Tumor suppressive role of the epigenetic master regulator BRD3 in colorectal cancer.

Bromodomain and extraterminal domain (BET) family proteins are epigenetic master regulators of gene expression via recognition of acetylated histones and recruitment of transcription factors and co-activators to chromatin. Hence, BET family proteins have emerged as promising therapeutic targets in cancer. In this study, we examined the functional role of bromodomain containing 3 (BRD3), a BET family protein, in colorectal cancer (CRC). In vitro and vivo analyses using BRD3-knockdown or BRD3-overexpressing CRC cells showed that BRD3 suppressed tumor growth and cell cycle G1/S transition and induced p21 expression. Clinical analysis of CRC datasets from our hospital or The Cancer Genome Atlas revealed that BET family genes, including BRD3, were overexpressed in tumor tissues. In immunohistochemical analyses, BRD3 was observed mainly in the nucleus of CRC cells. According to single-cell RNA sequencing in untreated CRC tissues, BRD3 was highly expressed in malignant epithelial cells, and cell cycle checkpoint-related pathways were enriched in the epithelial cells with high BRD3 expression. Spatial transcriptomic and single-cell RNA sequencing analyses of CRC tissues showed that BRD3 expression was positively associated with high p21 expression. Furthermore, overexpression of BRD3 combined with knockdown of, a driver gene in the BRD family, showed strong inhibition of CRC cells in vitro. In conclusion, we demonstrated a novel tumor suppressive role of BRD3 that inhibits tumor growth by cell cycle inhibition in part via induction of p21 expression. BRD3 activation might be a novel therapeutic approach for CRC.

Subclonal accumulation of immune escape mechanisms in microsatellite instability-high colorectal cancers.

BACKGROUND: Intratumor heterogeneity (ITH) in microsatellite instability-high (MSI-H) colorectal cancer (CRC) has been poorly studied. We aimed to clarify how the ITH of MSI-H CRCs is generated in cancer evolution and how immune selective pressure affects ITH. METHODS: We reanalyzed public whole-exome sequencing data on 246 MSI-H CRCs. In addition, we performed a multi-region analysis from 6 MSI-H CRCs. To verify the process of subclonal immune escape accumulation, a novel computational model of cancer evolution under immune pressure was developed. RESULTS: Our analysis presented the enrichment of functional genomic alterations in antigen-presentation machinery (APM). Associative analysis of neoantigens indicated the generation of immune escape mechanisms via HLA alterations. Multiregion analysis revealed the clonal acquisition of driver mutations and subclonal accumulation of APM defects in MSI-H CRCs. Examination of variant allele frequencies demonstrated that subclonal mutations tend to be subjected to selective sweep. Computational simulations of tumour progression with the interaction of immune cells successfully verified the subclonal accumulation of immune escape mutations and suggested the efficacy of early initiation of an immune checkpoint inhibitor (ICI) -based treatment. CONCLUSIONS: Our results demonstrate the heterogeneous acquisition of immune escape mechanisms in MSI-H CRCs by Darwinian selection, providing novel insights into ICI-based treatment strategies.

Convergent genomic diversity and novel BCAA metabolism in intrahepatic cholangiocarcinoma.

BACKGROUND: Driver alterations may represent novel candidates for driver gene-guided therapy; however, intrahepatic cholangiocarcinoma (ICC) with multiple genomic aberrations makes them intractable. Therefore, the pathogenesis and metabolic changes of ICC need to be understood to develop new treatment strategies. We aimed to unravel the evolution of ICC and identify ICC-specific metabolic characteristics to investigate the metabolic pathway associated with ICC development using multiregional sampling to encompass the intra- and inter-tumoral heterogeneity. METHODS: We performed the genomic, transcriptomic, proteomic and metabolomic analysis of 39-77 ICC tumour samples and eleven normal samples. Further, we analysed their cell proliferation and viability. RESULTS: We demonstrated that intra-tumoral heterogeneity of ICCs with distinct driver genes per case exhibited neutral evolution, regardless of their tumour stage. Upregulation of BCAT1 and BCAT2 indicated the involvement of 'Val Leu Ile degradation pathway'. ICCs exhibit the accumulation of ubiquitous metabolites, such as branched-chain amino acids including valine, leucine, and isoleucine, to negatively affect cancer prognosis. We revealed that this metabolic pathway was almost ubiquitously altered in all cases with genomic diversity and might play important roles in tumour progression and overall survival. CONCLUSIONS: We propose a novel ICC onco-metabolic pathway that could enable the development of new therapeutic interventions.

Transducin Beta-Like 2 is a Potential Driver Gene that Adapts to Endoplasmic Reticulum Stress to Promote Tumor Growth of Lung Adenocarcinoma.

BACKGROUND: Endoplasmic reticulum (ER) stress has a close relation with cancer progression. Blocking the adaptive pathway of ER stress could be an anticancer strategy. Here, we identified an ER stress-related gene, Transducin beta-like 2 (TBL2), an ER-localized type I transmembrane protein, on increased chromosome 7q as a candidate driver gene of lung adenocarcinoma (LUAD). METHODS: The association between TBL2 mRNA expression and prognostic outcomes and clinicopathological factors was analyzed using The Cancer Genome Atlas (TCGA) datasets of LUAD and lung squamous cell carcinoma (LUSC). Localization of TBL2 in tumor tissues was observed by immunohistochemical staining. Gene set enrichment analysis (GSEA) was conducted using TCGA dataset. In vitro cell proliferation assays were performed using TBL2 knockdown LUAD cells, LUSC cells, and LUAD cells overexpressing TBL2. Apoptosis and ATF4 expression (ER stress marker) were evaluated by western blotting. RESULTS: TBL2 was overexpressed in LUAD and LUSC cells. Multivariate analysis indicated high TBL2 mRNA expression was an independent poor prognostic factor of LUAD. GSEA revealed high TBL2 expression was positively correlated to the ER stress response in LUAD. TBL2 knockdown attenuated LUAD cell proliferation under ER stress. TBL2 inhibited apoptosis in LUAD cells under ER stress. TBL2 knockdown reduced ATF4 expression under ER stress. CONCLUSIONS: TBL2 may be a novel driver gene that facilitates cell proliferation, possibly by upregulating ATF4 expression followed by adaptation to ER stress, and it is a poor prognostic biomarker of LUAD.

GET4 is a novel driver gene in colorectal cancer that regulates the localization of BAG6, a nucleocytoplasmic shuttling protein.

Colorectal cancer (CRC) is one of the most common types of cancer and a significant cause of cancer mortality worldwide. Further improvements of CRC therapeutic approaches are needed. BCL2-associated athanogene 6 (BAG6), a multifunctional scaffold protein, plays an important role in tumor progression. However, regulation of BAG6 in malignancies remains unclear. This study showed that guided entry of tail-anchored proteins factor 4 (GET4), a component of the BAG6 complex, regulates the intercellular localization of BAG6 in CRC. Furthermore, GET4 was identified as a candidate driver gene on the short arm of chromosome 7, which is often amplified in CRC, by our bioinformatics approach using the CRC dataset from The Cancer Genome Atlas. Clinicopathologic and prognostic analyses using CRC datasets showed that GET4 was overexpressed in tumor cells due to an increased DNA copy number. High GET4 expression was an independent poor prognostic factor in CRC, whereas BAG6 was mainly overexpressed in the cytoplasm of tumor cells without gene alteration. The biological significance of GET4 was examined using GET4 KO CRC cells generated with CRISPR-Cas9 technology or transfected CRC cells. In vitro and in vivo analyses showed that GET4 promoted tumor growth. It appears to facilitate cell cycle progression by cytoplasmic enrichment of BAG6-mediated p53 acetylation followed by reduced p21 expression. In conclusion, we showed that GET4 is a novel driver gene and a prognostic biomarker that promotes CRC progression by inducing the cytoplasmic transport of BAG6. GET4 could be a promising therapeutic molecular target in CRC.

Fanconi Anemia Complementation Group E, a DNA Repair-Related Gene, Is a Potential Marker of Poor Prognosis in Hepatocellular Carcinoma.

INTRODUCTION: Fanconi anemia complementation group E (FANCE) is a Fanconi anemia (FA) pathway gene that regulates DNA repair. We evaluated the clinical relevance of FANCE expression in hepatocellular carcinoma (HCC). METHODS: First, the associations between the expression of FA pathway genes including FANCE and clinical outcomes in HCC patients were analyzed in 2 independent cohorts: The Cancer Genome Atlas (TCGA, n = 373) and our patient cohort (n = 53). Localization of FANCE expression in HCC tissues was observed by immunohistochemical staining. Gene set enrichment analysis (GSEA) and gene network analysis (SiGN_BN) were conducted using the TCGA dataset. Next, an in vitro proliferation assay was performed using FANCE-knockdown HCC cell lines (HuH7 and HepG2). The association between mRNA expression of FANCE and that of DNA damage response genes in HCC was analyzed using TCGA and Cancer Cell Line Encyclopedia datasets. Finally, the association between FANCE mRNA expression and overall survival (OS) in various digestive carcinomas was analyzed using TCGA data. RESULTS: FANCE was highly expressed in HCC cells. Multivariate analysis indicated that high FANCE mRNA expression was an independent factor predicting poor OS. GSEA revealed a positive relationship between enhanced FANCE expression and E2F and MYC target gene expression in HCC tissues. FANCE knockdown attenuated the proliferation of HCC cells, as well as reduced cdc25A expression and elevated histone H3 pSer10 expression. SiGN_BN revealed that FANCE mRNA expression was positively correlated with DNA damage response genes (H2A histone family member X and checkpoint kinase 1) in HCC tissues. Significant effects of high FANCE expression on OS were observed in hepatobiliary pancreatic carcinomas, including HCC. CONCLUSIONS: FANCE may provide a potential therapeutic target and biomarker of poor prognosis in HCC, possibly by facilitating tumor proliferation, which is mediated partly by cell cycle signaling activation.

Mitotic checkpoint regulator RAE1 promotes tumor growth in colorectal cancer.

Microtubules are among the most successful targets for anticancer therapy because they play important roles in cell proliferation as they constitute the mitotic spindle, which is critical for chromosome segregation during mitosis. Hence, identifying new therapeutic targets encoding proteins that regulate microtubule assembly and function specifically in cancer cells is critical. In the present study, we identified a candidate gene that promotes tumor progression, ribonucleic acid export 1 (RAE1), a mitotic checkpoint regulator, on chromosome 20q through a bioinformatics approach using datasets of colorectal cancer (CRC), including The Cancer Genome Atlas (TCGA). RAE1 was ubiquitously amplified and overexpressed in tumor cells. High expression of RAE1 in tumor tissues was positively associated with distant metastasis and was an independent poor prognostic factor in CRC. In vitro and in vivo analysis showed that RAE1 promoted tumor growth, inhibited apoptosis, and promoted cell cycle progression, possibly with a decreased proportion of multipolar spindle cells in CRC. Furthermore, RAE1 induced chemoresistance through its anti-apoptotic effect. In addition, overexpression of RAE1 and significant effects on survival were observed in various types of cancer, including CRC. In conclusion, we identified RAE1 as a novel gene that facilitates tumor growth in part by inhibiting apoptosis and promoting cell cycle progression through stabilizing spindle bipolarity and facilitating tumor growth. We suggest that it is a potential therapeutic target to overcome therapeutic resistance of CRC.

The novel driver gene ASAP2 is a potential druggable target in pancreatic cancer.

Targeting mutated oncogenes is an effective approach for treating cancer. The 4 main driver genes of pancreatic ductal adenocarcinoma (PDAC) are KRAS, TP53, CDKN2A, and SMAD4, collectively called the "big 4" of PDAC, however they remain challenging therapeutic targets. In this study, ArfGAP with SH3 domain, ankyrin repeat and PH domain 2 (ASAP2), one of the ArfGAP family, was identified as a novel driver gene in PDAC. Clinical analysis with PDAC datasets showed that ASAP2 was overexpressed in PDAC cells based on increased DNA copy numbers, and high ASAP2 expression contributed to a poor prognosis in PDAC. The biological roles of ASAP2 were investigated using ASAP2-knockout PDAC cells generated with CRISPR-Cas9 technology or transfected PDAC cells. In vitro and in vivo analyses showed that ASAP2 promoted tumor growth by facilitating cell cycle progression through phosphorylation of epidermal growth factor receptor (EGFR). A repositioned drug targeting the ASAP2 pathway was identified using a bioinformatics approach. The gene perturbation correlation method showed that niclosamide, an antiparasitic drug, suppressed PDAC growth by inhibition of ASAP2 expression. These data show that ASAP2 is a novel druggable driver gene that activates the EGFR signaling pathway. Furthermore, niclosamide was identified as a repositioned therapeutic agent for PDAC possibly targeting ASAP2.

GTF2IRD1 on chromosome 7 is a novel oncogene regulating the tumor-suppressor gene TGFßR2 in colorectal cancer.

Chromosome 7q (Ch.7q) is clonally amplified in colorectal cancer (CRC). We aimed to identify oncogenes on Ch.7q that are overexpressed through DNA copy number amplification and determine the biological and clinical significance of these oncogenes in CRC. We identified general transcription factor 2I repeat domain-containing protein 1 (GTF2IRD1) as a potential oncogene using a CRC dataset from The Cancer Genome Atlas with a bioinformatics approach. We measured the expression of GTF2IRD1 in 98 patients with CRC using immunohistochemistry and RT-quantitative PCR (RT-qPCR). The biological effects of GTF2IRD1 expression were explored by gene set enrichment analysis (GSEA). Next, we undertook in vitro cell proliferation and cell cycle assays using siGTF2IRD1-transfected CRC cells. We further investigated the oncogenic mechanisms through which GTF2IRD1 promoted CRC progression. Finally, we assessed the clinical significance of GTF2IRD1 expression by RT-qPCR. GTF2IRD1 was overexpressed in tumor cells and liver metastatic lesions. The GSEA revealed a positive correlation between GTF2IRD1 expression and cell cycle progression-related genes. GTF2IRD1 knockdown inhibited cell proliferation and induced cell cycle arrest in Smad4-mutated CRC. GTF2IRD1 downregulated the expression of the gene encoding transforming growth factor ß receptor 2 (TGFßR2), a tumor-suppressor gene in Smad4-mutated CRC. On multivariate analysis, high GTF2IRD1 expression was an independent poor prognostic factor. Clinicopathological analysis showed that GTF2IRD1 expression was positively correlated with liver metastasis. In conclusion, GTF2IRD1 promoted CRC progression by downregulating TGFßR2 and could be a prognostic biomarker on Ch.7q in CRC. GTF2IRD1 could also be a novel oncogene in CRC.

Circulating PD-1 mRNA in Peripheral Blood is a Potential Biomarker for Predicting Survival of Breast Cancer Patients.

BACKGROUND: Programmed cell death 1 (PD-1) inhibitors have shown significant therapeutic promise in various cancers. However, the clinical significance of PD-1 expression remains not fully understood. In this study, we evaluated the clinical and prognostic relevance of PD-1 expression in breast cancer (BC). METHODS: First, we analyzed PD-1 mRNA expression in BC tissues and performed a survival analysis using a dataset from The Cancer Genome Atlas. Next, we measured PD-1 mRNA expression in peripheral blood (PB) in BC patients by quantitative reverse-transcription polymerase chain reaction. We performed a survival analysis and evaluated the association between PD-1 mRNA expression in PB and the clinicopathological features of 372 BC patients who underwent curative resection. Flow cytometry (FCM) analysis was performed to identify PD-1-expressing cells in PB. Finally, we determined whether there was a correlation of PD-1 mRNA expression in PB and tumor tissue. RESULTS: PD-1 mRNA expression was significantly higher in tumor tissues compared with normal tissues. Decreased PD-1 mRNA expression in tumor tissue was associated with poor overall survival (OS). PD-1 mRNA expression in PB of BC patients was higher than that of healthy volunteers, and increased PD-1 mRNA expression in PB was associated with poor OS. FCM revealed that PD-1 was mostly expressed on T cells in PB, predominantly in CD4+ T cells. PD-1 mRNA expression in PB was negatively correlated with PD-1 mRNA expression in tumor tissue. CONCLUSION: High expression of PD-1 mRNA in preoperative PB could serve as an effective biomarker that indicates poor prognosis in BC.

Prognostic Significance of PD-1, PD-L1 and CD8 Gene Expression Levels in Gastric Cancer.

INTRODUCTION: Anti-programmed cell death 1 (PD-1) therapies have shown promising clinical activity against gastric cancer (GC). We evaluated the clinical significance of immune-related gene expression in GC tissues to better understand the tumor immune microenvironment. METHODS: PD-1, PD-1 ligand 1 (PD-L1) and CD8 mRNA levels and clinicopathological factors, including survival, were examined by quantitative RT-PCR in 155 GC patients who underwent surgery. PD-1 and PD-L1 expression in tumor tissue from 24 GC patients was investigated by immunohistochemical analysis. RESULTS: PD-1, PD-L1 and CD8 mRNA levels were significantly lower in tumor tissue than in normal tissue (p < 0.0001, p < 0.05, and p < 0.0001). GC patients with low PD-1, PD-L1 and CD8 mRNA levels had significantly poorer overall survival (OS) than those with high PD-1, PD-L1 and CD8 mRNA levels, respectively (p < 0.001, p < 0.01 and p < 0.05). Low PD-1, PD-L1 and CD8 mRNA levels were more significantly associated with poor prognosis in undifferentiated-type GC patients than in differentiated-type GC patients (PD-1: differentiated p = 0.0071 vs. undifferentiated p = 0.0024; PD-L1: p = 0.6527 vs. p < 0.0001; CD8: p = 0.4465 vs. p < 0.05). Multivariate analysis showed that lymph node metastasis, peritoneal dissemination, distant metastasis, low PD-1 mRNA levels and low CD8 mRNA levels were independent prognostic factors for worse OS (low PD-1 mRNA level: OR 2.16, 95% CI 1.10-4.58, p < 0.05; low CD8 mRNA level: OR 2.55, 95% CI 1.12-6.90, p < 0.05). PD-1 and PD-L1 mRNA levels in immune cells were significantly associated with PD-1 and PD-L1 protein levels (both p < 0.05), respectively. CONCLUSIONS: PD-1, PD-L1 and CD8 mRNA levels may reflect antitumor immunity in GC, and low PD-1 and CD8 mRNA levels are potential predictive biomarkers for poor prognosis in GC patients who underwent surgery.

Oncogenic splicing abnormalities induced by DEAD-Box Helicase 56 amplification in colorectal cancer.

Alternative splicing, regulated by DEAD-Box Helicase (DDX) families, plays an important role in cancer. However, the relationship between the DDX family and cancer has not been fully elucidated. In the present study, we identified a candidate oncogene DDX56 on Ch.7p by a bioinformatics approach using The Cancer Genome Atlas (TCGA) dataset of colorectal cancer (CRC). DDX56 expression was measured by RT-qPCR and immunochemical staining in 108 CRC patients. Clinicopathological and survival analyses were carried out using three CRC datasets. Biological roles of DDX56 were explored by gene set enrichment analysis (GSEA), and cell proliferation in vitro and in vivo, cell cycle assays, and using DDX56-knockdown or overexpressed CRC cells. RNA sequencing was carried out to elucidate the effect of DDX56 on mRNA splicing. We found that DDX56 expression was positively correlated with the amplification of DDX56 and was upregulated in CRC cells. High DDX56 expression was associated with lymphatic invasion and distant metastasis and was an independent poor prognostic factor. In vitro analysis, in vivo analysis and GSEA showed that DDX56 promoted proliferation ability through regulating the cell cycle. DDX56 knockdown reduced intron retention and tumor suppressor WEE1 expression, which functions as a G2-M DNA damage checkpoint. We have identified DDX56 as a novel oncogene and prognostic biomarker of CRC that promotes alternative splicing of WEE1.

Identification of ARL4C as a Peritoneal Dissemination-Associated Gene and Its Clinical Significance in Gastric Cancer.

BACKGROUND: In gastric cancer (GC), peritoneal dissemination (PD) occurs frequently and is incurable. In this study, we aimed to identify PD-associated genes in GC. METHODS: We identified a PD-associated gene using three GC datasets: highly disseminated peritoneal GC cell lines, the Singapore dataset and The Cancer Genome Atlas (TCGA) dataset. We assessed the clinicopathological significance of the gene expression using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and performed immunohistochemical analysis for the gene in our patient cohort. We also performed survival analyses of the gene in our patient cohort, the Singapore dataset and the GSE62254 datasets. Moreover, gene set enrichment analysis (GSEA) was performed using the Singapore and TCGA datasets. Finally, in vitro experiments such as invasion/migration assays, immunofluorescence staining of actin filaments, epidermal growth factor (EGF) treatment analysis, and gene expression analysis were conducted using three gene-knockdown GC cell lines (AGS, 58As9, MKN45). RESULTS: ADP-ribosylation factor-like 4c (ARL4C) was identified as a PD-associated gene, and immunohistochemical analysis showed that ARL4C was overexpressed in GC cells. High ARL4C expression was associated with the depth of invasion (p < 0.01) and PD (p < 0.05) and was a poor prognostic factor (p < 0.05) in our patient cohort, the Singapore dataset and the GSE62254 dataset. ARL4C expression positively correlated with the epithelial-mesenchymal transition (EMT) gene set in GSEA. Moreover, ARL4C knockdown reduced invasion/migration capacity, SLUG expression, and the formation of lamellipodia or filopodia in AGS and 58As9 cells. Finally, EGF treatment increased ARL4C expression in MKN45 cells. CONCLUSIONS: ARL4C was associated with PD and was a poor prognostic factor in GC, possibly through promoting invasive capacity by activation of both EMT and motility.

Identification of UHRF2 as a Negative Regulator of Epithelial-Mesenchymal Transition and Its Clinical Significance in Esophageal Squamous Cell Carcinoma.

OBJECTIVE: The involvement of epithelial-mesenchymal transition (EMT) in esophageal squamous cell carcinoma (ESCC) has not been fully elucidated. Here, we aimed to identify EMT-related genes associated with TGF-ß in ESCC and to clarify the role of these genes in the progression of ESCC. METHODS: EMT-related genes associated with TGF-ß expression were identified in patients with ESCC using microarray analysis and public datasets. The effects of ubiquitin-like with PHD and ring finger domains 2 (UHRF2) expression were analyzed in ESCC cell lines. Cell proliferation and invasion were measured using MTT and invasion assays, respectively. UHRF2 mRNA expression was also analyzed in 75 ESCC specimens to determine the clinical significance of UHRF2 in ESCC. RESULTS: Treatment of ESCC cell lines with TGF-ß increased UHRF2 expression. UHRF2 overexpression increased CDH1 (E-cadherin) expression and decreased invasive capacity. The 75 ESCC specimens were divided into the UHRF2 high-expression group (n = 61) and the UHRF2 low-expression group (n = 14). Low UHRF2 expression was significantly correlated with vascular invasion (p = 0.034) and was an independent prognostic factor for poor prognosis (p = 0.005). CONCLUSION: UHRF2 may be a negative regulator of EMT and a novel prognostic biomarker for ESCC.

Case report: A rare case of triple negative breast cancer with development of acute pancreatitis due to dexamethasone during adjuvant chemotherapy.

Here, we present the case of a 42-year-old female who developed acute pancreatitis due to dexamethasone during adjuvant chemotherapy for early triple negative breast cancer (TNBC). The patient received partial mastectomy and sentinel lymph node biopsy for early TNBC (cT1N0M0, cStage I) of the left breast. Dose-dense doxorubicin plus cyclophosphamide (ddAC) was administered as the adjuvant-chemotherapy; however, epigastralgia appeared on the fifth day of the first administration. A blood test showed a remarkable increase of serum pancreatic enzyme levels and computed tomography (CT) showed the swelling of pancreas and surrounding effusion, and she was diagnosed with moderate acute pancreatitis. As she had no history of excessive alcohol consumption or complication of cholelithiasis, dyslipidemia, or pancreatic neoplasm, drug-induced pancreatitis was suspected. Dexamethasone, which was administered as an antiemetic, was the suspected drug based on the drug administration history and previous report, and dexamethasone was discontinued from the second administration of ddAC. There was subsequently no recurrence of pancreatitis with no increase in serum pancreatic enzyme levels, and it was possible to complete adjuvant-chemotherapy. Alcohol, gallstones, dyslipidemia, and drugs have been reported as causes of pancreatitis; however, steroid-induced acute pancreatitis is extremely rare. We present the first case of acute pancreatitis induced by dexamethasone as the antiemetic.

A rare case of liver regenerative and non-neoplastic lesion resembling a well-differentiated hepatocellular carcinoma.

BACKGROUND: Nodular regenerative hyperplasia (NRH) is a rare disease that presents pathologically as diffuse hepatic nodules without fibrous septa. It is believed to be caused by vasculopathy against a background of various systemic diseases, such as hematologic, autoimmune, and drug-induced diseases, with various symptoms. In spite of the recent imaging advances, various atypical cases of nodular lesions are observed in daily clinical practice. Cases that do not completely meet these criteria are referred to as -like or -similar lesions in clinical situations, making it difficult to understand their pathogenesis. We present a case in which two hepatic nodular lesions were noted and difficult to differentiate from malignancy preoperatively. The lesions were laparoscopically resected and a pathological diagnosis with non-neoplastic liver regenerative nodules resembling NRH was made. CASE PRESENTATION: A 49-year-old man with no alcohol or drug intake and no past medical history was identified as having liver tumors on screening examination without any symptoms. Contrast-enhanced computed tomography (CT) showed two hepatic tumors; approximately 2-cm tumors at S7 and S8. Gadolinium-ethoxybenzyl-diethylenetriamine-pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) revealed fat inclusions in their contents. Ethoxybenzyl (EOB) uptake was also observed during the hepatobiliary phase. Based on preoperative examinations, we suspected well-differentiated hepatocellular carcinoma (HCC) and performed laparoscopic S7/8 partial resection for these lesions. Macroscopically, the resected specimens showed a non-cirrhotic yellowish-cut surface containing brownish, ill-defined lesions with irregular borders. Microscopically, these lesions showed zonal necrosis, congestion, and aggregation of hemosiderin-laden macrophages around the central vein. In these areas, the fatty deposition of hepatocytes was lower than that in the surrounding background hepatocytes. Histopathologically, neither neoplastic nor hyperplastic lesions were observed, and he was diagnosed as regenerative hepatic change with centrilobular necrosis. CONCLUSIONS: Considering the pathological results, these lesions were thought to be a type of NRH-like lesion with possible hepatic vessel disorder. However, the lesion's cause and classification was difficult to determine. The accumulation of these regenerative changes accompanying fatty liver is needed to clarify the mechanism and its clinical significance.

SHARPIN is a novel gene of colorectal cancer that promotes tumor growth potentially via inhibition of p53 expression.

Colorectal cancer (CRC) is widely prevalent and represents a significant contributor to global cancer­related mortality. There remains a pressing demand for advancements in CRC treatment modalities. The E3 ubiquitin ligase is a critical enzyme involved in modulating protein expression levels via posttranslational ubiquitin­mediated proteolysis, and it is reportedly involved in the progression of various cancers, making it a target of recent interest in anticancer therapy. In the present study, using comprehensive expression analysis involving spatial transcriptomic analysis with single­cell RNA sequencing in clinical CRC datasets, the ubiquitin­associated protein Shank­associated RH domain interactor (SHARPIN) was identified, located on amplified chromosome 8q, which could promote CRC progression. SHARPIN was found to be upregulated in tumor cells, with elevated expression observed in tumor tissues. This heightened expression of SHARPIN was positively associated with lymphatic invasion and served as an independent predictor of a poor prognosis in patients with CRC. In vitro and in vivo analyses using SHARPIN­overexpressing or ­knockout CRC cells revealed that SHARPIN overexpression upregulated MDM2, resulting in the downregulation of p53, while SHARPIN silencing or knockout downregulated MDM2, leading to p53 upregulation, which affects cell cycle progression, tumor cell apoptosis and tumor growth in CRC. Furthermore, SHARPIN was found to be overexpressed in several cancer types, exerting significant effects on survival outcomes. In conclusion, SHARPIN represents a newly identified novel gene with the potential to promote tumor growth following apoptosis inhibition and cell cycle progression in part by inhibiting p53 expression via MDM2 upregulation; therefore, SHARPIN represents a potential therapeutic target for CRC.

Spatial and single-cell colocalisation analysis reveals MDK-mediated immunosuppressive environment with regulatory T cells in colorectal carcinogenesis.

BACKGROUND: Cell-cell interaction factors that facilitate the progression of adenoma to sporadic colorectal cancer (CRC) remain unclear, thereby hindering patient survival. METHODS: We performed spatial transcriptomics on five early CRC cases, which included adenoma and carcinoma, and one advanced CRC. To elucidate cell-cell interactions within the tumour microenvironment (TME), we investigated the colocalisation network at single-cell resolution using a deep generative model for colocalisation analysis, combined with a single-cell transcriptome, and assessed the clinical significance in CRC patients. FINDINGS: CRC cells colocalised with regulatory T cells (Tregs) at the adenoma-carcinoma interface. At early-stage carcinogenesis, cell-cell interaction inference between colocalised adenoma and cancer epithelial cells and Tregs based on the spatial distribution of single cells highlighted midkine (MDK) as a prominent signalling molecule sent from tumour epithelial cells to Tregs. Interaction between MDK-high CRC cells and SPP1+ macrophages and stromal cells proved to be the mechanism underlying immunosuppression in the TME. Additionally, we identified syndecan4 (SDC4) as a receptor for MDK associated with Treg colocalisation. Finally, clinical analysis using CRC datasets indicated that increased MDK/SDC4 levels correlated with poor overall survival in CRC patients. INTERPRETATION: MDK is involved in the immune tolerance shown by Tregs to tumour growth. MDK-mediated formation of the TME could be a potential target for early diagnosis and treatment of CRC. FUNDING: Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for Science Research; OITA Cancer Research Foundation; AMED under Grant Number; Japan Science and Technology Agency (JST); Takeda Science Foundation; The Princess Takamatsu Cancer Research Fund.

Clinicopathological features of primary leiomyosarcoma of the gastrointestinal tract following recognition of gastrointestinal stromal tumours.

AIMS: We aimed to elucidate the clinicopathological and immunohistochemical features of leiomyosarcoma (LMS) of the gastrointestinal (GI) tract. METHODS AND RESULTS: We encountered seven cases of GI-LMS in the colon (n = 4), rectum (n = 1), jejunum (n = 1) and stomach (n = 1). They ranged from 1 to 25 cm (median, 8.5 cm) in size and had high mitotic counts (median 38 per 50 high-power fields). Morphologically, the tumours were composed mainly of spindle cells with eosinophilic cytoplasm and various degrees of nuclear atypia and pleomorphism. Immunohistochemically, the tumours were positive for α-smooth muscle actin (86%), muscle-specific actin (71%), desmin (86%), calponin (71%), h-caldesmon (57%) and smoothelin (71%). All were negative for KIT, CD34, protein kinase C theta and DOG1. Local recurrence and distant metastasis occurred in one and three patients, respectively. We then reviewed 55 cases of GI-LMS from the era following the recognition of gastrointestinal stromal tumours. Among 29 of 55 cases for whom follow-up information was available, the estimated 5-year overall survival rate was 51.6%; tumour size ≥5 cm was correlated significantly with shorter overall survival time (P = 0.0016), while mitotic count (≥50 or ≥100 per 50 high-power fields) proved to be no prognostic factor. CONCLUSIONS: GI-LMSs have distinctive clinicopathological and immunohistochemical features and exhibit aggressive biological behaviour.