Neuroendocrine Research Articles

EHMT2-mediated transcriptional reprogramming drives neuroendocrine transformation in non–small cell lung cancer

The transformation of lung adenocarcinoma to small cell lung cancer (SCLC) is a recognized resistance mechanism and a hindrance to therapies using epidermal growth factor receptor tyrosine kinase inhibitors (TKIs). The paucity of pretranslational/posttranslational clinical samples limits the deeper understanding of resistance mechanisms and the exploration of effective therapeutic strategies. Here, we developed preclinical neuroendocrine (NE) transformation models. Next, we identified a transcriptional reprogramming mechanism that drives resistance to erlotinib in NE transformation cell lines and cell-derived xenograft mice. We observed the enhanced expression of genes involved in the EHMT2 and WNT/β-catenin pathways. In addition, we demonstrated that EHMT2 increases methylation of the SFRP1 promoter region to reduce SFRP1 expression, followed by activation of the WNT/β-catenin pathway and TKI-mediated NE transformation. Notably, the similar expression alterations of EHMT2 and SFRP1 were observed in transformed SCLC samples obtained from clinical patients. Importantly, suppression of EHMT2 with selective inhibitors restored the sensitivity of NE transformation cell lines to erlotinib and delayed resistance in cell-derived xenograft mice. We identify a transcriptional reprogramming process in NE transformation and provide a potential therapeutic target for overcoming resistance to erlotinib.

Neuroendocrine Breast Carcinoma: Interesting Images of an Underdiagnosed Entity.

Breast cancer is the most common type of cancer of the female gender. A rare subtype of breast cancer is the invasive breast carcinoma (IBC) with neuroendocrine (NE) differentiation. Its incident is believed to be 0.1% to 5% of all breast cancers. We report a rare case of a 66-year old woman who presented with an isolated nodule of the left breast. The patient underwent modified radical mastectomy. Pathology revealed invasive breast carcinoma with neuroendocrine differentiation. Invasive breast carcinoma is an extremely rare group of neoplasms, the exact frequency of which cannot be determined with current data. Therefore, it is necessary for future studies to focus on the pathophysiology of this subtype of breast cancer and on the potential therapeutic approaches.

Pulmonary neuroendocrine tumors : Current review

Neuroendocrine neoplasms of the lung are aheterogenous tumor group. The pathological classification comprises diffuse idiopathic pulmonary neuroendocrine cell hyperplasia, classic neuroendocrine tumors, and neuroendocrine carcinoma. Classic neuroendocrine tumors include typical and atypical carcinoid tumors. Imaging plays an important role in diagnosis and can help in identifying the tumor biology. Overall, this tumor group is rare, comprising less than 2% of all thoracic tumors. In the current review, the various tumors are presented and important aspects regarding pathological classification, imaging modalities, and treatment are described.

FREnch National Cohort of neuroendocrine cell Hyperplasia of Infancy (FRENCHI): Long-term consequences and risk factors of low body mass index

FREnch National Cohort of neuroendocrine cell Hyperplasia of Infancy (FRENCHI): Long-term consequences and risk factors of low body mass index

CRACD loss induces neuroendocrine cell plasticity of lung adenocarcinoma

Tumor cell plasticity contributes to intratumoral heterogeneity and therapy resistance. Through cell plasticity, some lung adenocarcinoma (LUAD) cells transform into neuroendocrine (NE) tumor cells. However, the mechanisms of NE cell plasticity remain unclear. CRACD (capping protein inhibiting regulator of actin dynamics), a capping protein inhibitor, is frequently inactivated in cancers. CRACD knockout (KO) is sufficient to de-repress NE-related gene expression in the pulmonary epithelium and LUAD cells. In LUAD mouse models, Cracd KO increases intratumoral heterogeneity with NE gene expression. Single-cell transcriptomic analysis showed that Cracd KO-induced NE cell plasticity is associated with cell de-differentiation and stemness-related pathway activation. The single-cell transcriptomic analysis of LUAD patient tumors recapitulates that the distinct LUAD NE cell cluster expressing NE genes is co-enriched with impaired actin remodeling. This study reveals the crucial role of CRACD in restricting NE cell plasticity that induces cell de-differentiation of LUAD.

PCDHGC3 hypermethylation as a potential biomarker of intestinal neuroendocrine carcinomas.

Neuroendocrine neoplasms (NENs) encompass tumors arising from neuroendocrine cells in various organs, including the gastrointestinal tract, pancreas, adrenal gland, and paraganglia. Despite advancements, accurately predicting the aggressiveness of gastroenteropancreatic (GEP) NENs based solely on pathological data remains challenging, thereby limiting optimal clinical management. Our previous research unveiled a crucial link between hypermethylation of the protocadherin PCDHGC3 gene and neuroendocrine tumors originating from the paraganglia and adrenal medulla. This epigenetic alteration was associated with increased metastatic potential and succinate dehydrogenase complex (SDH) dysfunction. Expanding upon this discovery, the current study explored PCDHGC3 gene methylation within the context of GEP-NENs in a cohort comprising 34 cases. We uncovered promoter hypermethylation of PCDHGC3 in 29% of GEP-NENs, with a significantly higher prevalence in gastrointestinal (GI) neuroendocrine carcinomas (NECs) compared with both pancreatic (Pan) NECs and neuroendocrine tumors (NETs) of GI and Pan origin. Importantly, these findings were validated in one of the largest multi-center GEP-NEN cohorts. Mechanistic analysis revealed that PCDHGC3 hypermethylation was not associated with SDH mutations or protein loss, indicating an SDH-independent epigenetic mechanism. Clinically, PCDHGC3 hypermethylation emerged as a significant prognostic factor, correlating with reduced overall survival rates in both patient cohorts. Significantly, whereas PCDHGC3 hypermethylation exhibited a strong correlation with TP53 somatic mutations, a hallmark of NEC, its predictive value surpassed that of TP53 mutations, with an area under the curve (AUC) of 0.95 (95% CI 0.83-1.0) for discriminating GI-NECs from GI-NETs, highlighting its superior predictive performance. In conclusion, our findings position PCDHGC3 methylation status as a promising molecular biomarker for effectively stratifying patients with GI-NENs. This discovery has the potential to advance patient care by enabling more precise risk assessments and tailored treatment strategies. © 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Asthma: a New Approach to the Bronchial Epithelium

The bronchial epithelium serves as a critical defense line against environmental insults, acting not merely as a barrier but as a complex, dynamic system enriched with diverse cell types such as ciliated cells, goblet cells, and basal cells. Recent advancements in single-cell ribonucleic acid (RNA) sequencing have further unveiled the complexity of this layer by identifying additional cell types like ionocytes, neuroendocrine cells, tuft cells, deuterosomal cells, club cells and mucus ciliated cells. These cells collectively maintain respiratory health through various mechanisms including the mucociliary escalator, mucus production, airway repair, and immune modulation. Disruptions in the epithelial barrier can lead to respiratory diseases like asthma, highlighting the importance of understanding these intricate cellular relationships for developing targeted therapies. This epithelial complexity is crucial for pulmonary homeostasis and the pathogenesis of asthma, where abnormal epithelial remodeling and dysfunction are central. The identification of a novel mucous ciliated cell state in asthma, co-expressing genes associated with both ciliated and goblet cells, offers new insights into the disease’s pathogenesis and therapeutic targets. The epithelial barrier’s integrity, maintained by tight junctions and adherents’ junctions, is essential for protecting the underlying tissue from environmental threats. However, in asthma, this barrier is compromised, leading to increased allergen permeability, airway hyperresponsiveness, inflammation, and remodeling. Despite advances, the need for novel concepts in asthma pathogenesis remains, particularly to address the limitations of the current T helper 2-dominant paradigm in explaining the connection between airway inflammation and remodeling. Understanding the molecular mechanisms underlying epithelial barrier dysfunction could pave the way for novel asthma treatments focused on enhancing barrier integrity, ultimately improving patient outcomes.

AMPK inhibits voltage-gated calcium channel-current in rat chromaffin cells

Metabolic changes are critical in the regulation of Ca2+ influx in central and peripheral neuroendocrine cells. To study the regulation of L-type Ca2+ channels by AMPK we used biochemical reagents and ATP/glucose-concentration manipulations in rat chromaffin cells. AICAR and Compound-C, at low concentration, significantly induce changes in L-type Ca2+ channel-current amplitude and voltage dependence. Remarkably, an overlasting decrease in the channel-current density can be induced by lowering the intracellular level of ATP. Accordingly, Ca2+ channel-current density gradually diminishes by decreasing the extracellular glucose concentration. By using immunofluorescence, a decrease in the expression of CaV1.2 is observed while decreasing extracellular glucose, suggesting that AMPK reduces the number of functional Ca2+ channels into the plasma membrane. Together, these results support for the first time the dependence of metabolic changes in the maintenance of Ca2+ channel-current by AMPK. They reveal a key step in Ca2+ influx in secretory cells.

Effective suppression of Ih and INa caused by capsazepine, known to be a blocker of TRPV1 receptor

A synthetic inhibitor of capsaicin-induced TRPV1 channel activation is called capsazepine (CPZ). In this study, we aimed to explore the effects of CPZ on hyperpolarization-activated cationic current (Ih) and voltage-gated Na + current (INa) in pituitary tumor (GH3) cells. Through patch-clamp recordings, we found that CPZ concentration-dependently inhibited Ih amplitude and slowed its activation time course. The IC50 and KD values were 3.1 and 3.16 μM, respectively. CPZ also shifted the steady-state activation curve of Ih towards a more hyperpolarized potential. However, there was no change in the gating charge of the curve. A modified Markovian model predicted the CPZ-induced decrease in the voltage-dependent hysteresis of Ih. CPZ suppressed INa in GH3 cells, without altering its activation or inactivation time course. Additionally, exposure to CPZ reduced spontaneous firing. These findings suggest that CPZ’s inhibitory effects on Ih and INa are direct and not dependent on vanilloid receptor binding. This could provide light on an unidentified ionic mechanism influencing the membrane excitability of neurons and endocrine or neuroendocrine cells in vivo.

Clinical management of typical and atypical carcinoids/neuroendocrine tumors in ENETS centres of excellence (CoE): Survey from the ENETS lung NET task force.

Lung carcinoid tumours are neuroendocrine neoplasms originating from the bronchopulmonary tract's neuroendocrine cells, accounting for only 1%-3% of all lung cancers but 30% of all neuroendocrine tumours. The incidence of lung carcinoids, both typical and atypical, has been increasing over the years due to improved diagnostic methods and increased awareness among clinicians and pathologists. The most recent WHO classification includes a subgroup of lung carcinoids with atypical morphology and higher mitotic count and/or Ki67 labelling index. Despite appropriate surgery, the 5-year survival rate for atypical carcinoids barely exceeds 50%-70%. The role of adjuvant therapy in lung carcinoids is not well-defined, and clinical decisions are generally based on the presence of high-risk features. Long-term follow-up is essential to monitor for recurrence, although the optimal follow-up protocol remains unclear. To address the lack of consensus in clinical management decisions, the European Neuroendocrine Tumor Society (ENETS) initiated a survey among 20 expert centres. The survey identified varied opinions on approaches to imaging, surgery, use of adjuvant therapy, and follow-up protocols. Notably, the absence of dedicated multidisciplinary lung neuroendocrine tumour boards in some centres was evident. Experts agreed on the need for a prospective adjuvant trial in high-risk patients, emphasizing the feasibility of such a study. In conclusion, the study highlights the need for a more uniform adoption of existing guidelines in the management of lung carcinoid tumours and emphasizes the importance of international collaboration to advance research and patient care. Close collaboration between healthcare providers and patients is vital for effective long-term surveillance and management of these rare tumours.

Cell scientist to watch – Bhavani Shankar Sahu

ABSTRACT Bhavani Shankar Sahu is an Associate Professor at the National Brain Research Centre (NBRC) in Manesar, India. He completed his PhD in cell biology and molecular genetics at the Indian Institute of Technology Madras, studying links between neuroendocrine function and metabolic disease. Inspired to better understand fundamental mechanisms of neuropeptide secretion, he then completed postdoctoral research in Prof. Margaret Robinson's lab at the University of Cambridge, UK and with Prof. Alessandro Bartolomucci at the University of Minnesota and University of California San Diego, USA. In 2019, he returned to India to start his own lab at the NBRC, where he and his team investigate the biology of exocytosis in neurons and neuroendocrine cells from the molecular to the physiological level. We spoke with Bhavani over Zoom about his career journey, mentorship philosophy and enthusiasm for science outreach.

Different lymph node staging systems for predicting the prognosis of colorectal neuroendocrine neoplasms.

Colorectal neuroendocrine neoplasms (NENs) are a rare malignancy that primarily arises from the diffuse distribution of neuroendocrine cells in the colon and rectum. Previous studies have pointed out that the status of lymph node may be used to predict the prognosis. To investigate the predictive values of lymph node ratio (LNR), positive lymph node (PLN), and log odds of PLNs (LODDS) staging systems on the prognosis of colorectal NENs treated surgically, and compare their predictive values. This cohort study included 895 patients with colorectal NENs treated surgically from the Surveillance, Epidemiology, and End Results database. The endpoint was mortality of patients with colorectal NENs treated surgically. X-tile software was utilized to identify most suitable thresholds for categorizing the LNR, PLN, and LODDS. Participants were selected in a random manner to form training and testing sets. The prognosis of surgically treating colorectal NENs was examined using multivariate cox analysis to assess the associations of LNR, PLN, and LODDS with the prognosis of colorectal NENs. C-index was used for assessing the predictive effectiveness. We conducted a subgroup analysis to explore the different lymph node staging systems' predictive values. After adjusting all confounding factors, PLN, LNR and LODDS staging systems were linked with mortality in patients with colorectal NENs treated surgically (P < 0.05). We found that LODDS staging had a higher prognostic value for patients with colorectal NENs treated surgically than PLN and LNR staging systems. Similar results were obtained in the different G staging subgroup analyses. Furthermore, the area under the receiver operating characteristic curve values for LODDS staging system remained consistently higher than those of PLN or LNR, even at the 1-, 2-, 3-, 4-, 5- and 6-year follow-up periods. LNR, PLN, and LODDS were found to significantly predict the prognosis of patients with colorectal NENs treated surgically.

CYB561 supports the neuroendocrine phenotype in castration-resistant prostate cancer.

Castration-resistant prostate cancer (CRPC) is associated with resistance to androgen deprivation therapy, and an increase in the population of neuroendocrine (NE) differentiated cells. It is hypothesized that NE differentiated cells secrete neuropeptides that support androgen-independent tumor growth and induce aggressiveness of adjacent proliferating tumor cells through a paracrine mechanism. The cytochrome b561 (CYB561) gene, which codes for a secretory vesicle transmembrane protein, is constitutively expressed in NE cells and highly expressed in CRPC. CYB561 is involved in the α-amidation-dependent activation of neuropeptides, and contributes to regulating iron metabolism which is often dysregulated in cancer. These findings led us to hypothesize that CYB561 may be a key player in the NE differentiation process that drives the progression and maintenance of the highly aggressive NE phenotype in CRPC. In our study, we found that CYB561 expression is upregulated in metastatic and NE prostate cancer (NEPC) tumors and cell lines compared to normal prostate epithelia, and that its expression is independent of androgen regulation. Knockdown of CYB561 in androgen-deprived LNCaP cells dampened NE differentiation potential and transdifferentiation-induced increase in iron levels. In NEPC PC-3 cells, depletion of CYB561 reduced the secretion of growth-promoting factors, lowered intracellular ferrous iron concentration, and mitigated the highly aggressive nature of these cells in complementary assays for cancer hallmarks. These findings demonstrate the role of CYB561 in facilitating transdifferentiation and maintenance of NE phenotype in CRPC through its involvement in neuropeptide biosynthesis and iron metabolism pathways.

Ultrastructural Changes of Neuroendocrine Pheochromocytoma Cell Line PC-12 Exposed In Vitro to Rotenone.

Rotenone is a pesticide used in research for its ability to induce changes similar, in vivo and in vitro, to those observed in Parkinson's disease (PD). This includes a selective death of dopaminergic neurons in the substantia nigra. Nonetheless, the precise mechanism through which rotenone modifies structure and function of neurons remains unclear. The PC12 cells closely resemble dopamine terminal neurons. This makes it a preferred model for studying the morphology of central dopamine neurons and predicting neurotoxicity. In this paper, we investigated the effects of 0.5 µM rotenone for 24-48 h on PC12 cell viability and ultrastructure (TEM), trying to identify primary and more evident alterations that can be related to neuronal damages similar to that seen in animal PD models. Cell viability decreased after 24 h rotenone treatment, with a further decrease after 48 h. Ultrastructural changes included vacuolar degeneration, mitochondrial mild swelling, decrease in the number of neuropeptide granules, and the loss of cell-to-cell adhesion. These findings are in agreement with previous research suggesting that rotenone, by inhibiting energy production and increasing ROS generation, is responsible for significant alterations of the ultrastructure and cell death of PC12 cells. Our data confirm the link between rotenone exposure, neuronal damage, and changes in dopamine metabolism, suggesting its role in the pathogenesis of PD.

Epidemiological profile of neuroendocrine tumors in adults in Brazil.

Neuroendocrine tumors (NETs) are a set of diseases that originate from neuroendocrine cells, which comprises a diffuse endocrine system present in various organs of the body. These tumors are more frequent in the gastrointestinal tract (70%) and the bronchopulmonary system (20%-30%). A NET incidence rate of 1-5 per 100,000 inhabitants has been estimated for several European countries and the USA employing 20 years of data. However, no comprehensive studies on this rare neoplasm are available in Brazil. In this context, the aim of this study was to characterize the epidemiological NET profile in the country. This is a retrospective descriptive observational study based on data from Hospital Cancer Records available at the Brazilian National Cancer Institute and the São Paulo Oncocentro Foundation. Demographic, clinical and treatmentrelated variables were analyzed from selected cases employing descriptive statistics. A total of 15,859 cases were identified, most occurring in males (53.4%) and in individuals under 65 years old (63.3%). Small cell carcinoma was the most frequent histological type (46.7%). Bronchopulmonary tumors were the most frequent NETs, followed by pancreatic tumors, with cases mostly concentrated in high complexity centers in the Brazilian Southeast and treated mainly with surgery and chemotherapy, with over half of the patients diagnosed in advanced stages of the disease.

Rare Nasopharyngeal Neuroendocrine Tumor in a 26-Year-Old Female: Case Report and Literature Review.

Neuroendocrine neoplasms (NENs) represent a collection of highly varied tumors that originate from neuroendocrine cells. They are considered rare tumors that predominantly affect the lungs. Epithelial NENs can be categorized into neuroendocrine tumors (NETs) and neuroendocrine carcinomas. It is extremely rare for NET grade 1 (NET G1) to exist in the nasopharynx, these tumors are slow-growing and the onset of symptoms and identification of the tumor may take several years. The majority of cases occur in ages between 60 and 65 years. In this article, we present a case of a 26-year-old female who presented with recurrent epistaxis and nasal obstruction for one and a half years. Magnetic resonance imaging revealed a substantial nasopharyngeal mass. Subsequently, a biopsy was conducted, and the histopathological results indicated a NET G1. Our literature review revealed 5 cases of NET G1 in the nasopharynx, with our patient being the youngest among all published cases.

Opposing effects of cannabidiol (CBD) on pheochromocytoma/paraganglioma and neuroendocrine tumor cell lines and individual patient-derived primary cultures

Opposing effects of cannabidiol (CBD) on pheochromocytoma/paraganglioma and neuroendocrine tumor cell lines and individual patient-derived primary cultures

Sensitized serotonin-mediated vasodilation in a mouse model of carcinoid disease

Background: Carcinoid tumors secrete vasoactive hormones such as serotonin that impact cardiovascular function. In consequence, patients with metastatic carcinoid disease are at risk for carcinoid syndrome, characterized by profound cutaneous flushing, hypotension, and syncope. Our recent work demonstrates that in patients with carcinoid metastases, higher serotonin levels are associated with lower vascular resistance. However, it is unknown if the vascular sensitivity to serotonin is affected by carcinoid disease. The receptor that mediates the potential vasodilatory effects of serotonin in carcinoid disease is also unknown. Therefore, we hypothesize that serotonin-mediated vasodilation is increased by carcinoid metastases. To test this, we assessed vascular reactivity to serotonin ex vivo in a mouse model of carcinoid disease. Methods: J:Nu nude mice (10 weeks) received intrasplenic injection of 2x107 BON1 neuroendocrine tumor cells (BON1, n=5) or PBS-vehicle (VEH, n=5), and were monitored for 10 weeks to allow the development of liver carcinoid metastases. Animals were then euthanized, and mesentery arteries were harvested. Isolated, pressurized mesentery arteries were pre-constricted with phenylephrine. The dose-response vasodilation to serotonin and acetylcholine was measured. These dose responses were repeated in the presence of 5-HT2B receptor antagonist LY272015 or nitric oxide synthase inhibitor L-NAME. Endothelium-independent vasodilation to sodium nitroprusside was also assessed. Data are mean ± SEM. Results: Mesentery arteries from BON1 mice had a greater vasodilation in response to serotonin compared with arteries from VEH mice (65±6% vs. 44±8%, p=0.04). Incubation with L-NAME partially inhibited the vasodilation to serotonin in the BON1 arteries (42±10%, p=0.04), but not in VEH arteries (30±11%, p=0.17). LY272015 did not affect the serotonin-induced vasodilation in the BON1 or VEH arteries (BON1: 52±10%, p=0.14, VEH: 49±17%, p=0.39). In contrast to serotonin, the vasodilation to acetylcholine did not differ between BON1 and VEH arteries (77±9% vs. 61±16%, p=0.19). There were also no differences in the vasodilation to sodium nitroprusside between groups (p=0.42). Arteries from BON1 mice had a trend for greater vasoconstriction in phenylephrine compared with VEH mice (51±7% vs. 37±9%, p=0.06). Conclusions: These findings demonstrate that serotonin-mediated vasodilation is sensitized in a mouse model of carcinoid disease. This is potentially accompanied by enhanced α-adrenergic-mediated vasoconstriction, which may be a compensatory mechanism in response to sensitized vasodilatory mechanisms. Western University of Health Sciences Intramural Grant (BHM). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Inhibition of ribonucleotide reductase subunit M2 enhances the radiosensitivity of metastatic pancreatic neuroendocrine tumor

Ribonucleotide Reductase (RNR) is a rate-limiting enzyme in the production of deoxyribonucleoside triphosphates (dNTPs), which are essential substrates for DNA repair after radiation damage. We explored the radiosensitization property of RNR and investigated a selective RRM2 inhibitor, 3-AP, as a radiosensitizer in the treatment of metastatic pNETs. We investigated the role of RNR subunit, RRM2, in pancreatic neuroendocrine (pNET) cells and responses to radiation in vitro. We also evaluated the selective RRM2 subunit inhibitor, 3-AP, as a radiosensitizer to treat pNET metastases in vivo. Knockdown of RNR subunits demonstrated that RRM1 and RRM2 subunits, but not p53R3, play significant roles in cell proliferation. RRM2 inhibition activated DDR pathways through phosphorylation of ATM and DNA-PK protein kinases but not ATR. RRM2 inhibition also induced Chk1 and Chk2 phosphorylation, resulting in G1/S phase cell cycle arrest. RRM2 inhibition sensitized pNET cells to radiotherapy and induced apoptosis in vitro. In vivo, we utilized pNET subcutaneous and lung metastasis models to examine the rationale for RNR-targeted therapy and 3-AP as a radiosensitizer in treating pNETs. Combination treatment significantly increased apoptosis of BON (human pNET) xenografts and significantly reduced the burden of lung metastases. Together, our results demonstrate that selective RRM2 inhibition induced radiosensitivity of metastatic pNETs both in vitro and in vivo. Therefore, treatment with the selective RRM2 inhibitor, 3-AP, is a promising radiosensitizer in the therapeutic armamentarium for metastatic pNETs.

Morphological Characteristics of Colon Tumors in Mice with Different Tolerance to Hypoxia.

In adult male C57BL/6 mice with high (HR) and low (LR) resistance to hypoxia, morphological features of colon tumors and blood parameters were evaluated 70 days after intraperitoneal injection of azoxymethane and subsequent consumption of 3 cycles of dextran sulfate sodium. On macroscopic analysis, tumors were found in the distal colon in 35% (7 of 20 animals) of HR and 31% (4 of 13 animals) of LR animals. Microscopic analysis of the distal colon revealed tumors in 75% (15 of 20 animals) of HR and 69% (9 of 13 animals) of LR mice. The tumors were presented by areas of glandular intraepithelial neoplasia and adenocarcinomas; the incidence and the area of the tumors did not differ in groups of HR and LR mice. The number of neuroendocrine and goblet cells in the distal colon mucosa in the areas of tumors was similar in the compared groups. However, in both HR and LR mice of the experimental groups, the content of goblet cells in tumors was lower and the content of endocrine cells was higher than in the corresponding control groups. In the peripheral blood, the erythrocyte count and hemoglobin content decreased in HR and LR mice of the experimental groups; the relative number of monocytes increased only in HR mice and the absolute number of lymphocytes and monocytes decreased in LR mice. Thus, 70 days after azoxymethane administration and dextran sulfate sodium consumption, the tumors in mice were presented by glandular intraepithelial neoplasia and adenocarcinomas, and their incidence and area did not differ between animals with different tolerance to hypoxia.