Synergistic antitumor activity by dual blockade of CCR1 and CXCR2 expressed on myeloid cells within the tumor microenvironment.

BACKGROUND: Chemokine signaling within the tumor microenvironment can promote tumor progression. Although CCR1 and CXCR2 on myeloid cells could be involved in tumor progression, it remains elusive what effect would be observed if both of those are blocked. METHODS: We employed two syngeneic colorectal cancer mouse models: a transplanted tumor model and a liver metastasis model. We generated double-knockout mice for CCR1 and CXCR2, and performed bone marrow (BM) transfer experiments in which sub-lethally irradiated wild-type mice were reconstituted with BM from either wild-type, Ccr1-/-, Cxcr2-/- or Ccr1-/-Cxcr2-/- mice. RESULTS: Myeloid cells that express MMP2, MMP9 and VEGF were accumulated around both types of tumors through CCR1- and CXCR2-mediated pathways. Mice reconstituted with Ccr1-/-Cxcr2-/- BM exhibited the strongest suppression of tumor growth and liver metastasis compared with other three groups. Depletion of CCR1+CXCR2+ myeloid cells led to a higher frequency of CD8+ T cells, whereas the numbers of Ly6G+ neutrophils, FOXP3+ Treg cells and CD31+ endothelial cells were significantly decreased. Furthermore, treatment with a neutralizing anti-CCR1 mAb to mice reconstituted with Cxcr2-/- BM significantly suppressed tumor growth and liver metastasis. CONCLUSION: Dual blockade of CCR1 and CXCR2 pathways in myeloid cells could be an effective therapy against colorectal cancer.

Epithelial aPKC deficiency leads to stem cell loss preceding metaplasia in colorectal cancer initiation.

The early mechanisms of spontaneous tumor initiation that precede malignancy are largely unknown. We show that reduced aPKC levels correlate with stem cell loss and the induction of revival and metaplastic programs in serrated- and conventional-initiated premalignant lesions, which is perpetuated in colorectal cancers (CRCs). Acute inactivation of PKCλ/ι in vivo and in mouse organoids is sufficient to stimulate JNK in non-transformed intestinal epithelial cells (IECs), which promotes cell death and the rapid loss of the intestinal stem cells (ISCs), including those that are LGR5+. This is followed by the accumulation of revival stem cells (RSCs) at the bottom of the crypt and fetal-metaplastic cells (FMCs) at the top, creating two spatiotemporally distinct cell populations that depend on JNK-induced AP-1 and YAP. These cell lineage changes are maintained during cancer initiation and progression and determine the aggressive phenotype of human CRC, irrespective of their serrated or conventional origin.

Stage at diagnosis of colorectal cancer through diagnostic route: Who should be screened?

BACKGROUND: Colorectal cancer (CRC) is a global health concern, with advanced-stage diagnoses contributing to poor prognoses. The efficacy of CRC screening has been well-established; nevertheless, a significant proportion of patients remain unscreened, with > 70% of cases diagnosed outside screening. Although identifying specific subgroups for whom CRC screening should be particularly recommended is crucial owing to limited resources, the association between the diagnostic routes and identification of these subgroups has been less appreciated. In the Japanese cancer registry, the diagnostic routes for groups discovered outside of screening are primarily categorized into those with comorbidities found during hospital visits and those with CRC-related symptoms. AIM: To clarify the stage at CRC diagnosis based on diagnostic routes. METHODS: We conducted a retrospective observational study using a cancer registry of patients with CRC between January 2016 and December 2019 at two hospitals. The diagnostic routes were primarily classified into three groups: Cancer screening, follow-up, and symptomatic. The early-stage was defined as Stages 0 or I. Multivariate and univariate logistic regressions were exploited to determine the odds of early-stage diagnosis in the symptomatic and cancer screening groups, referencing the follow-up group. The adjusted covariates were age, sex, and tumor location. RESULTS: Of the 2083 patients, 715 (34.4%), 1064 (51.1%), and 304 (14.6%) belonged to the follow-up, symptomatic, and cancer screening groups, respectively. Among the 2083 patients, CRCs diagnosed at an early stage were 57.3% (410 of 715), 23.9% (254 of 1064), and 59.5% (181 of 304) in the follow-up, symptomatic, and cancer screening groups, respectively. The symptomatic group exhibited a lower likelihood of early-stage diagnosis than the follow-up group [P < 0.001, adjusted odds ratio (aOR), 0.23; 95% confidence interval (95%CI): 0.19-0.29]. The likelihood of diagnosis at an early stage was similar between the follow-up and cancer screening groups (P = 0.493, aOR for early-stage diagnosis in the cancer screening group vs follow-up group = 1.11; 95%CI = 0.82-1.49). CONCLUSION: CRCs detected during hospital visits for comorbidities were diagnosed earlier, similar to cancer screening. CRC screening should be recommended, particularly for patients without periodical hospital visits for comorbidities.

Enhanced SREBP2-driven cholesterol biosynthesis by PKCλ/ι deficiency in intestinal epithelial cells promotes aggressive serrated tumorigenesis.

The metabolic and signaling pathways regulating aggressive mesenchymal colorectal cancer (CRC) initiation and progression through the serrated route are largely unknown. Although relatively well characterized as BRAF mutant cancers, their poor response to current targeted therapy, difficult preneoplastic detection, and challenging endoscopic resection make the identification of their metabolic requirements a priority. Here, we demonstrate that the phosphorylation of SCAP by the atypical PKC (aPKC), PKCλ/ι promotes its degradation and inhibits the processing and activation of SREBP2, the master regulator of cholesterol biosynthesis. We show that the upregulation of SREBP2 and cholesterol by reduced aPKC levels is essential for controlling metaplasia and generating the most aggressive cell subpopulation in serrated tumors in mice and humans. Since these alterations are also detected prior to neoplastic transformation, together with the sensitivity of these tumors to cholesterol metabolism inhibitors, our data indicate that targeting cholesterol biosynthesis is a potential mechanism for serrated chemoprevention.

First case of Cutibacterium avidum-infected pelvic lymphocele post-lymphadenectomy for endometrial cancer: A case report.

Background: Pelvic lymphocele (lymphocyst) infection after lymphadenectomy is a rare complication that can cause the spread of inflammation to neighboring organs whose microbiology is not well known. Cutibacterium avidum causes various infections. However, no case reports of C. avidum pelvic lymphocele infection are available; therefore, its clinical characteristics in pelvic lymphocele infections remain unknown. Case presentation: A 38-year-old woman with obesity (body mass index: 38.1 kg/m2) and a history of pelvic lymphadenectomy and chemotherapy for endometrial cancer presented with worsening left lower quadrant (LLQ) pain with fever. Physical examination revealed decreased abdominal bowel sounds and tenderness on LLQ palpation with no signs of peritonitis. Computed tomography (CT) revealed an infected left pelvic lymphocele with inflammation spreading to the adjacent sigmoid colon. Following blood culture, ampicillin/sulbactam (2 g/1 g every 6 h) was administered intravenously. Anaerobic culture bottles revealed gram-positive rods on day 4 of incubation at 37 °C. No other disseminated foci were observed in enhanced whole-body CT and upon transthoracic echocardiography. The isolates grew aerobically and anaerobically on blood agar plates with strong hemolysis. The bacterium was identified as C. avidum using a combination of characteristic peak analysis with matrix-assisted laser desorption ionization (MALDI) and 16S rRNA gene sequencing. The patient was diagnosed with C. avidum pelvic lymphocele infection. Based on penicillin susceptibility, the patient was successfully treated with intravenous ampicillin/sulbactam and de-escalated with intravenous ampicillin (2 g every 6 h) for 10 days, followed by oral amoxicillin (2000 mg/day) for an additional 11 days without drainage. Conclusions: C. avidum should be considered a causative microorganism of pelvic lymphocele infection. Peak analysis using MALDI and distinctive growth on blood agar plates are suitable for identifying C. avidum. Mild pelvic lymphocele caused by C. avidum can be treated with a short course of appropriate antimicrobial treatment without surgical intervention.

Group A Streptococcus dysgalactiae subspecies equisimilis vertebral osteomyelitis accompanied by progressive atlantoaxial subluxation: A case report and literature review.

RATIONALE: Clinically, vertebral osteomyelitis commonly occurs in immunocompromised individuals, such as people with diabetes, immunosuppression, chronic liver disease, and malignancy. Microbiologically, vertebral osteomyelitis is commonly caused by Staphylococcus aureus; however, Streptococcus dysgalactiae subspecies equisimilis (SDSE) may also potentially cause vertebral osteomyelitis, albeit rarely. Since no case reports have documented the occurrence of SDSE cervical osteomyelitis accompanied by progressive atlantoaxial subluxation, its clinical characteristics remain uncertain. Herein, we report the first case of progressive atlantoaxial subluxation in addition to cervical osteomyelitis due to septic atlantoaxial arthritis caused by SDSE in an immunocompetent individual, and provide a review of the relevant literature. PATIENT CONCERNS: A 63-year-old man with hypertension but no history of trauma or musculoskeletal disorders presented with worsening neck pain for 1 month without fever. Physical examination revealed neck pain due to neck retroflexion and tenderness with swelling of the upper cervical spine. No neurological deficit was observed. Magnetic resonance imaging revealed low-intensity areas on a T1-weighted image and high-intensity areas on a short tau inversion recovery image at the C2, C5, and C6 vertebral bodies with atlantoaxial subluxation. Two sets of blood culture tests (aerobic and anaerobic) were performed. DIAGNOSES: The anaerobic blood culture bottle showed the presence of beta-hemolytic pyrrolidonyl arylamidase-negative SDSE expressing Lancefield group A antiserum. Hence, the patient was diagnosed with SDSE cervical osteomyelitis with atlantoaxial subluxation; intensive intravenous ampicillin (2 g every 6 hours) - which is effective against SDSE - was administered. INTERVENTIONS: Posterior fusion (occipital bone, C4) was performed on day 33 because a follow-up magnetic resonance imaging on day 31 revealed progression of atlantoaxial subluxation with thickened atlantodental soft tissue. OUTCOMES: The patient's neck pain was completely relieved after treatment with intravenous ampicillin for 6 weeks, followed by oral amoxicillin (1500 mg) daily for an additional 4 weeks. The patient did not experience recurrence or sequelae during the 2-year follow-up period. LESSONS: SDSE expressing Lancefield group A antiserum can cause afebrile vertebral osteomyelitis and progressive atlantoaxial subluxation due to the occurrence of septic atlantoaxial arthritis in immunocompetent individuals. Spinal instrumentation for vertebral osteomyelitis may be acceptable after 6 weeks of antimicrobial therapy.

Pancreatic RECK inactivation promotes cancer formation, epithelial-mesenchymal transition, and metastasis.

RECK is downregulated in various human cancers; however, how RECK inactivation affects carcinogenesis remains unclear. We addressed this issue in a pancreatic ductal adenocarcinoma (PDAC) mouse model and found that pancreatic Reck deletion dramatically augmented the spontaneous development of PDAC with a mesenchymal phenotype, which was accompanied by increased liver metastases and decreased survival. Lineage tracing revealed that pancreatic Reck deletion induced epithelial-mesenchymal transition (EMT) in PDAC cells, giving rise to inflammatory cancer-associated fibroblast-like cells in mice. Splenic transplantation of Reck-null PDAC cells resulted in numerous liver metastases with a mesenchymal phenotype, whereas reexpression of RECK markedly reduced metastases and changed the PDAC tumor phenotype into an epithelial one. Consistently, low RECK expression correlated with low E-cadherin expression, poor differentiation, metastasis, and poor prognosis in human PDAC. RECK reexpression in the PDAC cells was found to downregulate MMP2 and MMP3, with a concomitant increase in E-cadherin and decrease in EMT-promoting transcription factors. An MMP inhibitor recapitulated the effects of RECK on the expression of E-cadherin and EMT-promoting transcription factors and invasive activity. These results establish the authenticity of RECK as a pancreatic tumor suppressor, provide insights into its underlying mechanisms, and support the idea that RECK could be an important therapeutic effector against human PDAC.

THBS1-producing tumor-infiltrating monocyte-like cells contribute to immunosuppression and metastasis in colorectal cancer.

Mesenchymal activation, characterized by dense stromal infiltration of immune and mesenchymal cells, fuels the aggressiveness of colorectal cancers (CRC), driving progression and metastasis. Targetable molecules in the tumor microenvironment (TME) need to be identified to improve the outcome in CRC patients with this aggressive phenotype. This study reports a positive link between high thrombospondin-1 (THBS1) expression and mesenchymal characteristics, immunosuppression, and unfavorable CRC prognosis. Bone marrow-derived monocyte-like cells recruited by CXCL12 are the primary source of THBS1, which contributes to the development of metastasis by inducing cytotoxic T-cell exhaustion and impairing vascularization. Furthermore, in orthotopically generated CRC models in male mice, THBS1 loss in the TME renders tumors partially sensitive to immune checkpoint inhibitors and anti-cancer drugs. Our study establishes THBS1 as a potential biomarker for identifying mesenchymal CRC and as a critical suppressor of antitumor immunity that contributes to the progression of this malignancy with a poor prognosis.

Simultaneous activation of Kras-Akt and Notch pathways induces extrahepatic biliary cancer via the mTORC1 pathway.

Biliary tract cancer (BTC) has poor prognosis. The Notch receptor is aberrantly expressed in extrahepatic cholangiocarcinoma (eCCA). However, the role of Notch signaling in the initiation and progression of eCCA and gallbladder (GB) cancer remains unknown. Therefore, we investigated the functional role of Notch signaling during tumorigenesis of the extrahepatic bile duct (EHBD) and GB. Activation of Notch signaling and oncogenic Kras resulted in the development of biliary intraepithelial neoplasia (BilINs) in the EHBD and GB, which were premalignant lesions that progressed to adenocarcinoma in mice. The expression of genes involved in the mTORC1 pathway was increased in biliary spheroids from Hnf1b-CreERT2; KrasLSL-G12D ; Rosa26LSL-NotchIC mice and inhibition of the mTORC1 pathway suppressed spheroid growth. Additionally, simultaneous activation of the PI3K-AKT and Notch pathways in EHBD and GB induced biliary cancer development in mice. Consistent with this, we observed a significant correlation between activated NOTCH1 and phosphorylated Ribosomal Protein S6 (p-S6) expression in human eCCA. Furthermore, inhibition of the mTORC1 pathway suppressed the growth of Notch-activated human biliary cancer cells in vitro and in vivo. Mechanistically, the Kras/Notch-Myc axis activated mTORC1 through TSC2 phosphorylation in mutant biliary spheroids. These data indicate that inhibition of the mTORC1 pathway could be an effective treatment strategy for Notch-activated human eCCA. © 2023 The Pathological Society of Great Britain and Ireland.

Pancreatic metastasis from lung adenocarcinoma.

TTF-1 is a highly useful marker to assist in differentiating between pulmonary and nonpulmonary, nonthyroid adenocarcinomas. Our case shows that TTF-1 is highly useful in differentiating between pancreatic metastasis from lung adenocarcinoma and primary pancreatic cancer, especially when the clinical course and imaging findings are not helpful for differentiating them.

Sessile serrated lesions with dysplasia: is it possible to nip them in the bud?

The serrated neoplasia pathway constitutes an "alternative route" to colorectal cancer (CRC), and sessile serrated lesions with dysplasia (SSLDs) are an intermediate step between sessile serrated lesions (SSLs) and invasive CRC in this pathway. While SSLs show indolent growth before becoming dysplastic (> 10-15 years), SSLDs are considered to rapidly progress to either immunogenic microsatellite instable-high (MSI-H) CRC (presumably 75% of cases) or mesenchymal microsatellite stable (MSS) CRC. Their flat shapes and the relatively short window of this intermediate state make it difficult to detect and diagnose SSLDs; thus, these lesions are potent precursors of post-colonoscopy/interval cancers. Confusing terminology and the lack of longitudinal observation data of serrated polyps have hampered the accumulation of knowledge about SSLDs; however, a growing body of evidence has started to clarify their characteristics and biology. Together with recent efforts to incorporate terminology, histological studies of SSLDs have identified distinct dysplastic patterns and revealed alterations in the tumor microenvironment (TME). Molecular studies at the single-cell level have identified distinct gene alterations in both the epithelium and the TME. Mouse serrated tumor models have demonstrated the importance of TME in disease progression. Advances in colonoscopy provide clues to distinguish pre-malignant from non-malignant-SSLs. Recent progress in all aspects of the field has enhanced our understanding of the biology of SSLDs. The aim of this review article was to assess the current knowledge of SSLDs and highlight their clinical implications.

An exploratory study for tuft cells in the breast and their relevance in triple-negative breast cancer: the possible relationship of SOX9.

BACKGROUND: Breast cancer is highly heterogeneous, suggesting that small but relevant subsets have been under-recognized. Rare and mainly triple-negative breast cancers (TNBCs) were recently found to exhibit tuft cell-like expression profiles, including POU2F3, the tuft cell master regulator. In addition, immunohistochemistry (IHC) has identified POU2F3-positive cells in the normal human breast, suggesting the presence of tuft cells in this organ. METHODS: Here, we (i) reviewed previously identified POU2F3-positive invasive breast cancers (n = 4) for POU2F3 expression in intraductal cancer components, (ii) investigated a new cohort of invasive breast cancers (n = 1853) by POU2F3-IHC, (iii) explored POU2F3-expressing cells in non-neoplastic breast tissues obtained from women with or without BRCA1 mutations (n = 15), and (iv) reanalyzed publicly available single-cell RNA sequencing (scRNA-seq) data from normal breast cells. RESULTS: Two TNBCs of the four previously reported invasive POU2F3-positive breast cancers contained POU2F3-positive ductal carcinoma in situ (DCIS). In the new cohort of invasive breast cancers, IHC revealed four POU2F3-positive cases, two of which were triple-negative, one luminal-type, and one triple-positive. In addition, another new POU2F3-positive tumor with a triple-negative phenotype was found in daily practice. All non-neoplastic breast tissues contained POU2F3-positive cells, irrespective of BRCA1 status. The scRNA-seq reanalysis confirmed POU2F3-expressing epithelial cells (3.3% of all epithelial cells) and the 17% that co-expressed the other two tuft cell-related markers (SOX9/AVIL or SOX9/GFI1B), which suggested they were bona fide tuft cells. Of note, SOX9 is also known as the "master regulator" of TNBCs. CONCLUSIONS: POU2F3 expression defines small subsets in various breast cancer subtypes, which can be accompanied by DCIS. The mechanistic relationship between POU2F3 and SOX9 in the breast warrants further analysis to enhance our understanding of normal breast physiology and to clarify the significance of the tuft cell-like phenotype for TNBCs.

Brg1 controls stemness and metastasis of pancreatic cancer through regulating hypoxia pathway.

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease. We previously reported that chromatin remodeler Brg1 is essential for acinar cell-derived PDAC formation in mice. However, the functional role of Brg1 in established PDAC and its metastasis remains unknown. Here, we investigated the importance of Brg1 for established PDAC by using a mouse model with a dual recombinase system. We discovered that Brg1 was a critical player for the cell survival and growth of spontaneously developed PDAC in mice. In addition, Brg1 was essential for metastasis of PDAC cells by inhibiting apoptosis in splenic injection and peritoneal dissemination models. Moreover, cancer stem-like property was compromised in PDAC cells by Brg1 ablation. Mechanistically, the hypoxia pathway was downregulated in Brg1-deleted mouse PDAC and BRG1-low human PDAC. Brg1 was essential for HIF-1α to bind to its target genes to augment the hypoxia pathway, which was important for PDAC cells to maintain their stem-like properties and to metastasize to the liver. Human PDAC cells with high BRG1 expression were more susceptible to BRG1 suppression. In conclusion, Brg1 plays a critical role for cell survival, stem-like property and metastasis of PDAC through the regulation of hypoxia pathway, and thus could be a novel therapeutic target for PDAC.

p53 protects against formation of extrahepatic biliary precancerous lesions in the context of oncogenic Kras.

KRAS and TP53 mutations are frequently observed in extrahepatic biliary cancer. Mutations of KRAS and TP53 are independent risk factors for poor prognosis in biliary cancer. However, the exact role of p53 in the development of extrahepatic biliary cancer remains elusive. In this study, we found that simultaneous activation of Kras and inactivation of p53 induces biliary neoplasms that resemble human biliary intraepithelial neoplasia in the extrahepatic bile duct and intracholecystic papillary-tubular neoplasm in the gall bladder in mice. However, inactivation of p53 was not sufficient for the progression of biliary precancerous lesions into invasive cancer in the context of oncogenic Kras within the observation period. This was also the case in the context of additional activation of the Wnt signaling pathway. Thus, p53 protects against formation of extrahepatic biliary precancerous lesions in the context of oncogenic Kras.

On the origin of gastric tumours: analysis of a case with intramucosal gastric carcinoma and oxyntic gland adenoma.

Most gastric cancers develop in inflamed gastric mucosa due to Helicobacter pylori infection, typically with metaplastic changes. However, the origins of gastric cancer remain unknown. Here, we present a case of intramucosal gastric carcinoma (IGC) and oxyntic gland adenoma (OGA) derived from spasmolytic polypeptide-expressing metaplasia (SPEM). Early gastric cancer adjacent to a polyp was found in the upper corpus of a 71-year-old woman without H. pylori infection and was endoscopically resected. Histological examination showed IGC and OGA, both of which had predominant MUC6 expression. Interestingly, gastric glands with enriched MUC6-positive mucous cells, referred to as SPEM, expanded between them. Whole-exome sequencing analysis revealed a truncating KRAS(G12D) mutation in IGC, OGA, and SPEM. In addition, TP53 and CDKN2A mutations and a loss of chromosome 17p were found in the IGC, whereas a GNAS mutation was observed in the OGA. These results indicated that IGC and OGA originated from the KRAS-mutated SPEM. © 2023 The Pathological Society of Great Britain and Ireland.

Differential involvement of LUBAC-mediated linear ubiquitination in intestinal epithelial cells and macrophages during intestinal inflammation.

Disruption of the intestinal epithelial barrier and dysregulation of macrophages are major factors contributing to the pathogenesis of inflammatory bowel diseases (IBDs). Activation of NF-κB and cell death are involved in maintaining intestinal homeostasis in a cell type-dependent manner. Although both are regulated by linear ubiquitin chain assembly complex (LUBAC)-mediated linear ubiquitination, the physiological relevance of linear ubiquitination to intestinal inflammation remains unexplored. Here, we used two experimental mouse models of IBD (intraperitoneal LPS and oral dextran sodium sulfate [DSS] administration) to examine the role of linear ubiquitination in intestinal epithelial cells (IECs) and macrophages during intestinal inflammation. We did this by deleting the linear ubiquitination activity of LUBAC specifically from IECs or macrophages. Upon LPS administration, loss of ligase activity in IECs induced mucosal inflammation and augmented IEC death. LPS-mediated death of LUBAC-defective IECs was triggered by TNF. IEC death was rescued by an anti-TNF antibody, and TNF (but not LPS) induced apoptosis of organoids derived from LUBAC-defective IECs. However, augmented TNF-mediated IEC death did not overtly affect the severity of colitis after DSS administration. By contrast, defective LUBAC ligase activity in macrophages ameliorated DSS-induced colitis by attenuating both infiltration of macrophages and expression of inflammatory cytokines. Decreased production of macrophage chemoattractant MCP-1/CCL2, as well as pro-inflammatory IL-6 and TNF, occurred through impaired activation of NF-κB and ERK via loss of ligase activity in macrophages. Taken together, these results indicate that both intraperitoneal LPS and oral DSS administrations are beneficial for evaluating epithelial integrity under inflammatory conditions, as well as macrophage functions in the event of an epithelial barrier breach. The data clarify the cell-specific roles of linear ubiquitination as a critical regulator of TNF-mediated epithelial integrity and macrophage pro-inflammatory responses during intestinal inflammation. © 2022 The Pathological Society of Great Britain and Ireland.

A case of neuroendocrine neoplasm of the minor duodenal papilla.

A 61-year-old woman was referred to our hospital for intraductal papillary mucinous neoplasm with no symptoms. Magnetic resonance imaging (MRI) depicted a 15 mm nodular lesion at the descending portion of duodenum. Upper gastrointestinal endoscopy showed a submucosal tumor-like mass at the minor duodenal papilla. A boring biopsy of the tumor revealed a neuroendocrine neoplasm (NEN). Various blood hormone tests were all within normal limits, and the tumor was considered to be nonfunctional. Contrast-enhanced computed tomography showed no obvious distant metastasis, and subtotal stomach-preserving pancreaticoduodenectomy (SSPPD) was performed. Histopathological examination revealed a dense cluster of spindle-shaped cells forming a sheet-like foci and areas showing glandular lumen formation, and immunohistochemistry showed synaptophysin ( + ), chromogranin ( + ). Mitotic rate was about 11 mitoses per 2 square millimeters, Ki-67 index was about 0.2%. She was pathologically diagnosed with NEN G2 at the minor duodenal papilla with regional lymph node metastasis according to the WHO2010 classification. The patient has been currently under outpatient observation with a good postoperative course. Review of the literature identified 43 cases of NENs of the minor duodenal papilla. NENs of the minor duodenal papilla have a high rate of lymph node metastasis, even if the tumor size is small.

Hyaluronan driven by epithelial aPKC deficiency remodels the microenvironment and creates a vulnerability in mesenchymal colorectal cancer.

Mesenchymal colorectal cancer (mCRC) is microsatellite stable (MSS), highly desmoplastic, with CD8+ T cells excluded to the stromal periphery, resistant to immunotherapy, and driven by low levels of the atypical protein kinase Cs (aPKCs) in the intestinal epithelium. We show here that a salient feature of these tumors is the accumulation of hyaluronan (HA) which, along with reduced aPKC levels, predicts poor survival. HA promotes epithelial heterogeneity and the emergence of a tumor fetal metaplastic cell (TFMC) population endowed with invasive cancer features through a network of interactions with activated fibroblasts. TFMCs are sensitive to HA deposition, and their metaplastic markers have prognostic value. We demonstrate that in vivo HA degradation with a clinical dose of hyaluronidase impairs mCRC tumorigenesis and liver metastasis and enables immune checkpoint blockade therapy by promoting the recruitment of B and CD8+ T cells, including a proportion with resident memory features, and by blocking immunosuppression.

Thymic Carcinoma: Unraveling Neuroendocrine Differentiation and Epithelial Cell Identity Loss.

BACKGROUND: The histogenesis of thymic epithelial tumors (TETs) has been a subject of debate. Recent technological advancements have revealed that thymic carcinomas often exhibit a phenotype akin to tuft cells, which is a subset of medullary TECs. Here, we further explored the gene expression signatures of thymic carcinomas in relation to tuft cells and their kinships-ionocytes and neuroendocrine cells (neuroendocrine group). METHODS: We analyzed a single-cell RNA sequencing dataset from the normal human thymus. Concurrently, we examined publicly available datasets on the mRNA expression and methylation status of TECs and lung cancers. Real-time quantitative PCR was also conducted with our tissue samples. RESULTS: Thymic carcinomas displayed a neuroendocrine phenotype biased toward tuft cells and ionocytes. When exploring the possible regulators of this phenotype, we discovered that HDAC9 and NFATC1 were characteristically expressed in the neuroendocrine group in adult TECs and thymic carcinomas. Additionally, the pan-thymic epithelium markers, exemplified by PAX9 and SIX1, were significantly suppressed in thymic carcinomas. CONCLUSIONS: Thymic carcinomas might be characterized by unique neuroendocrine differentiation and loss of identity as thymic epithelial cells. Future studies investigating the role of HDAC9 and NFATC1 in thymic epithelium are warranted to explore their potential as therapeutic targets in TETs.