TGFβ-Responsive Stromal Activation Occurs Early in Serrated Colorectal Carcinogenesis

Activated TGFβ 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 TGFβ-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 TGFβ-responsive, stroma-specific genes to infer TGFβ-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 TGFβ-responsive stromal activation compared to conventional adenomas. This large-scale analysis suggests that TGFβ-dependent stromal activation occurs early in serrated carcinogenesis. Our study provides novel insights into the molecular mechanisms underlying CRC development via the serrated pathway.

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.

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.

TIM-3 Expression and M2 Polarization of Macrophages in the TGFβ-Activated Tumor Microenvironment in Colorectal Cancer

TGFβ signaling in the tumor microenvironment (TME) drives immune evasion and is a negative predictor of immune checkpoint inhibitor (ICI) efficacy in colorectal cancer (CRC). TIM-3, an inhibitory receptor implicated in anti-tumor immune responses and ICI resistance, has emerged as an immunotherapeutic target. This study investigated TIM-3, M2 macrophages and the TGFβ-activated TME, in association with microsatellite instability (MSI) status and consensus molecular subtypes (CMSs). Transcriptomic cohorts of CRC tissues, organoids and xenografts were examined (n = 2240). TIM-3 and a TGFβ-inducible stromal protein, VCAN, were evaluated in CRC specimens using immunohistochemistry (n = 45). TIM-3 expression on monocytes and generated M2 macrophages was examined by flow cytometry. We found that the expression of HAVCR2 (TIM-3) significantly correlated with the transcriptional signatures of TGFβ, TGFβ-dependent stromal activation and M2 macrophage, each of which were co-upregulated in CMS4, CMS1 and MSI CRCs across all datasets. Tumor-infiltrating TIM-3+ immune cells accumulated in TGFβ-responsive cancer stroma. TIM-3 was increased on M2-polarized macrophages, and on monocytes in response to TGFβ treatment. In conclusion, we identified a close association between TIM-3 and M2-like polarization of macrophages in the TGFβ-rich TME. Our findings provide new insights into personalized immunotherapeutic strategies based on the TME for CRCs.

[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.

A Potential Biomarker of Dynamic Change in Peripheral CD45RA-CD27+CD127+ Central Memory T Cells for Anti-PD-1 Therapy in Patients with Esophageal Squamous Cell Carcinoma

In order to develop a biomarker predicting the efficacy of treatments for patients with esophageal squamous cell carcinoma (ESCC), we evaluated the subpopulation of T cells in ESCC patients treated with chemotherapy (CT), chemoradiotherapy (CRT), and nivolumab therapy (NT). Fifty-five ESCC patients were enrolled in this study, and peripheral blood samples were collected before and after CT or CRT and during NT. Frequencies of memory, differentiated, and exhausted T cells were evaluated using flow cytometry among cStages, treatment strategies, pathological responses of CT/CRT, and during NT. The frequencies of PD-1⁺ or TIM-3⁺CD4⁺ T cells were significantly higher in patients with cStage IV. PD-1⁺CD4⁺ and TIM-3⁺CD8⁺ T-cell populations were significantly higher in patients treated with CRT but were not associated with treatment response. The frequencies of both CD4⁺ and CD8⁺ CD45RA^-CD27⁺CD127⁺ central memory T cells (T_CM) were significantly decreased during the course of NT in the progressive disease group. Taken together, the alteration in frequency of CD45RA^-CD27⁺CD127⁺ T_CM during NT may be a biomarker to predict its therapeutic response in ESCC patients.

The Impact of Tumor Cell-Intrinsic Expression of Cyclic GMP-AMP Synthase (cGAS)-Stimulator of Interferon Genes (STING) on the Infiltration of CD8+ T Cells and Clinical Outcomes in Mismatch Repair Proficient/Microsatellite Stable Colorectal Cancer

The cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway plays a crucial role in activating immune cells in the tumor microenvironment, thereby contributing to a more favorable response to immune checkpoint inhibitors (ICI) in colorectal cancer (CRC). However, the impact of the expression of cGAS-STING in tumor cells on the infiltration of CD8⁺ T cells and clinical outcomes in mismatch repair proficient/microsatellite stable (pMMR/MSS) CRC remains largely unknown. Our findings reveal that 56.8% of all pMMR CRC cases were cGAS-negative/STING-negative expressions (cGAS^-/STING^-) in tumor cells, whereas only 9.9% of all pMMR CRC showed cGAS-positive/STING-positive expression (cGAS⁺/STING⁺) in tumor cells. The frequency of cGAS⁺/STING⁺ cases was reduced in the advanced stages of pMMR/MSS CRC, and histone methylation might be involved in the down-regulation of STING expression in tumor cells. Since the expression level of cGAS-STING in tumor cells has been associated with the infiltration of CD8⁺ and/or CD4⁺ T cells and the frequency of recurrence in pMMR/MSS CRC, decreased expression of cGAS-STING in tumor cells might lead to poor immune cell infiltration and worse prognosis in most pMMR/MSS CRC patients. Our current findings provide a novel insight for the treatment of patients with pMMR/MSS CRC.

Radiation-Induced Remodeling of the Tumor Microenvironment Through Tumor Cell-Intrinsic Expression of cGAS-STING in Esophageal Squamous Cell Carcinoma

PURPOSE

Radiation therapy (RT) has the potential to activate the tumor-microenvironment (TME) and promote the efficacy of immune checkpoint blockade therapy. Tumor cell-intrinsic expression of cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) plays an important role in regulations of radiation-induced activation of immune cells in the TME. However, the role of tumor cell-intrinsic cGAS-STING in radiation-mediated remodeling of the TME in esophageal squamous cell carcinoma (ESCC) is not completely understood; thus, we investigated its effect on the radiation-mediated remodeling of the TME in ESCC.

METHODS

We assessed the effect of tumor cell-intrinsic cGAS-STING on the expression of mediators of the immune system, including type I interferon, T-cell chemo-attractants, colony-stimulating factor-1, and interleukin 34 (IL-34), induced by radiation in ESCC cell lines. We also quantified the association between tumor cell-intrinsic expression of cGAS-STING and infiltrations of immune cells, including CD8⁺ T cells and CD163⁺ M2-tumor-associated macrophages (TAMs), in ESCC tissues before and after neoadjuvant chemo-RT (n = 47).

RESULTS

We found that tumor cell-intrinsic expression of cGAS-STING was involved in radiation-induced infiltration of CD8⁺ T cells and expression of type I interferon and T-cell chemo-attractants in ESCC cells. Surprisingly, tumor cell-intrinsic cGAS-STING was also involved in radiation-triggered infiltration and/or M2-polarization of CD163⁺ TAMs and expression of IL-34, an important cytokine for recruitment and M2-polarization of TAMs, in ESCC cells. The number of CD163⁺ M2-TAMs was significantly associated with IL-34 expression in tumor cells in irradiated ESCC tissues.

CONCLUSIONS

The tumor cell-intrinsic expression of cGAS-STING is essential for radiation-induced activation of immune cells in the TME, but it is also involved in the recruitment of tumor-promoting M2-TAMs in ESCC. Therefore, blocking of M2-TAM infiltration by targeting IL-34 might improve the efficacy of RT and combination therapy of RT with immune checkpoint inhibitors in ESCC.

Systemic inflammation score as a preoperative prognostic factor for patients with pT2-T4 resectable gastric cancer: a retrospective study

BACKGROUND

Systemic inflammation has been reported to be associated with cancer progression and metastasis. Systemic inflammation score (SIS), calculated from preoperative serum albumin level and lymphocyte-to-monocyte ratio, has been shown to be a novel prognostic factor for several types of tumors. This study aimed to evaluate the prognostic value of the SIS in patients with pT2-4 resectable gastric cancer (GC).

METHODS

Total 97 patients with pT2-4 GC who underwent curative surgery from 322 cases between 2009 and 2015 in Fukushima Medical University Hospital were included. We performed univariate and multivariate analyses to evaluate the usefulness of preoperative SIS and other prognostic factors for relapse-free survival (RFS) and overall survival (OS).

RESULTS

The higher SIS score was associated with undifferentiated cancer and recurrence. Univariate analysis of RFS identified deeper tumor invasion and higher SIS were significant risk factors and multivariate analysis revealed that both of them were independent prognostic factors for RFS. As for OS, age, tumor invasion, SIS and LNR were significantly correlated with RFS. In multivariate analysis, tumor invasion, SIS and LNR were independent prognostic factors for OS.

CONCLUSIONS

SIS was an independent prognostic factor for RFS and OS in pT2-4 resectable gastric cancer patients who underwent curative gastrectomy.

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-β 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.

Short-term outcomes of neoadjuvant chemotherapy with capecitabineplus oxaliplatin for patients with locally advanced rectal cancerfollowed by total or tumor-specific mesorectal excision with orwithout lateral pelvic lymph node dissection

Background: The standard strategy in Japan for locally advanced rectal cancer is total mesorectal excision plus adjuvant chemotherapy. However, large tumors significantly restrict pelvic manipulation of the distal side of the tumor during surgery; therefore, from an oncological point of view, it is better to shrink the tumor as much as possible preoperatively to optimize the circumferential resection margin. In recent years, advances in systemic chemotherapy have significantly improved the tumor reduction effect, enabling such drug therapy prior to surgery for locally advanced rectal cancer. We herein retrospectively evaluated the clinical, short-term outcomes of patients treated by neoadjuvant chemotherapy (NAC) using capecitabin and oxaliplatin (CAPOX), focusing on overall safety as well as clinical and pathological staging responses to NAC.

Methods: We applied the preoperative chemotherapy protocol to T3-4, any N, M0 or M1a (with resectable metastases) (UICC 8^th) Ra/Rb rectal cancers. The chemotherapy regimen consisted of four cycles of CAPOX. After NAC, curative intent surgery with total mesorectal excision/tumor-specific mesorectal excision with/without metastasectomy was performed. Adverse effects (AEs) and compliance with NAC, surgical complications, clinical and pathological staging were evaluated. All patients undergoing the protocol between January 2017 and June 2021 at Fukushima Medical University were enrolled.

Results: Twenty cases were enrolled. No severe AEs were observed either preoperatively or perioperatively. Preoperative assessment of NAC showed no cases of progressive disease (PD). Radical resection was achieved in all cases. Histological therapeutic grading after NAC revealed one grade 3, four grade 2, three grade 1b, eleven grade 1a and one grade 0 among all cases.

Conclusion: This study suggests that NAC for locally advanced rectal cancer is likely to be acceptable because there were no severe AEs pre- or perioperatively, radical resection was achieved in all cases, and there were no cases of PD.

Clinical outcomes of laparoscopic and endoscopic cooperative surgery for gastric gastrointestinal stromal tumor

BACKGROUND

Laparoscopic and endoscopic cooperative surgery (LECS) is a well-recognized surgical procedure for gastric gastrointestinal stromal tumor (GIST). In this report, we describe the clinical outcomes of LECS procedures for gastric GIST in our institution.

METHODS

We performed LECS procedures, including classical LECS, inverted LECS, closed LECS, and combination of laparoscopic and endoscopic approaches to neoplasia with non-exposure technique (CLEAN-NET), in 40 gastric intraluminal and intramural type GIST patients, whose tumors were ≤ 50 mm in diameter, between September 2012 and December 2020. The patient background, surgical outcomes, postoperative morbidity and mortality, as well as the tumors' clinicopathological characteristics were analyzed retrospectively.

RESULTS

Pathological findings showed that most patients had a low or very low risk of tumor recurrence, while one patient had a high risk according to the modified-Fletcher's classification. The median length of postoperative hospital stay was 7 days. Only one patient had severe postoperative grade III complications according to the Clavien-Dindo (C-D) classification, after closed LECS, but was treated successfully with endoscopic hemostasis for postoperative hemorrhage. The remaining patients treated with LECS did not have severe complications. During the follow-up period (median, 31 months), all patients were disease-free, with no tumor recurrence or metastases.

CONCLUSION

LECS is a safe surgical procedure for gastric intraluminal and intramural type GIST ≤ 50 mm in diameter, with good clinical outcomes.

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.

[Significance and Treatment Strategy of Glasgow Prognostic Score in High Risk Stage Ⅱ 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.

Exploration of electrocardiographic and echocardiographic findings to screen transthyretin amyloid cardiomyopathy in patients with mild left ventricular hypertrophy

Background

The transthyretin amyloid cardiomyopathy (ATTR-CM), a common condition in the elderly, is a life-threatening disease; however, it is treatable. The early accurate diagnosis is, therefore, an important key to improve the patient's outcomes. Electrocardiography and echocardiography are instant diagnostic tools with red flags for the screening of the ATTR-CM. In fact, ATTR-CM often mimics left ventricular hypertrophy (LVH), and the differential diagnosis is difficult to establish. Thus, the characteristics of cardiac amyloidosis may be obscured in ATTR-CM patients with mild LVH, possibly making the disease difficult to diagnose. Therefore, in this study, the effect of LVH on the occurrence of electrocardiographic and echocardiographic parameters for ATTR-CM was investigated, and their incremental value over the age for the screening of ATTR-CM in the patients with mild LVH was recorded.

Methods

This study retrospectively studied 319 consecutive nonischemic LVH patients with a sinus rhythm who underwent detailed diagnostic tests. The light chain-associated amyloidosis was an exclusion criterion. The mean left ventricular wall thickness (MWT) &lt;12 mm was defined as mild LVH, while MWT ≥12 mm was defined as moderate to severe LVH. The ATTR-CM was diagnosed with biopsy or 99 mTc-PYP scintigraphy. The elderly were defined as people aged ≥65 years in males and ≥70 years in females, according to the literature. Each electrocardiographic and echocardiographic parameter was binarized with an external cut-off point to increase the external validity, being the incremental benefit of each parameter over age for identifying ATTR-CM assessed using a receiver operating characteristic curve analysis and comparisons of the area under the curve (AUC).

Results

Fourteen patients (8%) among the 170 patients with mild LVH had ATTR-CM, while 27 patients (18%) among the 149 patients with moderate to severe LVH had ATTR-CM. The patients with mild LVH had fewer electrocardiographic and echocardiographic parameters, showing a significant difference between ATTR-CM and non-ATTR-CM patients than those with moderate to severe LVH (Table 1). Among several binarized parameters, the voltage-to-mass ratio, E/A ratio, the global longitudinal strain, and also the relative apical sparing pattern demonstrated additive value for identifying the ATTR-CM over aging (Table 2). In addition, the discriminative ability of the propensity score calculated from these four variables and age was considered excellent for the screening of ATTR-CM (AUC = 0.98).

Conclusion

The patients with mild LVH appear to have fewer electrocardiographic and echocardiographic specific findings of the ATTR-CM compared to patients with moderate to severe LVH. However, several red flags may be useful for screening ATTR-CM even in patients with a mild LVH.

Funding Acknowledgement

Type of funding sources: None. Table 1Table 2

The Expression of Immune Checkpoint Receptors and Ligands in the Colorectal Cancer Tumor Microenvironment

BACKGROUND/AIM

The limited efficacy of immune checkpoint inhibitors in colorectal cancer (CRC) is likely due to immunosuppressive mechanisms including T cell exhaustion caused by inhibitory immune checkpoints in the tumor microenvironment.

MATERIALS AND METHODS

We investigated the expression status of the inhibitory immune checkpoint receptors on tumor-infiltrating T cells and their ligands on tumor cells by flow cytometry and immunohistochemistry, using surgically-resected specimens of CRC.

RESULTS

Flow cytometry analysis indicated that TIM-3, TIGIT, and PD-1 were expressed on tumor-infiltrating CD4+ (8.3%, 56.0%, 26.1%) and CD8+ T cells (8.2%, 51.6%, 23.5%), and CRC cells abundantly expressed PD-L1, CEACAM-1, and CD155 (2.2%, 77.0%, 46.8%). Immunohistochemical analysis revealed that the tumor proportional score of PD-L1, CEACAM-1, and CD155 was 42.4%, 54.2%, and 52.1%, respectively.

CONCLUSION

PD-1, TIM-3, and TIGIT axes may reduce T cell function in the CRC tumor microenvironment.

[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.

Validation of Gene Expression-Based Predictive Biomarkers for Response to Neoadjuvant Chemoradiotherapy in Locally Advanced Rectal Cancer

BACKGROUND

Neoadjuvant chemoradiotherapy (nCRT) followed by surgery is widely used for patients with locally advanced rectal cancer. However, response to nCRT varies substantially among patients, highlighting the need for predictive biomarkers that can distinguish non-responsive from responsive patients before nCRT. This study aimed to build novel multi-gene assays for predicting nCRT response, and to validate our signature and previously-reported signatures in multiple independent cohorts.

METHODS

Three microarray datasets of pre-therapeutic biopsies containing a total of 61 non-responders and 53 responders were used as the discovery cohorts to screen for genes that were consistently associated with nCRT response. The predictive values of signatures were tested in a meta-analysis using six independent datasets as the validation cohorts, consisted of a total of 176 non-responders and 99 responders.

RESULTS

We identified four genes, including BRCA1, GPR110, TNIK, and WDR4 in the discovery cohorts. Although our 4-gene signature and nine published signatures were evaluated, they were unable to predict nCRT response in the validation cohorts.

CONCLUSIONS

Although this is one of the largest studies addressing the validity of gene expression-based classifiers using pre-treatment biopsies from patients with rectal cancer, our findings do not support their clinically meaningful values to be predictive of nCRT response.

[A Case of Laparoscopic Surgery for Preoperatively Diagnosed Gastric Metastasis of Lung Cancer]

The patient was a 66-year-old male who had undergone an operation for lung cancer and solitary brain metastases. Follow- up PET-CT after 1 year detected FDG accumulation in the stomach. We performed esophagogastroscopy and found an approximately 20 mm-sized Type 2 tumor on the greater curvature of the upper stomach. A pathological diagnosis of lung adenocarcinoma metastasis in the stomach was made. Laparoscopic surgery was performed on the metastatic lesion to prevent bleeding and perforation, and resection was achieved with minimal invasion. The current development of chemotherapy, including immunotherapy, has contributed to the improved prognosis of cancer patients, including those with lung metastasis in the stomach. Considering these backgrounds, preventive surgical resection under laparoscopy may be an effective approach for improving prognosis and preventing acute life-threatening adverse events. We report this case along with a literature review.

Circulating tumor cells after neoadjuvant chemotherapy are related with recurrence in esophageal squamous cell carcinoma

BACKGROUND

Circulating tumor cells (CTCs) are known to be a systemic process of malignant progression of cancer cells and there is a possibility that analysis for CTCs as a liquid biopsy become predictive or prognostic tools for cancer patients.

METHODS

In the present study with the novel CTCs detection system (Celsee system^®), we performed quantitative and qualitative analysis of CTCs in patients with esophageal squamous cell carcinoma (ESCC) receiving neoadjuvant chemotherapy (NAC) with 5FU + CDDP regimen. CTCs are defined as having both DAPI positive and CD45 negative. Vimentin-positive CTCs were defined as mesenchymal-type CTCs (M-CTCs), while epithelial-type CTCs (E-CTCs) were only positive for pan-cytokeratin.

RESULTS

At the baseline, there are detectable amounts of CTCs in all patients (n = 30) at all stages, and there were no significant differences of total CTCs, E-CTCs, or M-CTCs numbers between stages. Of importance, among total CTCs, M-CTCs are more dominant than E-CTCs in number. Also, there was no significant change of detectable amounts and phenotype of CTCs before and after NAC (n = 24). Of note, early recurrent group indicated that there was an elevated total CTCs number before NAC and an increased M-CTCs after NAC in comparison to those in non-recurrent group.

CONCLUSIONS

Quantitative and qualitative analysis of CTCs may provide useful complementary predictive and prognostic information in ESCC.

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.

Long-term Outcomes of Lower Rectal Cancer Patients Treated with Total Mesorectal Excision and Lateral Pelvic Lymph Node Dissection after Preoperative Radiotherapy or Chemoradiotherapy

Objectives:

The standard strategy for advanced rectal cancer (RC) is preoperative short-course radiotherapy (SCRT)/chemoradiotherapy (CRT) plus total mesorectal excision (TME) in Western countries; however, the survival benefit of adding chemotherapy to radiotherapy remains unclear. There is accumulating evidence that either SCRT/CRT or lateral pelvic lymph node dissection (LPND) alone may not be sufficient for local control of advanced RC. We herein retrospectively evaluated the clinical outcomes of patients who were treated by SCRT/CRT+TME+LPND, particularly focusing on the prognostic impact of lateral pelvic lymph node metastasis (LPNM).

Methods:

Patients diagnosed as having clinical Stage II and III lower RC who received SCRT/CRT+TME+LPND between 1999 and 2012 at our hospital were enrolled. Adverse events (AEs), surgery-related complications (SRC), and therapeutic effects were retrospectively analyzed.

Results:

Fifty cases (SCRT:25, CRT:25) were analyzed. No significant differences were observed in overall survival (OS), relapse-free survival (RFS), local recurrence (LR), AE, and SRC between the SCRT and CRT groups, although the pathological therapeutic effect was higher in the CRT group. The patients with LPNM showed significantly inferior 5-year OS and 5-year RFS than those without LPNM.

Conclusions:

There were no significant differences in OS, RFS, or LR between SCRT and CRT, although CRT had a significantly greater histological therapeutic effect. The prognosis of the pathological LPNM-positive cases was significantly poorer than that of pathological LPNM-negative cases.

Stromal expression of cancer-associated fibroblast-related molecules, versican and lumican, is strongly associated with worse relapse-free and overall survival times in patients with esophageal squamous cell carcinoma

Cancer-associated fibroblasts (CAFs) in the tumor microenvironment play an essential role in the tumor progression of esophageal squamous cell carcinoma (ESCC). The present study aimed to investigate the expression of CAF-related molecules, versican, periostin and lumican, in cancer stroma, to provide prognostic stratification for patients with ESCC after surgery. A total of 106 patients with ESCC who underwent curative esophagectomy without preoperative chemotherapy or radiotherapy were enrolled. The expression of CAF-related stromal proteins, including versican, periostin and lumican, was examined using immunohistochemistry, and the prognostic value was assessed by Kaplan-Meier survival analysis, and univariate and multivariate Cox regression models. The expression of versican, periostin and lumican was found specifically in the stromal component of ESCC. Kaplan-Meier analysis demonstrated that, compared with a low expression level, a high expression level of versican, periostin or lumican in the cancer stroma was significantly associated with worse relapse-free survival (RFS) and overall survival times in patients with ESCC. The prognostic values of stromal versican and lumican remained significant in a stratified analysis of stage I patients. Moreover, univariate and multivariate analysis revealed that high stromal versican or lumican expression was an independent prognostic factor for RFS in the patients. The present study demonstrated that CAF-related molecules, including versican, periostin and lumican, were expressed in the stroma of ESCC, and that stromal expression of versican and lumican in particular may have clinical utility as a prognostic biomarker for poor RFS in postoperative patients with ESCC.

EML4-ALK induces cellular senescence in mortal normal human cells and promotes anchorage-independent growth in hTERT-transduced normal human cells

BACKGROUND

Chromosomal inversions involving anaplastic lymphoma kinase (ALK) and echinoderm microtubule associated protein like 4 (EML4) generate a fusion protein EML4-ALK in non-small cell lung cancer (NSCLC). The understanding of EML4-ALK function can be improved by a functional study using normal human cells.

METHODS

Here we for the first time conduct such study to examine the effects of EML4-ALK on cell proliferation, cellular senescence, DNA damage, gene expression profiles and transformed phenotypes.

RESULTS

The lentiviral expression of EML4-ALK in mortal, normal human fibroblasts caused, through its constitutive ALK kinase activity, an early induction of cellular senescence with accumulated DNA damage, upregulation of p16INK4A and p21WAF1, and senescence-associated β-galactosidase (SA-β-gal) activity. In contrast, when EML4-ALK was expressed in normal human fibroblasts transduced with telomerase reverse transcriptase (hTERT), which is activated in the vast majority of NSCLC, the cells showed accelerated proliferation and acquired anchorage-independent growth ability in soft-agar medium, without accumulated DNA damage, chromosome aberration, nor p53 mutation. EML4-ALK induced the phosphorylation of STAT3 in both mortal and hTERT-transduced cells, but RNA sequencing analysis suggested that the different signaling pathways contributed to the different phenotypic outcomes in these cells. While EML4-ALK also induced anchorage-independent growth in hTERT-immortalized human bronchial epithelial cells in vitro, the expression of EML4-ALK alone did not cause detectable in vivo tumorigenicity in immunodeficient mice.

CONCLUSIONS

Our data indicate that the expression of hTERT is critical for EML4-ALK to manifest its in vitro transforming activity in human cells. This study provides the isogenic pairs of human cells with and without EML4-ALK expression.

Neoadjuvant Chemotherapy Induces IL34 Signaling and Promotes Chemoresistance via Tumor-Associated Macrophage Polarization in Esophageal Squamous Cell Carcinoma

The tumor microenvironment (TME) plays a key role in the efficacy of neoadjuvant chemotherapy (NAC) in solid tumors including esophageal squamous cell carcinoma (ESCC). However, the TME profile of ESCC treated with NAC is not fully understood. In this study, we investigated the effect of NAC on the TME especially tumor-associated macrophages (TAM), the important immunosuppressive components of the TME, in ESCC. We quantified the expression of CD163, a crucial marker of TAM, in pretherapeutic biopsy and surgically resected ESCC specimens from patients who received NAC (n = 33) or did not receive NAC (n = 12). We found that NAC dramatically increased the expression of CD163 on TAMs in ESCC. Colony-stimulating factor 1 (CSF-1) and IL34 are crucial cytokines that recruit monocytes into tumor sites and differentiate them into TAMs. Interestingly, NAC significantly upregulated the expression of IL34 but not CSF-1 on tumor cells, and the frequencies of CD163⁺ TAMs were significantly correlated with IL34 expression in ESCC after NAC. The expression of IL34 in NAC-nonresponsive patients was significantly higher than that in NAC-responsive patients, and patients with IL34-high ESCC exhibited worse prognosis as compared with patients with IL34-low ESCC. We also demonstrated that 5-fluorouracil (5-FU)/cisplatin preferentially increased mRNA expression of IL34 on human ESCC cell lines. Human peripheral blood monocytes co-cultured with ESCC cells treated with 5-FU/cisplatin increased the expression of CD163, which was attenuated by the treatment with CSF-1R inhibitors. These data suggest that IL34 expression by NAC shifts the TME toward CD163⁺ TAM-rich immunosuppressive and chemo-insensitive microenvironment in ESCC. IMPLICATIONS: The blockade of IL34 signaling may offer a novel therapeutic strategy against chemoresistance in ESCC by inhibiting M2-TAM polarization.

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.

[A Case of Pelvic Liposarcoma Resected by Hybrid Approach]

Surgical resection is the most effective treatment for liposarcoma, a retroperitoneal malignant soft tissue tumor, and a reliable negative margin is required because of the high risk of local recurrence. We reported a case of pelvic liposarcoma that could be resected by laparoscopic and transsacral hybrid approach. A 60's-man had a mixed liposarcoma occupying the right rear of the pelvis in the rectum. The operation was preceded by a laparoscopic operation, and the right internal iliac artery and vein and the superior rectal artery were dissected. The tumor was separated along the right pelvic wall. The oral rectum was transected and the colon was elevated by the extraperitoneal route. After conversion to the Jackknife position, the anterior sacrum was exfoliated with the right transsacral approach, the coccyx was resected, and the rectal anus, tumor, and surrounding fatty tissue were removed as an en bloc fasion. Histopathological examination showed mixed type of liposarcoma and negative margin of the stump. The patient is alive without recurrence 8 months after the surgery.

Tn Antigen Expression Defines an Immune Cold Subset of Mismatch-Repair Deficient Colorectal Cancer

Colorectal cancer (CRC) cells often express Tn antigen, a tumor-associated truncated immature O-glycan (GalNAcα-O-Ser/Thr) that can promote tumor progression. Immunotherapies against Tn antigen have been developed and are being evaluated in clinical trials. Tn antigen can also be considered a novel immune checkpoint that induces immunosuppressive signaling through glycan-biding lectins to lead effector T cell apoptosis. We evaluated the correlation of Tn antigen expression by immunohistochemistry with mismatch-repair (MMR) status, tumor-infiltrating lymphocytes, tumor cell PD-L1 expression, and clinicopathological characteristics in 507 CRC patients. Although 91.9% of CRCs showed negative or weak Tn antigen staining (Tn-negative/weak), we identified a small subset of CRCs (8.1%) that displayed particularly intense and diffuse distribution of Tn antigen immunoreactivity (Tn-strong) that closely related to deficient MMR (dMMR). Moreover, 40 dMMR CRCs were stratified into 24 Tn-negative/weak dMMR tumors (60.0%) exhibiting dense CD8+ lymphocyte infiltrate concomitant with a high rate of PD-L1 positivity, and 16 Tn-strong dMMR tumors (40.0%) that demonstrated CD8+ T cell exclusion and a lack of PD-L1 expression, which was comparable to those of proficient MMR. Our finding suggests that the immune cold subset of patients with Tn-strong dMMR CRC may be effectively treated with immune checkpoint blockade therapy or cellular immunotherapy targeting Tn antigen.

Clinical significance of the relative apical sparing pattern of longitudinal strain in patients with cardiac amyloidosis

Background

The relative apical sparing pattern (RASP) of left ventricular (LV) longitudinal strain (LS) is frequently associated with cardiac amyloidosis (CA). However, some patients with CA do not show the RASP, and their clinical characteristics have not been fully clarified. We sought to investigate the clinical significance of RASP in patients with CA.

Methods

One hundred consecutive CA patients who were diagnosed by biopsy or myocardial pyrophosphate scintigraphy and evaluated for RASP (mean age: 76 years, male: 77%, LV mean wall thickness: 13.5 mm, light-chain [AL] type: 33 cases, transthyretin [TTR] type: 67 cases) were retrospectively enrolled. The RASP was semi-quantitatively and quantitatively assessed. Semi-quantitative RASP was defined as reduction of LS (≥−10%) in ≥5 (of 6) basal segments relative to preserved LS (&lt;−15%) in ≥1 apical segment. Quantitative RASP was calculated according to the following formula: Quantitative RASP = [Average apical LS] / [Average basal LS + Average mid LS]. We adapted three validated thresholds (&gt;1.00, &gt;0.90, and &gt;0.87) according to the literature.

Results

Semi-quantitative and binalized quantitative RASP (&gt;1.00, &gt;0.90, and &gt;0.87) were observed in 55, 55, 63, and 65 patients, respectively. RASP in each definition was more prevalent in the TTR group than in the AL group. Additionally, RASP was significantly associated with higher LV wall thickness even after adjustment for the CA subtypes (all, p&lt;0.05, Figure). After the RASP assessment, 35 all-cause deaths and 26 cardiac deaths were observed during the follow-up period (median, 1.1 years). Although these events were significantly associated with poor nutrition, lower blood pressure, higher New York Heart Association class, and the AL group, no association was found with RASP and LV wall thickness.

Conclusions

The incidence of RASP is low in the case of thin LV wall thickness in CA patients, which may indicate the difficulty of early diagnosis of CA using RASP in patients with mild LV hypertrophy. The prognostic prediction using RASP may be challenging in this cohort.

Figure 1

Funding Acknowledgement

Type of funding source: None

Utility of scoring system including relative apical sparing pattern for screening cardiac amyloidosis in patients with left ventricular hypertrophy

Background

Cardiac amyloidosis (CA) is an infiltrative disease mimicking left ventricular hypertrophy (LVH), although its prognosis is poorer than other diseases with LVH. Moreover, because CA is treatable, appropriate screening for CA is an important area of study for clinicians to prevent and treat the disease. Several imaging predictors of CA have been reported so far;. in particular, deformation parameters such as relative apical sparing patterns of longitudinal strain (RASP) may diagnose CA with better precision than conventional parameters. Accordingly, we hypothesized that the inclusion of deformation parameters into the established diagnostic parameters would permit derivation of a risk score for CA screening in patients with LVH. Thus, we aimed to 1) investigate the incremental benefits of deformation parameters over established diagnostic parameters for CA screening in patients with LVH; 2) determine the risk score to screen CA patients with LVH using all of these variables; and 3) externally validate the score.

Methods

We retrospectively studied 295 consecutive non-ischemic patients with LVH who underwent echocardiography as well as the detailed work-up for LVH (biopsy, technetium pyrophosphate scintigraphy (99mTc-PYP) or cardiac magnetic resonance imaging) (median age, 67 years; MWT, 12 mm). CA was diagnosed by biopsy or 99mTc-PYP. The base model consisted of age (≥65 [male], ≥70 [female]), low voltage in electrocardiography, and posterior wall thickness ≥14 mm in reference to previous studies. Continuous echocardiographic variables were binarized by the use of generally accepted external cutoff points to avoid best clinical scenario. Incremental benefits were assessed using receiver operating characteristic curve analysis and area under the curve (AUC) comparison. Multiple logistic regression analysis was performed to determine the risk score. The score was then validated in the external validation sample (N=178, median age, 70 years; MWT, 12 mm).

Results

CA was observed in 54 patients (18%) and of the several echocardiographic parameters studied, only RASP demonstrated a significant incremental benefit for the screening of CA over the base model (Figure A). After multiple logistic regression analysis in the prediction of CA with 4 variables (RASP and basal model components), each was assigned a numeric value based on its relative effect (Figure B). The incidence rate of CA clearly increased as the sum of the risk score increased (Figure C). The score had good discrimination ability, with an AUC of 0.87, a total score of ≥2 with 70% sensitivity and 90% specificity. Similarly, the discrimination ability of the score in the validation cohort was sufficient (AUC = 0.87).

Conclusion

Overall, we determined a simple risk score including RASP to screen CA. This score takes into account 4 common parameters used in daily practice, and therefore, has potential utility in risk stratification and management of patients with LVH.

Figure 1

Funding Acknowledgement

Type of funding source: Private hospital(s). Main funding source(s): Kitaishikai

Incremental benefits of echocardiographic indices over clinical parameters for screening cardiac amyloidosis in patients with left ventricular hypertrophy

Background

Cardiac amyloidosis (CA), characterized by amyloid protein deposition in the heart, is a treatable disease. Although left ventricular (LV) wall thickness is the most established imaging predictor for CA, several echocardiographic indices including deformation parameters also contribute to the screening of CA. However, it is unclear whether additive values of echocardiographic indices have greater benefit over the conventional clinical predictors for the screening of CA. Therefore, we sought to compare the incremental benefits of echocardiographic indices over the clinical parameters for the screening of CA and externally validate their incremental benefits.

Methods

We retrospectively studied 295 consecutive patients (median age, 67 years; male, 65%; mean LV wall thickness (MWT), 12 mm) with LV hypertrophy who underwent echocardiography as well as the detailed work-up for myocardium (Biopsy, technetium pyrophosphate scintigraphy (99mTc-PYP) or cardiac magnetic resonance imaging). CA was diagnosed through biopsy or 99mTc-PYP. The clinical model considers patients' age and the low-voltage in electrocardiography in reference to previous studies. Continuous echocardiographic variables were represented in binary through generally accepted external cutoff points. The incremental benefits of the echocardiography findings over the clinical model were assessed using with the help of both receiver-operated characteristic curve analysis and comparison of area under the curves. Furthermore, these incremental benefits were validated in the external validation sample (median age, 70 years; male, 69%; MWT, 12 mm).

Results

Among the enrolled patients, CA was observed in 18% of cases. Table presents the results of this study. Of the echocardiographic parameters, relative apical sparing pattern (RASP) was the greatest contributor for improvement of diagnostic accuracy of the clinical model. The next greatest contributor was LV wall thickness, followed by left atrial reservoir strain (LAS), E/e', left atrial volume index, ejection fraction strain ratio, and pericardial effusion, respectively. Similarly, RASP, LV wall thickness, global longitudinal strain, ejection fraction, LAS, and granular sparkling showed significant incremental benefit in the validation cohort. Only mean wall thickness, LV wall thickness, LAS, E/e' and RASP consistently improved the diagnostic accuracy of the clinical model.

Conclusion

During the screening process, adding LV wall thickness, LAS, and RASP to the clinical parameters may be useful for the accurate diagnosis of CA in patients with LV hypertrophy.

Figure 1

Funding Acknowledgement

Type of funding source: None

Clinical usefulness of relative apical sparing pattern for predicting functional recovery after transcatheter aortic valve implantation in patients with severe aortic stenosis

Background

Relative apical sparing pattern (RASP) is thought to be associated with prognosis in patients with cardiac amyloidosis or left ventricular hypertrophy (LVH). Although almost all patients with severe aortic stenosis (AS) have LVH, little is known about the effect of transcatheter aortic valve implantation (TAVI) in patients with severe AS exhibiting a RASP.

Purpose

This study aimed to elucidate the effect of TAVI on left ventricular global longitudinal strain (LS; LVGLS) in patients with severe AS exhibiting a RASP.

Methods

Eighty-four patients who underwent transfemoral or subclavian TAVI were evaluated. They were divided into the RASP and non-RASP groups. The average apical LS divided by the sum of the average mid and basal LS values of &gt;1.0 was defined as the RASP. We analyzed the difference between pre- and post-TAVI LVGLS (ΔGLS = post-TAVI LVGLS − pre-TAVI LVGLS).

Results

Of the 84 patients (mean age, 84.5±3.9 years; 24 men), 15 (17.9%) exhibited a RASP. No significant difference in mean pre-TAVI LVGLS was found between the RASP and non-RASP groups (−16.6% ± 3.8% vs. −15.8% ± 3.9%). The ΔGLS in the RASP group was significantly higher than that in the non-RASP group (−0.97% ± 2.5% vs. −2.6% ± 3.0%; P&lt;0.05). Multivariate analysis revealed that relative apical longitudinal strain was an independent predictor of ΔGLS (β = 0.35, p=0.002).

Conclusion

Relative apical longitudinal strain was associated with LVGLS recovery. The effect of TAVI on LVGLS in patients with a RASP is inferior to that in patients without a RASP.

Funding Acknowledgement

Type of funding source: None

Immune suppression caused by PD-L2 expression on tumor cells in gastric cancer

BACKGROUND

Gastric cancer (GC) patients with PD-L1-negative tumor occasionally have a favorable response to anti-PD-1 mAb. The aim of the present study was to investigate the regulatory mechanism and immunosuppressive role of PD-L2 in GC.

METHODS

We used immunohistochemistry to evaluate the expression of PD-L2 in primary tumors from 194 patients with GC. The mechanism of PD-L2 expression was assessed in TCGA stomach adenocarcinoma tissue dataset and in vitro assay using GC cell lines. The immunosuppressive role of PD-L2 was evaluated by cytotoxicity of CTL clone against PD-L2 expressing GC cells.

RESULTS

PD-L2 was expressed on tumor cells (TCs) of 28.4% patients and PD-L2 expression on TCs was significantly associated with tumor progression. TCGA dataset revealed that IFN-γ and, to a lesser extent, IL-4 signature significantly correlated with PD-L2 expression. In vitro assay showed that IFN-γ and, also to a lesser extent, IL-4 can upregulate PD-L2 expression on GC cells. Anti-PD-L2 mAb significantly enhanced the cytotoxicity of CTL clone against GC cell lines expressing PD-L2.

CONCLUSIONS

PD-L2 is expressed on GC cells and PD-1/PD-L2 interaction are functionally involved in anti-tumor CTL activities. PD-L2 expression should be considered when determining the optimal immunotherapy for GC.

KRT17 as a prognostic biomarker for stage II colorectal cancer

Adjuvant chemotherapy is considered for patients with stage II colorectal cancer (CRC) characterized by poor prognostic clinicopathological features; however, current stratification algorithms remain inadequate for identifying high-risk patients. To develop prognostic assays, we conducted a step-wise screening and validation strategy using nine cohorts of stage II patients based on multiple platforms, including microarray, RNA-sequencing (RNA-seq) and immunohistochemistry (IHC) on formalin-fixed paraffin-embedded (FFPE) tissues. Four microarray datasets (total n = 458) were used as the discovery set to screen for single genes associated with postoperative recurrence. Prognostic values of candidate genes were evaluated in three independent microarray/RNA-seq validation cohorts (n = 89, n = 93 and n = 183, respectively), and then IHC for KRT17 was conducted in two independent FFPE series (n = 110 and n = 44, respectively). We found that high levels of KRT17 transcript expression were significantly associated with poor relapse-free survival (RFS) not only in the discovery set, but also in three validation cohorts, and its prognostic impact was independent of conventional factors by multivariate analyses. Positive staining of KRT17 protein was significantly associated with poor RFS in two independent FFPE cohorts. KRT17 protein expression had independent prognostic impact on RFS in a multivariate model adjusted for conventional variables, including high-risk clinicopathological features. In conclusion, using nine independent cohorts consisting of 997 stage II patients, we identified and validated the expression of KRT17 transcript and KRT17 protein as a robust prognostic biomarker that can discriminate postoperative stage II patients who are at high probability of disease recurrence, providing additional prognostic stratification beyond the currently available high-risk factors.

A TGFβ-Dependent Stromal Subset Underlies Immune Checkpoint Inhibitor Efficacy in DNA Mismatch Repair-Deficient/Microsatellite Instability-High Colorectal Cancer

Patients with DNA mismatch repair-deficient (dMMR)/microsatellite instability-high (MSI-H) colorectal cancer represent a biomarker-defined population with distinct clinicopathologic features who are susceptible to immune checkpoint inhibitors (ICI). However, their survival outcomes vary considerably and nearly half of them exhibit primary resistance to current ICIs, suggesting substantial molecular heterogeneity even among tumors with dMMR/MSI-H. We conducted an extensive analysis of the tumor microenvironment (TME) using multiple transcriptomic, proteomic, and IHC cohorts of colorectal cancer, comprising 222 dMMR/MSI-H and 1440 MMR-proficient/microsatellite stable tumors. We developed a TGFβ-responsive stromal gene signature and then identified a unique poor prognostic subgroup of patients with dMMR/MSI-H colorectal cancers, characterized by the upregulation of transcriptional programs, including the TGFβ-rich active TME, angiogenesis, M2 macrophage polarization, and the extracellular matrix signature predictive of ICI resistance. The TGFβ-dependent stromal subset within dMMR/MSI-H tumors exhibiting poor survival outcomes was further recapitulated by proteomic datasets and IHC for VCAN protein expressed by cancer-associated fibroblasts. Meanwhile, this dMMR/MSI-H stromal subgroup was enriched neither with CD8⁺ T-cell infiltration nor common genomic alterations, such as mutation density and BRAF mutations, compared with dMMR/MSI-H tumors without TGFβ-dependent stromal activation. In conclusion, this study revealed a novel stromal subgroup of patients with dMMR/MSI-H colorectal cancer, demonstrating a TGFβ-rich tumor-promoting TME and unfavorable survival outcomes. IMPLICATIONS: Dual inhibition of immune checkpoints and TGFβ signaling may offer a promising strategy for these patients.

Higher modified Glasgow Prognostic Score and multiple stapler firings for rectal transection are risk factors for anastomotic leakage after low anterior resection in rectal cancer

OBJECTIVE

Anastomotic leakage (AL) is one of the most devastating complications of rectal cancer surgery. Not only does AL result in reduced quality of life, extended hospitalization and impaired defecatory function, it also has a high local recurrence rate. In this study, we investigated risk factors for AL as it may help to decrease its occurrence and improve patient outcomes.

METHODS

This study was a retrospective, single-institution study of rectal cancer patients who underwent elective low anterior resection between April 2002 and February 2018 at Fukushima Medical University Hospital. Patients were divided into two groups according to the presence of AL. Patient-, tumor-, and surgery-related variables were examined using univariate and multivariate analyses.

RESULTS

One hundred sixty-one patients, average age 63.5±11.5 years, were enrolled in the study. The overall AL rate was 6.8% (11/161). In the univariate analysis, modified Glasgow Prognostic Score (mGPS)=2 (p=0.003), use of multiple staplers (≥3 firings) for rectal transection (p=0.001) and intraoperative bleeding (≥250 g) were significantly associated with AL incidence. Multivariate analysis identified that mGPS = 2 (odds ratio [OR]: 19.6, 95% confidence interval [CI]: 2.96-125.00, p=0.002) and multiple firings (OR: 18.19, CI: 2.31-111.11, p=0.002) were independent risk factors for AL.

CONCLUSION

Higher mGPS score and multiple firings were independent risk factors for AL.

[A Case of Rectovaginal Fistula after Rectal Cancer Surgery Cured with Estriol Vaginal Tablet and Vaginal Lavage]

Although rectovaginal fistula is a rare complication of rectal cancer surgery, it is usually difficult to cure with conservative treatment, and patients generally need surgical intervention. A woman in her 70s underwent laparoscopic low anterior resection with right lateral lymph node dissection for rectal cancer. On postoperative day(POD)6, she had an anastomotic leakage and received conservative treatment. On POD 9, she underwent emergent laparotomy for urinary peritonitis as well as ileostomy and ureteral stenting. On POD 21, the rectovaginal fistula was confirmed with lower gastrointestinal tract fluoroscopic examination. The patient received conservative therapy for the rectovaginal fistula with estriol vaginal tablets and vaginal lavage for 2 weeks. Subsequently, the fistula was completely cured. After continuation of the estriol vaginal tablets for 4 weeks, the rectovaginal fistula has not recurred at the most recent follow-up.

Microanatomy of inferior mesenteric artery sheath in colorectal cancer surgery

Objectives: Left colic artery preserving lymph node dissection around the inferior mesenteric artery (IMA) is a standard procedure for rectal cancer surgery. Although the IMA sheath is a well-known structure, to our knowledge, there are no reports describing its microanatomy from an oncological point of view; therefore, there is no consensus on how to handle the sheath for accurate lymph node dissection around IMA. We aimed to investigate the components of the IMA sheath pathologically, focusing particularly on the presence of lymph nodes (LNs) and lymphatic ducts (LDs). Methods: We evaluated rectal and sigmoid cancer specimens resected with high-tie technique in our institute in April 2017-April 2018. The specimens were collected consecutively, without any selection. In the resected specimens, the entire anatomical structure of IMA was investigated. We defined the IMA sheath as the tissues located between the surface of the IMA adventitia and collagenous layers connecting the outermost nerve fibers. The microanatomy around the IMA was examined using H&E staining, and LDs were identified using D2-40 immunohistochemistry. Results: Twenty patients were enrolled. No LNs were observed within the sheath in any of the cases. However, there were a significant number of LDs (11.08 ± 3.35) within the sheath. Conclusions: Our anatomical definition of IMA sheath was feasible and objectively possible. These microanatomical results partially support the surgical concept of left colic artery preserving lymph node dissection around the IMA. It may be difficult to remove all lymphatic ducts without removing the IMA itself.

A subset of patients with MSS/MSI-low-colorectal cancer showed increased CD8(+) TILs together with up-regulated IFN-γ

A small subset of patients with proficient mismatch repair (pMMR)/microsatellite stable (MSS)-colorectal cancer (CRC) benefit from immunotherapy with anti-programmed cell death 1 (PD-1)/programmed death ligand 1 (PD-L1) blockade. Therefore, the aim of the current study was to evaluate the immune status of patients with pMMR/microsatellite instability-low (MSI-L)/MSS-CRC and deficient MMR (dMMR)/MSI-high (MSI-H)-CRC in order to identify responders to anti-PD-1/PD-L1 inhibitors. The current study used a dataset downloaded from The Cancer Genome Atlas (TCGA) as well as 219 clinical tissue samples to investigate the infiltrating grade of cluster of differentiation (CD) 4 and CD8 tumor infiltrating lymphocytes (TILs), the expression levels of PD-L1 and PD-L2, the interferon-γ (IFN-γ) and CD8 T effector gene signatures, and the phosphorylated signal transducer and activator of transcription 1 (p-STAT1) status in patients with pMMR/MSI-L/MSS-CRC and dMMR/MSI-H-CRC. Analysis of TCGA dataset revealed that the mRNA expression levels of PD-L1 and PD-L2, the IFN-γ gene signature and the CD8 T effector gene signature were significantly upregulated in MSI-H tumors compared with MSI-L/MSS tumors. Additionally, a subpopulation of patients with upregulation of the IFN-γ and CD8 T effector gene signatures was observed in those with MSI-L/MSS-CRC. Immunohistochemical staining of the clinical samples revealed a subpopulation of patients with pMMR-CRC that were positive for PD-L1 and p-STAT1, and whom had levels of elevated CD8(+) and CD4(+) TILs infiltration similar to those observed in patients with dMMR-CRC. The results obtained in the current study suggested that a subpopulation of patients with MSI-L/MSS-CRC and pMMR-CRC with upregulated IFN-γ and CD8 T effector gene signatures may benefit from immunotherapy with antibodies against PD-1 and PD-L1.

P6005Incidence and clinical characteristics of coronary artery spasm in patients with out-of-hospital cardiac arrest

Background

Substantial cases of out-of-hospital cardiac arrest (OHCA) due to acute coronary syndrome have been recognized thus far, but there have been few reports about the aetiology of patients with OHCA without the organic heart disease. Especially, coronary artery spasm would be one of the causes of OHCA.

Purpose

This study aimed to investigate causes of OHCA without the organic heart disease and to investigate the characteristics and angiographic findings of OHCA patients with vasospastic angina (VSA).

Methods

Between January 2010 and April 2018, 920 patients with OHCA caused by probable or definite cardiovascular disease were transferred to our hospital. Return of spontaneous contraction was successfully achieved in 151 patients, among whom diagnosis was made in 130 patients. First, we analysed the causes of OHCA in these patients. Second, we compared clinical and angiographic characteristics between the VSA group with OHCA (OHCA-VSA) and the VSA group without OHCA (stable VSA; n=72) from our database.

Results

Among the 130 patients, 95 (73%) had the organic heart disease; 72, acute coronary syndrome; 19, myocardial disease; 2, valvular heart disease; and 1, congenital heart disease. There were 35 patients (27%) without the organic heart disease. Nineteen patients had primary (i.e., Brugada syndrome, QT prolongation) or secondary arrhythmia (i.e. drug adverse effect). Electrocardiogram, coronary angiogram, and LV structure and function were normal in 35 patients. However, there were 16 patients (11%) with VSA defined by Japanese guideline. The OHCA-VSA group was significantly younger (50±14) than the stable VSA group (64±11, P=0.003). The incidence of diffuse-type spasm in the OHCA-VSA group (100%) was significantly higher than that in the stable VSA group (100% vs. 69%, P<0.05). In addition, the incidence of triple-vessel coronary spasm in the OHCA-VSA group was significantly higher than that in the stable VSA group (86% vs. 25%, P=0.003).

Conclusion

OHCA patients without the organic heart disease had considerable cases of VSA, in addition to primary or secondary arrhythmia. Furthermore, the severity of spasm in the OHCA-VSA group was more serious and extensive than in comparison with the stable VSA group.

Correlation of inflammation-related markers with MDSC and IL-17, and use as prognostic indicators in patients with advanced gastric and colorectal cancers

e14204

Background: Although a causal relationship for inflammation and immunity of cancer is more widely accepted today, the precise cell mechanisms mediating this relationship have not been elucidated. Accumulating evidence suggests that myeloid-derived suppressor cells (MDSC), may contribute to the negative regulation of immune responses during cancer and inflammation. IL-17 is a pro-inflammatory cytokine that is primarily secreted by T helper (Th)17 cells and we have reported that IL-17 correlates with immunosuppressive conditions in patients with cancer. Methods: PBMC (peripheral blood mononuclear cells) were harvested from 106 patients including 43 with gastric and 63 with colorectal cancer. PBMC were stimulated with PHA (phytohemagglutinin) and the production of IL-17 was measured by ELISA. MDSC were detected by flow cytometry (CD11b+,CD14-,CD33+). The levels of CRP (C-reacting protein) and NLR (neutrophil to lymphocyte ratio) were used as inflammatory markers. Results: Both of MDSC and IL-17 production were increased in patients with advanced stages, and correlated with each other, inflammatory markers and immune suppression. The patients were divided with average levels of MDSC and IL-17 production and the prognosis were analyzed with Kaplan-Meier method. The overall survival of patients with high MDSC or high IL-17 production were significantly worse than those with low MDSC or low IL-17 production, respectively, in patients with stages III and IV, although the differences were not significant in patients with stages I and II. Conclusions: Thus these inflammatory markers are closely related with systemic inflammation involving IL-17 and with immunosuppression driven by MDSC, and are effective prognostic indicators in patients with stages III and IV gastric and colorectal cancer.

Phospho‑STAT1 expression as a potential biomarker for anti‑PD‑1/anti‑PD‑L1 immunotherapy for breast cancer

In the present study, we evaluated the mechanisms of programmed death ligand 1 (PD-L1) expression in the breast cancer microenvironment, focusing on the role of interferon-γ (IFN-γ), and the clinical indications for anti-programmed cell death 1 (PD-1) /anti-PD-L1 immunotherapy. We evaluated PD-L1 expression in 4 breast cancer cell lines in the presence of 3 types of inhibitors, as well as IFN-γ. The expression of phosphorylated signal transducer and activator of transcription 1 (p-STAT1), one of the IFN-γ signaling pathway molecules, was analyzed using immunohistochemistry (IHC) in relation to PD-L1 and human leukocyte antigen (HLA) class I expression on cancer cells and tumor-infiltrating CD8-positive T cells in 111 patients with stage II/III breast cancer. Using The Cancer Genome Atlas (TCGA) database, the correlation of the IFN-γ signature with PD-L1 expression was analyzed in breast invasive carcinoma tissues. As a result, the JAK/STAT pathway via IFN-γ was mainly involved in PD-L1 expression in the cell lines examined. IHC analysis revealed that the PD-L1 and HLA class I expression levels were significantly upregulated in the p-STAT1-positive cases. TCGA analysis indicated that the PD-L1 expression and IFN-γ signature exhibited a positive correlation. On the whole, these findings suggest that PD-L1 and HLA class I are co-expressed in p-STAT1-positive breast cancer cells induced by IFN-γ secreted from tumor infiltrating immune cells, and that p-STAT1 expression may be a potential biomarker for patient selection for immunotherapy with anti-PD-1/anti-PD-L1 monoclonal antibodies.

miRNA-148a-3p Regulates Immunosuppression in DNA Mismatch Repair-Deficient Colorectal Cancer by Targeting PD-L1

Immunotherapy against the interaction between programmed cell death 1/programmed cell death ligand 1 (PD-L1) has emerged as a promising strategy for colorectal cancer with mismatch repair deficiency (dMMR) or microsatellite instability-high (MSI-H). The study aimed to identify miRNAs that posttranscriptionally control PD-L1 expression on tumor cells and also regulate immune evasion. A comprehensive miRNA screening using The Cancer Genome Atlas (TCGA) dataset (n = 260) combined with eight different miRNA target prediction programs resulted in the identification of a tumor suppressive miRNA, miR-148a-3p, as a potential negative regulator of PD-L1 expression, particularly in dMMR/MSI-H colorectal cancer. Using multiple cohorts of colorectal cancer, including TCGA data, a microarray dataset (n = 148), and formalin-fixed, paraffin-embedded samples (n = 395), we found that the expression of miR-148a-3p was decreased in dMMR/MSI-H tumors, correlating inversely with PD-L1 levels. We demonstrate that miR-148a-3p directly binds to the 3'-untranslated region of PD-L1, thereby reducing whole-cell and cell surface PD-L1 levels in HCT116 and SW837 cell lines. Overexpression of miR-148a-3p repressed IFNγ-induced PD-L1 expression on tumor cells and consequently diminished T-cell apoptosis in a coculture model of IL2-activated T cells and IFNγ-treated tumor cells. In conclusion, our data support a regulatory mechanism of PD-L1 expression on tumor cells and immune suppression via miR-148a-3p downregulation in colorectal cancer. IMPLICATIONS: This study provides novel evidence that miR-148a-3p negatively regulates tumor cell PD-L1 expression and decreased levels of miR-148a-3p contributes to the immunosuppressive tumor microenvironment.

[A Case of Esophageal Cancer with Cervical Lymph Node Recurrence Six Years after Complete Response to Definitive Chemoradiotherapy]

Neoadjuvant chemotherapy plus surgery is recommended for clinical StageⅡ and Ⅲ esophageal cancer treatment by the JCOG9906. In contrast, definitive chemoradiotherapy(dCRT)is also a curative treatment. We encountered a case of recurrence in the cervical lymph nodes that was confirmed 6 years later, although thoracic esophageal cancer had completely disappeared following dCRT. Since there was no recurrence or metastasis in the primary lesion or other organs, we performed bilateral cervical lymph node dissection. There were 3 lymph node metastases among the dissected cervical lymph nodes pathologically. After the surgery, no relapses have occurred without the adjuvant chemotherapy.

[A Case of Rectal Colon Cancer with Paraneoplastic Cerebellar Degeneration]

A case complicated with colorectal and prostate cancers in paraneoplastic(subacute)cerebellar degeneration(PCD)is extremely rare. We report a retrospective case of rectal carcinoma with paraneoplastic cerebellar degeneration. A 79-year-old man with Parkinson's disease was unable to walk because of paralysis. Brain MRI showed cerebellar atrophy. He was admitted to our hospital for anal bleeding and was diagnosed with colon cancer. An associated diagnosis of PCD was made. After resection, his paralysis and dysarthria were resolved to the extent of beingable to walk and speak fluently. Brain MP-RAGE showed no findings suggestive of metastasis or atrophy. He was treated surgically, which resulted in a transient improvement in PCD symptoms. Per blood testing, cytokines IL-6 and IL-10 were lower postoperatively. Immunosuppressive levels of myeloid- derived suppressor cells(MDSCs)were lower compared with the preoperative values. Thus, innate immunocompetence and resolution of paralysis followed the surgical intervention.

Glycosyltransferase Gene Expression Identifies a Poor Prognostic Colorectal Cancer Subtype Associated with Mismatch Repair Deficiency and Incomplete Glycan Synthesis

Purpose: We aimed to discover glycosyltransferase gene (glycogene)-derived molecular subtypes of colorectal cancer associated with patient outcomes.Experimental Design: Transcriptomic and epigenomic datasets of nontumor, precancerous, cancerous tissues, and cell lines with somatic mutations, mismatch repair status, clinicopathologic and survival information were assembled (n = 4,223) and glycogene profiles were analyzed. IHC for a glycogene, GALNT6, was conducted in adenoma and carcinoma specimens (n = 403). The functional role and cell surface glycan profiles were further investigated by in vitro loss-of-function assays and lectin microarray analysis.Results: We initially developed and validated a 15-glycogene signature that can identify a poor-prognostic subtype, which closely related to deficient mismatch repair (dMMR) and GALNT6 downregulation. The association of decreased GALNT6 with dMMR was confirmed in multiple datasets of tumors and cell lines, and was further recapitulated by IHC, where approximately 15% tumors exhibited loss of GALNT6 protein. GALNT6 mRNA and protein was expressed in premalignant/preinvasive lesions but was subsequently downregulated in a subset of carcinomas, possibly through epigenetic silencing. Decreased GALNT6 was independently associated with poor prognosis in the IHC cohort and an additional microarray meta-cohort, by multivariate analyses, and its discriminative power of survival was particularly remarkable in stage III patients. GALNT6 silencing in SW480 cells promoted invasion, migration, chemoresistance, and increased cell surface expression of a cancer-associated truncated O-glycan, Tn-antigen.Conclusions: The 15-glycogene signature and the expression levels of GALNT6 mRNA and protein each serve as a novel prognostic biomarker, highlighting the role of dysregulated glycogenes in cancer-associated glycan synthesis and poor prognosis. Clin Cancer Res; 24(18); 4468-81. ©2018 AACR.