypts, presumably due to increased apoptosis and senescence of CBCs.
RESUMEN
Adding irinotecan to neoadjuvant chemoradiotherapy (nCRT) in locally advanced rectal cancer (LARC) increases the pathologic complete response (pCR) rate but brings more toxicities. Robust biomarkers to predict response to irinotecan-based nCRT are extremely necessary for selecting the right patients. Our previous study suggests that patient-derived tumor organoids (PDTOs) sensitivity to chemoradiotherapy matches patient responses. In this study, we investigated whether PDTOs sensitivity to irinotecan can predict complete response (CR) and survival. Eligible patients receiving irinotecan-based nCRT between April 5, 2017 and December 11, 2020 were enrolled in the training cohort (n = 91) for response prediction and survival analysis. Patients receiving nCRT between February 21, 2021 and September 17, 2021 were included in the validation cohort (n = 27). Predictive performances of irinotecan organoid size ratio (OSR) for CR or pCR were evaluated. The irinotecan-sensitive groups had higher response rates compared with the insensitive groups (training cohort: 71.8% vs 24.4%, P < .0001; validation cohort, 81.8% vs 18.8%, P = .002). Moreover, the irinotecan-sensitive group had higher rates of 3-year disease-free survival (DFS: 71.6% vs 55.5%, P = .034) and distant metastasis-free survival (DMFS, 77.9% vs 57.2%, P = .015) than the irinotecan-insensitive group. 5-FU and irradiation sensitivities failed to predict 3-year DFS (5-FU: 65.4% vs 61.9%, P = .643; irradiation: 84.8% vs 57.8%; P = .072). Performances of irinotecan OSR to predict CR or pCR were good in the training cohort (CR: AUC = 0.828; 95% CI = 0.723-0.932; pCR: AUC = 0.864; 95% CI = 0.759-0.961). The validation showed robust predictive ability (CR: AUC = 0.796, 95% CI = 0.5974-0.9952; pCR: AUC = 0.917, 95% CI = 0.7921-1.0000). Irinotecan sensitivity in PDTOs was a predictive and prognostic factor in LARC.
Asunto(s)
Neoplasias Primarias Secundarias , Neoplasias del Recto , Humanos , Terapia Neoadyuvante , Irinotecán , Neoplasias del Recto/patología , Estudios Retrospectivos , Quimioradioterapia , Fluorouracilo , Organoides/patologíaRESUMEN
There is no effective method to predict chemotherapy response and postoperative prognosis of colorectal cancer liver metastasis (CRLM) patients. Patient-derived organoid (PDO) has become an important preclinical model. Herein, a living biobank with 50 CRLM organoids derived from primary tumors and paired liver metastatic lesions is successfully constructed. CRLM PDOs from the multiomics levels (histopathology, genome, transcriptome and single-cell sequencing) are comprehensively analyzed and confirmed that this organoid platform for CRLM could capture intra- and interpatient heterogeneity. The chemosensitivity data in vitro reveal the potential value of clinical application for PDOs to predict chemotherapy response (FOLFOX or FOLFIRI) and clinical prognosis of CRLM patients. Taken together, CRLM PDOs can be utilized to deliver a potential application for personalized medicine.
Asunto(s)
Antineoplásicos , Neoplasias Colorrectales , Neoplasias Hepáticas , Humanos , Organoides , Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/patología , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Neoplasias Hepáticas/tratamiento farmacológico , PronósticoRESUMEN
Patient-derived tumoroid (PDT) has been developed and used for anti-drug screening in the last decade. As compared to other existing drug screening models, a PDT-based in vitro 3D cell culture model could preserve the histological and mutational characteristics of their corresponding tumors and mimic the tumor microenvironment. However, few studies have been carried out to improve the microvascular network connecting the PDT and its surrounding microenvironment, knowing that poor tumor-selective drug transport and delivery is one of the major reasons for both the failure of anti-cancer drug screens and resistance in clinical treatment. In this study, we formed vascularized PDTs in six days using multiple cell types which maintain the histopathological features of the original cancer tissue. Furthermore, our results demonstrated a vascular network connecting PDT and its surrounding microenvironment. This fast and promising PDT model opens new perspectives for personalized medicine: this model could easily be used to test all therapeutic treatments and could be connected with a microfluidic device for more accurate drug screening.
RESUMEN
BACKGROUND: Organoids are three-dimensional structures that closely recapitulate tissue architecture and cellular composition, thereby holding great promise for organoid-based drug screening. Although growing in three-dimensional provides the possibility for organoids to recapitulate main features of corresponding tissues, it makes it incommodious for imaging organoids in two-dimensional and identifying surviving organoids from surrounding dead cells after organoids being treated by irradiation or chemotherapy. Therefore, significant work remains to establish high-quality controls to standardize organoid analyses and make organoid models more reproducible. METHODS: In this study, the Z-stack imaging technique was used for the imaging of three-dimensional organoids to gather all the organoids' maximum cross sections in one imaging. The combination of live cell staining fluorescent dye Calcein-AM and ImageJ assessment was used to analyze the survival of organoids treated by irradiation or chemotherapy. RESULTS: We have established a novel quantitative high-throughput imaging assay that harnesses the scalability of organoid cultures. Using this assay, we can capture organoid growth over time, measure multiple whole-well organoid readouts, and show the different responses to drug treatments. CONCLUSIONS: In summary, combining the Z-stack imaging technique and fluorescent labeling methods, we established an assay for the imaging and analysis of three-dimensional organoids. Our data demonstrated the feasibility of using organoid-based platforms for high-throughput drug screening assays.
Asunto(s)
Ensayos Analíticos de Alto Rendimiento , Organoides , Evaluación Preclínica de MedicamentosRESUMEN
Recent data establish a logarithmic expansion of leucine rich repeat containing G protein coupled receptor 5-positive (Lgr5+) colonic epithelial stem cells (CESCs) in human colorectal cancer (CRC). Complementary studies using the murine 2-stage azoxymethane-dextran sulfate sodium (AOM-DSS) colitis-associated tumor model indicate early acquisition of Wnt pathway mutations drives CESC expansion during adenoma progression. Here, subdivision of the AOM-DSS model into in vivo and in vitro stages revealed DSS induced physical separation of CESCs from stem cell niche cells and basal lamina, a source of Wnt signals, within hours, disabling the stem cell program. While AOM delivery in vivo under non-adenoma-forming conditions yielded phenotypically normal mucosa and organoids derived thereof, niche injury ex vivo by progressive DSS dose escalation facilitated outgrowth of Wnt-independent dysplastic organoids. These organoids contained 10-fold increased Lgr5+ CESCs with gain-of-function Wnt mutations orthologous to human CRC driver mutations. We posit CRC originates by niche injury-induced outgrowth of normally suppressed mutated stem cells, consistent with models of adaptive oncogenesis.