Oncofetal IGF2BP3-mediated control of microRNA structural diversity in the malignancy of early-stage lung adenocarcinoma.

The nature of microRNA (miRNA) dysfunction in carcinogenesis remains controversial because of the complex connection between miRNA structural diversity and biological processes. Here, we found that oncofetal IGF2BP3 regulates the selective production of a subset of 3'-isoforms (3'-isomiRs), including miR-21-5p and Let-7 family, which induces significant changes in their cellular seed occupancy and structural components, establishing a cancer-specific gene expression profile. The D-score, reflecting dominant production of a representative miR-21-5p+C (a 3'-isomiR), discriminated between clinical early-stage lung adenocarcinoma (LUAD) cases with low and high recurrence risks, and was associated with molecular features of cell cycle progression, epithelial-mesenchymal transition pressure, and immune evasion. We found that IGF2BP3 controls the production of miR-21-5p+C by directing the nuclear Drosha complex to select the cleavage site. IGF2BP3 was also involved in the production of 3'-isomiRs of miR-425-5p and miR-454-3p. IGF2BP3-regulated these three miRNAs are suggested to be associated with the regulation of p53, TGF-ß, and TNF pathways in LUAD. Knockdown of IGF2BP3 also induced a selective upregulation of Let-7 3'-isomiRs, leading to increased cellular Let-7 seed occupancy and broad repression of its target genes encoding cell cycle regulators. The D-score is an index that reflects this cellular situation. Our results suggest that the aberrant regulation of miRNA structural diversity is a critical component for controlling cellular networks, thus supporting the establishment of a malignant gene expression profile in early stage LUAD.

Prevalence and outcomes of germline pathogenic variants of homologous recombination repair genes in ovarian cancer.

Germline pathogenic variants (PVs) are pivotal in gynecological oncology. We focused on the prevalence, clinicopathological features, and survival impact of homologous recombination repair (HRR) PVs in patients with epithelial ovarian cancer (EOC). This was a multicenter retrospective cohort study, and 1248 patients with EOC were registered. Eligible patients (n = 1112) underwent germline DNA analysis for 26 cancer predisposition genes, including nine HRR-related genes, such as BRCA1/2, BRIP1, PALB2, RAD51C/D, and ATM. The associations between clinicopathological factors and HRR-related PVs were examined. Kaplan-Meier and Cox regression analyses were conducted. Among 1091 analyzed patients, 153 (14.0%) carried PVs and 140 (12.8%) were HRR-related. HRR-PV-positive status significantly correlated with serous carcinoma (22.9% vs. 4.8%, P < 0.0001) and advanced disease (18.5% vs. 5.9%, P < 0.0001). The HRR-PV-positive group exhibited higher prevalence of personal breast (12.9%) and familial breast/ovarian (29.2%) cancer history. HRR status independently improved overall survival in stage III/IV disease (P = 0.04) but not progression-free survival. HRR-related germline PVs exhibit distinct clinicopathological features with survival implications. Variants were significantly associated with serous carcinoma and advanced disease, underscoring the importance of genetic testing to develop individualized EOC treatment strategies. Considering the study period (2000-2019), the limited use of bevacizumab and poly (ADP-ribose) polymerase inhibitors as maintenance therapy should be recognized.

TGFß-Responsive Stromal Activation Occurs Early in Serrated Colorectal Carcinogenesis.

Activated TGFß signaling in the tumor microenvironment, which occurs independently of epithelial cancer cells, has emerged as a key driver of tumor progression in late-stage colorectal cancer (CRC). This study aimed to elucidate the contribution of TGFß-activated stroma to serrated carcinogenesis, representing approximately 25% of CRCs and often characterized by oncogenic BRAF mutations. We used a transcriptional signature developed based on TGFß-responsive, stroma-specific genes to infer TGFß-dependent stromal activation and conducted in silico analyses in 3 single-cell RNA-seq datasets from a total of 39 CRC samples and 12 bulk transcriptomic datasets consisting of 2014 CRC and 416 precursor samples, of which 33 were serrated lesions. Single-cell analyses validated that the signature was expressed specifically by stromal cells, effectively excluding transcriptional signals derived from epithelial cells. We found that the signature was upregulated during malignant transformation and cancer progression, and it was particularly enriched in CRCs with mutant BRAF compared to wild-type counterparts. Furthermore, across four independent precursor datasets, serrated lesions exhibited significantly higher levels of TGFß-responsive stromal activation compared to conventional adenomas. This large-scale analysis suggests that TGFß-dependent stromal activation occurs early in serrated carcinogenesis. Our study provides novel insights into the molecular mechanisms underlying CRC development via the serrated pathway.

[Regulation of the Tumor Microenvironment through HER2 Signaling-Insights from Gastric Cancer Cases with Heterogeneous HER2 Overexpression].

HER2, a member of the human epidermal growth factor receptor(HER)family, exhibits gene amplification, protein overexpression, or both in 13-27% of gastric cancer(GC)cases. Through the activation of downstream Akt and ERK pathways, HER2 promotes the survival and proliferation of gastric cancer cells. The impact of HER2 signaling on the tumor microenvironment(TME)in GC remains unclear, and the heterogeneity of HER2 overexpression in GC tissues is considered a contributing factor. In this study, we focused on differences in the TME between HER2-positive and HER2-negative areas in HER2-positive GC and found that HER2 signaling, particularly the HER2-Akt cascade, may suppress stimulator of interferon genes (STING)expression and reduce CD8+ T cell infiltration in tumor cells. Overall, our findings suggest the potential for a novel therapeutic approach to activate the anti-tumor immune response in HER2-positive GC.

The tumor cell-intrinsic cGAS-STING pathway is associated with the high density of CD8+ T cells after chemotherapy in esophageal squamous cell carcinoma.

BACKGROUND: Chemotherapy has the potential to induce CD8+ T-cell infiltration in the tumor microenvironment (TME) and activate the anti-tumor immune response in several cancers including esophageal squamous cell carcinoma (ESCC). The tumor cell-intrinsic cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway has been known as a critical component for regulating immune cell activation in the TME. However, its effect on the infiltration of immune cells induced by chemotherapy in the ESCC TME has not been investigated. METHODS: We examined the effect of the tumor-cell intrinsic cGAS-STING pathway on the infiltration of CD8+ T cells induced by chemotherapy in ESCC using ESCC cell lines and surgically resected ESCC specimens from patients who received neoadjuvant chemotherapy (NAC). RESULTS: We found that chemotherapeutic agents, including 5-fluorouracil (5-FU) and cisplatin (CDDP), activated the cGAS-STING pathway, consequently inducing the expression of type I interferon and T-cell-attracting chemokines in ESCC cells. Moreover, the tumor cell-intrinsic expression of cGAS-STING was significantly and positively associated with the density of CD8+ T cells in ESCC after NAC. However, the tumor cell-intrinsic expression of cGAS-STING did not significantly impact clinical outcomes in patients with ESCC after NAC. CONCLUSION: Our findings suggest that the tumor cell-intrinsic cGAS-STING pathway might contribute to chemotherapy-induced immune cell activation in the ESCC TME.

M2 tumor-associated macrophages resist to oxidative stress through heme oxygenase-1 in the colorectal cancer tumor microenvironment.

M2 tumor-associated macrophages (M2-TAMs) promote cancer cell proliferation and metastasis in the TME. Our study aimed to elucidate the mechanism of increased frequency of M2-TAMs infiltration in the colorectal cancer (CRC)-TME, focusing on the resistance to oxidative stress through nuclear factor erythroid 2-related factor 2 (Nrf2) pathway. In this study, we evaluated the correlation between M2-TAM signature and mRNA expression of antioxidant related genes using public datasets, and the expression level of antioxidants in M2-TAMs by flow cytometry and the prevalence of M2-TAMs expressing antioxidants by immunofluorescence staining using surgically resected specimens of CRC (n = 34). Moreover, we generated M0 and M2 macrophages from peripheral blood monocytes and evaluated their resistance to oxidative stress using the in vitro viability assay. Analysis of GSE33113, GSE39582, and The Cancer Genome Atlas (TCGA) datasets indicated that mRNA expression of HMOX1 (heme oxygenase-1 (HO-1)) was significantly positively correlated with M2-TAM signature (r = 0.5283, r = 0.5826, r = 0.5833, respectively). The expression level of both Nrf2 and HO-1 significantly increased in M2-TAMs compared to M1- and M1/M2-TAMs in the tumor margin, and the number of Nrf2+ or HO-1+M2-TAMs in the tumor stroma significantly increased more than those in the normal mucosa stroma. Finally, generated M2 macrophages expressing HO-1 significantly resisted to oxidative stress induced by H2O2 in comparison with generated M0 macrophages. Taken together, our results suggested that an increased frequency of M2-TAMs infiltration in the CRC-TME is related to Nrf2-HO-1 axis mediated resistance to oxidative stress.

ARID1A deficiency is targetable by AKT inhibitors in HER2-negative gastric cancer.

BACKGROUND: The PI3K/AKT signaling pathway is frequently activated in gastric cancer (GC); however, AKT inhibitors are not effective in unselected GC patients in clinical trials. Mutations in AT-rich interactive domain 1A (ARID1A), which are found in approximately 30% of GC patients, activate PI3K/AKT signaling, suggesting that targeting the ARID1A deficiency-activated PI3K/AKT pathway is a therapeutic candidate for ARID1A-deficient GC. METHODS: The effect of AKT inhibitors was evaluated using cell viability and colony formation assays in ARID1A-deficient and ARID1A knockdown ARID1A-WT GC cells as well as in HER2-positive and HER2-negative GC. The Cancer Genome Atlas cBioPortal and Gene Expression Omnibus microarray databases were accessed to determine the extent of dependence of GC cell growth on the PI3K/AKT signaling pathway. RESULTS: AKT inhibitors decreased the viability of ARID1A-deficient cells and the inhibitory effect was greater in ARID1A-deficient/HER2-negative GC cells. Bioinformatics data suggested that PI3K/AKT signaling plays a greater role in proliferation and survival in ARID1A-deficient/HER2-negative GC cells than in ARID1A-deficient/HER2-positive cells, supporting the higher therapeutic efficacy of AKT inhibitors. CONCLUSIONS: The effect of AKT inhibitors on cell proliferation and survival is affected by HER2 status, providing a rationale for exploring targeted therapy using AKT inhibitors in ARID1A-deficient/HER2-negative GC.

Down-regulation of stimulator of interferon genes (STING) expression and CD8+ T-cell infiltration depending on HER2 heterogeneity in HER2-positive gastric cancer.

BACKGROUND: HER2 signaling might be involved in the regulation of immune cell activation in the tumor microenvironment (TME) of gastric cancer (GC). However, the relationship between HER2 status and immune cell condition in the HER2-positive GC TME is not clearly understood. METHODS: To investigate the effect of HER2 signaling on the activation of the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway, which contributes to immune cell activation in the GC TME, we evaluated the associations among the expressions of HER2, cGAS-STING, and the number of CD8+ tumor-infiltrating lymphocytes (TIL) by considering HER2 heterogeneity in HER2-positive GC tissues. We also examined the effect of HER2 signaling on the activation of STING signaling in vitro using human HER2-positive GC cell lines. RESULTS: The expression of HER2 is highly heterogeneous in HER2-positive GC tissues, and we found that the number of CD8+ TIL in HER2 high areas was significantly lower than that in HER2 low areas in HER2-positive GC tissues. Intriguingly, the tumor cell-intrinsic expression of STING, but not cGAS, was also significantly lower in the HER2 high areas than the HER2 low areas in HER2-positive GC tissues. Moreover, in vitro experiments, we demonstrated that the blockade of HER2 signaling increased the expression of STING and its target genes, including IFNB1, CXCL9/10/11, and CCL5, in HER2-positive GC cell lines. CONCLUSIONS: Our results suggest that HER2 signaling might suppress immune cell activation in the GC TME by inhibiting STING signaling in tumor cells in HER2-positive GC.

[Remodeling of the Tumor Microenvironment by Radiotherapy through the cGAS-STING Pathway in Esophageal Squamous Cell Carcinoma].

It has been reported that tumor cell-intrinsic cyclic GMP-AMP synthase(cGAS)-stimulator of interferon genes(STING) pathway is essential for radiotherapy(RT)-induced activation of anti-tumor immune responses. However, its role in the RT- induced remodeling of the tumor microenvironment(TME)in esophageal squamous cell carcinoma(ESCC), is largely unknown. In this study, we found that the tumor cell-intrinsic cGAS-STING pathway is a critical component for RT-induced activation of immune cells in the TME through the induction of type Ⅰ interferon and C-X-C motif chemokine ligand 10 in tumor cells in ESCC. However, at the same time, the tumor cell-intrinsic cGAS-STING pathway is also involved in RT-triggered infiltration and polarization of immunosuppressive CD163+ tumor-associated macrophages (TAM) through the induction of interleukin 34 (IL-34) in tumor cells in ESCC. Our findings suggest that targeting IL-34 to impede the infiltration and polarization of CD163+ TAM could potentially enhance the efficacy of RT-induced immune cell activation in ESCC TME.

SH2D4A downregulation due to loss of chromosome 8p is associated with poor prognosis and low T cell infiltration in colorectal cancer.

BACKGROUND: Colorectal cancer (CRC) develops through chromosomal instability (CIN) or microsatellite instability (MSI) due to deficient mismatch-repair (dMMR). We aimed to characterise novel cancer-associated genes that are downregulated upon malignant transformation in microsatellite stable (MSS) CRCs, which typically exhibit CIN with proficient mismatch-repair (pMMR). METHODS: Comprehensive screening was conducted on adenomas, MSI/MSS CRCs and cell lines, followed by copy number analysis, and their genetic and prognostic relevance was confirmed in microarray and RNA-seq cohorts (n = 3262, in total). Immunohistochemistry for SH2D4A was performed in 524 specimens of adenoma, carcinoma in situ and dMMR/pMMR CRC. The functional role of SH2D4A was investigated using CRC cell lines. RESULTS: A set of 11 genes, including SH2D4A, was downregulated during the adenoma-carcinoma sequence in MSS/CIN CRCs, mainly due to chromosome 8p deletions, and their negative prognostic impact was validated in independent cohorts. All adenomas were SH2D4A positive, but a subset of CRCs (5.3%) lacked SH2D4A immunohistochemical staining, correlating with poor prognosis and scarce T cell infiltration. SH2D4A depletion did not affect cell proliferation or IL-6-induced STAT3 phosphorylation. CONCLUSIONS: Our findings suggest that downregulation of multiple genes on chromosome 8p, including SH2D4A, cooperatively contribute to tumorigenesis, resulting in the immune cold tumour microenvironment and poor prognosis.

Immune escape mechanism behind resistance to anti-PD-1 therapy in gastrointestinal tract metastasis in malignant melanoma patients with multiple metastases.

Immunotherapy targeting the PD-1 axis has recently become a standard treatment for patients with malignant melanoma. However, approximately 25% of reported malignant melanoma patients who initially responded to immunotherapy with anti-PD-1 mAb had progressive disease, and the immune escape mechanism behind resistance to anti-PD-1 therapy is not yet fully understood in the clinical setting. In the present study, we included four malignant melanoma patients, in whom multiple metastases other than gastrointestinal tract metastasis had disappeared or were controlled under multidisciplinary treatment that included anti-PD-1 therapy. Using IHC, we evaluated the immune status of surgically resected specimens of gastrointestinal tract metastases as acquired resistant lesion to anti-PD-1 therapy. We herein report that the down-regulated expression of HLA class I and up-regulated expression of inhibitory immune checkpoint ligands, CD155 (ligand for T cell immunoglobulin and ITIM domain, TIGIT) and carcinoembryonic antigen-related adhesion molecule-1 (ligand for TIM-3), were observed on the tumor cells in the metastatic gastrointestinal tract tumors. Moreover, our results also suggest that stromal TGF-ß may be related to this down-regulation of HLA class I expression on the tumor cells. In conclusion, it is likely that the down-regulated expression of HLA class I and additional expression of inhibitory immune checkpoint ligands other than PD-L1 on the tumor cells were acquired in the gastrointestinal tract metastasis during anti-PD-1 therapy in the malignant melanoma patients.

Role of the cGAS-STING pathway in regulating the tumor-immune microenvironment in dMMR/MSI colorectal cancer.

Deficient mismatch repair (dMMR)/microsatellite instability (MSI) colorectal cancer (CRC) has high immunogenicity and better prognosis compared with proficient MMR (pMMR)/microsatellite stable (MSS) CRC. Although the activation of the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway has been considered to contribute to the high number of CD8+ TILs, its role in dMMR/MSI CRC is largely unknown. In this study, to examine the role of the cGAS-STING pathway on the recruitment of CD8+ TILs in dMMR/MSI CRC, we used public datasets and clinical tissue samples in our cohorts to evaluate the expression of cGAS, STING, and CD8+ TILs in pMMR/MSS and dMMR/MSI CRCs. According to the analysis of public datasets, the expression of cGAS-STING, CD8 effector gene signature, and CXCL10-CCL5, chemoattractants for CD8+ TILs which regulated by the cGAS-STING pathway, was significantly upregulated in dMMR/MSI CRC, and the expression of cGAS-STING was significantly associated with the expression of CD8 effector gene signature. Immunohistochemistry staining of the clinical tissue samples (n = 283) revealed that cGAS-STING was highly expressed in tumor cells of dMMR CRC, and higher expression of cGAS-STING in tumor cells was significantly associated with the increased number of CD8+ TILs. Moreover, we demonstrated that the downregulation of MMR gene in human CRC cell lines enhanced the activation of the cGAS-STING pathway. Taken together, for the first time, we found that dMMR/MSI CRC has maintained a high level of cGAS-STING expression in tumor cells, which might contribute to abundant CD8+ TILs and immune-active TME.

Incidence of upper extremity deep vein thrombosis in the retrosternal reconstruction after esophagectomy.

BACKGROUND: Upper extremity deep vein thrombosis (UEDVT) is relatively rare but cannot be negligible because it can cause fatal complications. Although it is reported that the occurrence rate of UEDVT has increased due to central venous catheter (CVC), cancer, and surgical invasion, there is still limited information for esophagectomy. The aim of this study was to evaluate the clinical factors, including CVC placement and thromboprophylaxis approach, as well as retrosternal space's width as a predictive factor for UEDVT in patients receiving esophagectomy. METHODS: This study included 66 patients who underwent esophagectomy with retrosternal reconstruction using a gastric tube. All patients routinely underwent contrast-enhanced computed tomography (CT) on the 4th postoperative day. Low-molecular-weight-heparin (LMWH) was routinely administered by the 2nd postoperative day. To evaluate retrosternal space's width, (a) The distance from sternum to brachiocephalic artery and (b) the distance from sternum to vertebra were measured by preoperative CT, and the ratio of (a) to (b) was defined as the width of retrosternal space. RESULTS: Among all patients, 11 (16.7%) suffered from UEDVT, and none was preoperatively received CVC placement, while 7 were inserted in non-UEDVT cases. Retrosternal space's width in patients with UEDVT was significantly smaller than that in patients without UEDVT (0.17 vs. 0.26; P < 0.0001). A cutoff value of the width was 0.21, which has high sensitivity (87%) and specificity (82%) for UEDVT prediction, respectively. CONCLUSION: The existence of CVC may not affect the development of UEDVT, but preoperative evaluation of retrosternal ratio may predict the occurrence of UEDVT.

ARID1A deficiency in EBV-positive gastric cancer is partially regulated by EBV-encoded miRNAs, but not by DNA promotor hypermethylation.

AT-rich interactive domain 1A (ARID1A), which is a tumor suppressor gene, is frequently mutated in Epstein-Barr virus-positive gastric cancer [EBV (+) GC]. While most ARID1A mutations in GC are truncating mutations, leading to loss of ARID1A protein expression, epigenetic modifications appear to contribute to ARID1A deficiency in EBV (+) GC harboring wild-type ARID1A. Based on the significant role of epigenetic modifications in EBV (+) GC that contributes to ARID1A deficiency, the methylation status of ARID1A was evaluated in EBV-infected cells and GC patients using a publicly available microarray and the Cancer Genome Atlas (TCGA) database. EBV-encoded miRNAs that potentially target ARID1A were identified as an additional epigenetic modulator by computational prediction. In vitro experiments were conducted to evaluate how EBV-encoded miRNAs affected ARID1A mRNA and protein levels. In clinical GC samples, the expression of predicted miRNAs and ARID1A and the mutation status of ARID1A was evaluated. As results, ARID1A was not hypermethylated in EBV (+) GC samples or EBV-infected GC cells. EBV infection did not alter ARID1A mRNA levels, suggesting that ARID1A protein deficiency was caused by post-transcriptional gene silencing in ARID1A-WT EBV (+) GC. Overexpression of miR-BART11-3p and miR-BART12, which were identified as miRNAs that potentially bind ARID1A, suppressed ARID1A protein expression in MKN7 and NCI-N87 cells. Highly expressed miR-BART11-3p and miR-BART12 were correlated with decreased ARID1A levels in GC tumors which did not harbor ARID1A mutations. The present findings revealed that ARID1A expression was epigenetically regulated by miR-BART11-3p and miR-BART12 in EBV (+) GC.

Therapeutic potential of anti-VEGF receptor 2 therapy targeting for M2-tumor-associated macrophages in colorectal cancer.

BACKGROUND: Although immunotherapy with immune checkpoint inhibitors (ICIs) has become a standard therapeutic strategy in colorectal cancer (CRC) exhibiting microsatellite instability-high, limited patients benefit from this new approach. To increase the efficacy of ICIs in CRC patients, it is crucial to control the function of immunosuppressive cells in the tumor microenvironment. M2-tumor-associated macrophages (TAMs) are key immunosuppressive cells and promote tumor growth, angiogenesis, and epithelial-mesenchymal transition. In the present study, we focused on the VEGF signaling pathway in M2-TAMs to control their inhibitory function. METHODS: We evaluated the population of M2-TAMs, the VEGF receptor 2 (VEGFR2) expression on M2-TAMs, and the correlation between HIF-1α-positive cells and VEGFR2 expression levels on M2-TAMs in CRC using the analysis of The Cancer Genome Atlas colorectal adenocarcinoma dataset (n = 592), the flow cytometry of freshly resected surgical specimens of CRC (n = 20), and the immunofluorescence staining of formalin-fixed paraffin-embedded whole tissue samples of CRC (n = 20). Furthermore, we performed a functional assay of M2 macrophages through the VEGF/VEGFR2 signaling pathway in vitro. RESULTS: The population of M2-TAMs and their VEGFR2 expression significantly increased in the tumor compared to the normal mucosa in the CRC patients. HIF1-α-positive cells significantly correlated with the VEGFR2 expression level of M2-TAMs. M2 macrophages induced by cytokines in vitro produced TGF-ß1 through the VEGF/VEGFR2 signaling pathway. CONCLUSIONS: Our results suggest that anti-VEGFR2 therapy may have therapeutic potential to control the immune inhibitory functions of M2-TAMs in CRC, resulting in enhanced efficacy of immunotherapy with ICIs.

Collision of Epstein-Barr virus-positive and -negative gastric cancer, diagnosed by molecular analysis: a case report.

BACKGROUND: Epstein-Barr virus (EBV)-positive gastric carcinoma (GC) is defined by the proliferation of GC cells with EBV infection. The co-existence of EBV-positive and -negative components in a single GC is rare. We report a case of GC with the co-existence of EBV-positive and EBV-negative components, in which we performed-for the first time-various molecular analyses to elucidate their histogenesis. CASE PRESENTATION: An 81-year-old man was diagnosed with GC based on the results of endoscopy and a pathological examination of the biopsy specimen. Systemic chemotherapy was performed, since lymph node and lung metastases were diagnosed based on computed tomography. Total gastrectomy and lymph node dissection were performed after chemotherapy, after confirming that the size of the metastatic lymph nodes had decreased and that the lung metastasis had disappeared. Grossly, a type 3 tumor was located in the middle posterior part of the stomach body. At the cut section, the tumor consisted of a white and solid part on the anal side of the tumor and a flat and elevated part on the oral side. Histologically, the former part consisted of GC with lymphoid stroma and the latter part was composed of poorly differentiated adenocarcinoma without prominent lymphocytic infiltration. The two histopathological components were clearly separated from each other. On EBV-encoded small RNA (EBER)-in situ hybridization (ISH), the part with the lymphoid stroma component was positive, while the other part was negative. Immunohistochemistry revealed that both components showed the overexpression of p53. Sequencing of TP53 using DNA extracted from the two components was conducted, and revealed different patterns. Targeted next generation sequencing revealed MYC amplification in the EBV-positive component of the tumor and HER2 amplification in the EBV-negative part. Immunohistochemistry revealed that the EBV-positive part was C-MYC( +)/HER2(-) and the EBV-negative part was C-MYC(-)/HER2( +). Correspondingly, chromogenic ISH and dual-color ISH showed amplification of C-MYC and no amplification of HER2 in the EBV-positive part, and no amplification of C-MYC and amplification of HER2 in the EBV-negative part. CONCLUSION: We presented a case of collision of two different GCs composed of EBER-ISH ( +)/C-MYC ( +) and EBER-ISH (-)/HER2 ( +) cells.

Landscape of EBV-positive gastric cancer.

Epstein-Barr virus-positive gastric cancer [EBV (+) GC] is associated with EBV infection and is one of the GC subtypes defined by the Cancer Genome Atlas. EBV (+) GC has several distinct genomic or epigenomic features and clinicopathological characteristics compared with other molecular subtypes of GC. Here, we summarize the unique features of EBV (+) GC including the clinical and histopathological features, and discuss associated genetic and epigenetic aberrations. We also discuss noncoding RNAs [EBV-encoded RNAs and EBV-encoded microRNAs (miRNAs)] derived from EBV-infected cells, which have not been described in detail previously. These noncoding RNAs are defined by their roles; for example, EBV-encoded miRNAs play pivotal roles in oncogenesis and tumor progression in EBV (+) GC. We also discuss recent advances in therapeutic modalities for EBV (+) GC, as well as the potential of EBV infection as a predictive biomarker of the response to anti-PD-1 therapy with immune checkpoint inhibitors. We introduce our recent studies focusing on AT-rich interactive domain 1A gene mutations and programmed death ligand-1 overexpression/CD274 copy-number amplification, which are recurrently identified in EBV (+) GC. Finally, based on those findings, we propose potential therapeutic options using candidate-targeted therapies against EBV (+) GC.

Selective sensitivity of EZH2 inhibitors based on synthetic lethality in ARID1A-deficient gastric cancer.

BACKGROUND: AT-rich interactive domain 1A (ARID1A) is a tumor suppressor gene that is frequently mutated in gastric cancer (GC). Although ARID1A mutations are not a druggable target for conventional treatments, novel therapeutic strategies based on a synthetic lethal approach are effective for ARID1A-deficient cancers. The histone methyltransferase EZH2 acts in a synthetic lethal manner in ARID1A-mutated ovarian cancer, although its role in GC remains unknown. METHODS: The selective sensitivity of the EZH2 inhibitors for ARID1A-deficient GC cells was evaluated using cell viability and colony formation assays. The expression of PI3K/AKT signaling genes were investigated using TCGA's cBioPortal database to determine whether the homeostasis between ARID1A and EZH2 is related to cell proliferation and survival via the PI3K/AKT signaling pathway. We also evaluated the phosphorylation of PI3K/AKT signaling proteins in ARID1A knock downed ARID1A-WT GC cells. RESULTS: EZH2 inhibitors decreased the viability of ARID1A-deficient cells in a dose-dependent manner and demonstrated the selective sensitivity to ARID1A-deficient cells in vitro experiment system. Bioinformatics approach revealed that the PI3K/AKT signaling was tended to be activated in ARID1A-deficient GC enhancing cell viability and, furthermore, down-regulation of EZH2 in ARID1A-deficient GC was related to normalization of PI3K/AKT signaling pathway. The cell experiment revealed that phosphorylated AKT was upregulated in ARID1A-deficent GC cells. CONCLUSIONS: The present findings provide a rationale for the selective sensitivity of EZH2 inhibitors against ARID1A-deficient GC and suggest the potential efficacy of targeted therapy using EZH2 inhibitors in this patient population.

[Significance and Treatment Strategy of Glasgow Prognostic Score in High Risk Stage â ¡ Colorectal Cancer].

In this study, we investigated the usefulness of Glasgow prognostic score(GPS)as a prognostic factor for Stage Ⅱ colorectal cancer, and the treatment strategy by individualizing adjuvant chemotherapy. We enrolled 86 patients with Stage Ⅱ primary colorectal cancer who underwent curative resection. This study examines the prognostic significance of clinicopathological factors and GPS, NLR, LMR, PLR. Multivariate analyses was performed to evaluate the factors affecting recurrence free survival. The 5-year OS was 92.5%, and the RFS was 86% in Stage Ⅱ colorectal cancer. The recurrence rate was 12.8%. In multivariate analysis, GPS(HR: 13.66, p=0.005)was extracted as an independent poor prognosis factor. In comparison of survival rates, RFS of GPS 0, 1 was 95.2% and that of GPS 2 43.8%, and GPS 2 had a significantly poor prognosis(p< 0.01). GPS 2 is an independent high risk factor for recurrence of Stage Ⅱ colorectal cancer. In order to improve the prognosis of Stage Ⅱ colorectal cancer, individualized adjuvant chemotherapy is important.

[Immunotherapy Targeting Tumor-Associated Carbohydrate Antigens in Deficient Mismatch Repair Colorectal Cancer].

The Tn antigen is the most prevalent tumor-associated carbohydrate antigen. It interacts with macrophage galactose-specific lectin(MGL)on dendric cells and macrophages, driving immune inhibitory signals. Colorectal cancer(CRC)exhibiting deficient mismatch repair(dMMR)is characterized by tumor-infiltrating lymphocytes(TILs), the expression of immune checkpoint molecules, and immune evasion. We recently reported that Tn antigen expression was associated with dMMR and that dMMR CRCs with strong Tn antigen expression demonstrated CD8+ T cell exclusion and a lack of PD-L1 expression. Our findings suggest that the immune cold subset of dMMR CRCs with strong Tn antigen may be effectively treated with immune checkpoint blockade therapy or cellular immunotherapy targeting Tn antigens.