[A Case of Long-Term Survival without Recurrence after Completion of Immunotherapy Due to Response of Third- Line Nivolumab for Liver Metastasis Recurrence of Esophagogastric Junction Cancer].

The patient was a 66-year-old man with dysphagia. He underwent total gastrectomy and trans-hiatal abdominal esophagectomy with lymph node dissection, including the inferior mediastinum, for esophagogastric junction cancer. The postoperative pathological examination revealed poorly differentiated adenocarcinoma T4aN2, Stage ⅢA, HER2 negative, and postoperative adjuvant therapy S-1 oral administration was started. Four months after surgery, computed tomography (CT)showed recurrent liver and para-aortic lymph node metastases. First-line XELOX therapy and second-line weekly PTX therapy resulted in PD, and nivolumab administration was started as third-line. The evaluation was PR and CR at 3 and 6 months, respectively. At the same time, he developed acute cholangitis and underwent open lithotripsy drainage. Postoperatively, treatment was terminated according to the patient's wishes. To date, it has been 5 years since the first operation and 3 and a half years since remission with nivolumab, and no recurrence has been observed. There is little evidence regarding the timing of conversion or treatment discontinuation for successful cases of immunotherapy in the salvage line for gastric cancer.

[Laparoscopic Proximal Gastrectomy with Supra-Pancreatic Dissection First Approach].

BACKGROUND: In laparoscopic proximal gastrectomy(LPG)with esophago-gastro anastomosis, the key of obtaining good surgical view is how to exclude the stomach from the supra-pancreatic area. METHODS: We could get good surgical view at the supra-pancreatic area with gastro-ptosis by firstly dissecting lesser curvature. Followed by the supra-pancreatic dissection we could efficiently dissect the gastro-splenic ligament from cranial side. We performed this procedure in 20 cases with upper gastric cancer. We evaluate the surgical outcomes of this procedure(S group)comparing to that of the previous procedure in 14 cases(G group). RESULTS: The median operative time in S group was significantly shorter than that in G group (226 min vs 249 min, p=0.02). Other data were similar in 2 groups. CONCLUSIONS: The short-term clinical outcomes of LPG with supra-pancreatic dissection first approach revealed that this technique is safe and feasible.

Soluble PD-L1 Concentration Is Proportional to the Expression of PD-L1 in Tissue and Is Associated with a Poor Prognosis in Esophageal Squamous Cell Carcinoma.

INTRODUCTION: We determined the soluble programmed cell death-1 ligand-1 (sPD-L1) concentration in patients with esophageal squamous cell carcinoma (ESCC), and confirmed the PD-L1 expression in resected specimens. METHODS: Blood samples were collected from 73 patients with histologically proven ESCC. The serum levels of sPD-L1 were measured using an enzyme-linked immunosorbent assay. The correlations between the sPD-L1 concentration and the expression of PD-L1 in tumor specimens and tumor depth, lymph node metastasis, disease stage, and various laboratory data were assessed. RESULTS: sPD-L1 levels in patients with high PD-L1 expression levels in tumor tissue were significantly higher than in patients with low PD-L1 expression levels (p = 0.042). The OS of the sPD-L1-high group was significantly worse than that of the low group (p = 0.028). Similarly, patients in whom a tissue specimen was PD-L1-positive group showed significantly poorer OS. CONCLUSION: The sPD-L1 concentration was correlated with the PD-L1 expression in tissues. Patients with PD-L1-positive tissue specimens showed significantly higher sPD-L1 levels in comparison to PD-L1-negative cases. Furthermore, patients with high sPD-L1 expression levels had a significantly worse prognosis than those with low sPD-L1 expression levels, and patients with a PD-L1-positive tissue specimen had a significantly worse prognosis than patients in whom the tissue specimen showed a low PD-L1 expression level.

Metformin-Induced Heat Shock Protein Family A Member 6 Is a Promising Biomarker of Esophageal Squamous Cell Carcinoma.

INTRODUCTION: Antidiabetic drug metformin exerts various antitumor effects on different cancers. Esophageal squamous cell carcinoma (ESCC) is an intractable digestive organ cancer and new treatment strategy is required. In this study, we performed a comprehensive gene expression analysis of ESCC cell lines treated with metformin, which provided helpful information on the antitumor effects of metformin in ESCC. Next, we selected a promising gene among them and examined its effects on ESCC properties. METHODS: We examined metformin-induced mRNA expression changes in two human ESCC cell lines by performing next-generation sequencing (NGS) and pathway analysis. Heat shock protein family A (Hsp70) member 6 (HSPA6) expression in surgical specimens obtained from 83 ESCC patients who underwent curative operations was evaluated immunohistochemically and analyzed. RESULTS: Metformin upregulated mRNA expression of the many genes, including HSPA6, a cancer immune-related gene, and inhibited mRNA expression of the other many genes. Pathway analysis indicated major canonical pathways and upstream regulators related to metformin. The result indicated HSPA6 as a promising biomarker. HSPA6 expression correlated with disease-free survival (DFS) of the patients with all stage ESCC (p = 0.021), especially with stage I/II ESCC (p < 0.001). With stage III, low HSPA6 expression was not associated with poor DFS (p = 0.918). Multivariate analysis indicated that independent low HSPA6 expression was an independent poor prognostic factor of stage I/II ESCC (p < 0.001). However, HSPA6 expression did not correlate with the clinicopathological characteristics, including age, sex, tumor depth, lymph node metastasis, tumor stage, and tumor markers of the patients with stage I/II ESCC. CONCLUSIONS: This NGS analysis detected prospective candidate genes, including HSPA6. Our results indicate that HSPA6 is a promising biomarker of the recurrence risk of stage I/II ESCC. Further studies on HSPA6 would lead to better treatment.

Tumor-derived exosomes influence the cell cycle and cell migration of human esophageal cancer cell lines.

Our laboratory previously reported the usefulness as biomarkers of exosomes in the plasma of esophageal squamous cell carcinoma (ESCC) patients. However, the influence of tumor-derived exosomes on the tumor itself and underlying mechanisms remain unclear. We here report changes in the phenotype and gene expression when cancer cells exist in an environment with tumor-derived exosomes. The exosomes were isolated from the culture medium of human ESCC cells (TE2, T.Tn) by ultracentrifugation; cell proliferation assay, wound-healing assay, and fluorescence imaging of the cell cycle were performed to clarify the phenotypic changes in the high concentration of tumor-derived exosomes. Gene expression changes were also assessed by mRNA microarray, and the data were analyzed by gene set enrichment analysis (GSEA). The data revealed that the proliferation of both TE2 and T.Tn was inhibited, and cell migration ability was upregulated in the exosome exposure group (P < .05). Fluorescence imaging using a fluorescent ubiquitination-based cell cycle indicator expressing ESCC cells revealed that the ratio of G1-phase cells was significantly increased in the exosome exposure group (P < .05). Findings of the GSEA clarified that high-density exposure of cancer-derived exosomes to their parent cancer cells downregulated the expression of genes related to cell proliferation and cell cycle, and upregulated the expression of genes related to actin filament length and extracellular structure organization. In conclusion, an environment of high-density tumor-derived exosomes induces changes in the gene expression and phenotype of tumor cells and may lead to tumor progression or malignant transformation.

[Successful Treatment of Gastric Cancer with Conversion Surgery after Nivolumab Treatment-A Case Report].

Immunocheckpoint inhibitors including anti-PD-1 antibody have shown certain therapeutic effects on various cancer types. They have also attracted great attention as novel cancer treatment options in addition to surgical resection, chemotherapy, and radiation therapy. Herein, we report a case of gastric cancer that was successfully treated with conversion surgery after nivolumab treatment. The patient was 68 years old and male. Upper gastrointestinal endoscopy revealed a type 3 tumor in the antrum, and he was referred to our department for further examination. The gastric cancer was diagnosed as cT4aN2M0, cStage ⅢA, and he was administered SOX as the first-line and nab-PTX/RAM as the second-line treatment, which was also a PD. As the third-line treatment, nivolumab showed remarkable reduction of the tumor after initiation, and after 14 courses, conversion surgery was performed. The patient remains alive without recurrence.

[Development of TP53-Targeted Treatment in Esophageal Squamous Cell Carcinoma Using Cancer Genomic Profiling Test].

Recently, the interest in cancer genomic medicine has increased, owing to the powerful and cost-effective technology of next-generation sequencing(NGS), which allows rapid identification of a large number of gene mutations. TP53 mutations are frequently found in solid cancers, especially in esophageal squamous cell carcinoma(ESCC), wherein the frequency of TP53 mutation is considered to be 90% or more. However, there is no clinical targeted therapy as yet utilizing TP53. Here, we aimed to characterize TP53 mutations associated with ESCC, in order to assess its feasibility as a therapeutic target. We extracted DNA and RNA from specimens of ESCC patients and analyzed them using NGS, which revealed different TP53 mutations. Based on previous reports, it is considered that different TP53 mutations lead to different functions of the protein, and subsequently account for varied prognosis in squamous cell carcinoma of the head and neck. We also performed cell viability assay using ESCC cell lines with different TP53 mutations and 2 kinds of p53-targeted drug and found differences in the growth inhibition of the cell lines. Although individual treatment can be determined depending on the type of TP53 mutation, it would be necessary to further examine the interaction of TP53 with other genes to determine its therapeutic efficacy as a target.

Prognostic benefit of conversion surgery for HER2 positive stage IV gastric cancer; a case series study of eleven patients treated with trastuzumab-based chemotherapy.

BACKGROUND: Since the ToGA trial, trastuzumab-based chemotherapy is the standard treatment for HER2 positive stage IV gastric cancer. However, it is not yet clear whether surgical resection after trastuzumab-based chemotherapy (conversion surgery) can improve survival of HER2 positive stage IV gastric cancer. The purpose of this study is to evaluate the prognostic benefit of conversion surgery in HER2 positive stage IV gastric cancer patients. CASE PRESENTATION: We retrospectively investigated the medical records of the patients with HER2 positive (IHC3(+) or IHC2(+)/FISH(+)) stage IV gastric cancer treated with trastuzumab-based chemotherapy as the first line treatment. Overall survival (OS) was compared between patients with conversion surgery and without. Eleven HER2 positive stage IV gastric cancer patients treated with trastuzumab-based chemotherapy as the first line treatment were evaluated. Response rate was 63.6%, and 6 of 11 patients could receive conversion surgery. R0 resection was achieved in four patients. In Kaplan-Meier analysis, patients who received conversion surgery showed significantly better OS than those without surgery (3-year survival rate, 66.7% vs. 20%, P = 0.03). The median OS of patients who achieved R0 resection is 51.8 months. CONCLUSIONS: Conversion surgery might have a survival benefit for HER2 positive stage IV gastric cancer patients. If curative surgery is technically possible, conversion surgery could be a treatment option for HER2 positive stage IV gastric cancer.

Caspase recruitment domain family member 9 expression is a promising biomarker in esophageal squamous cell carcinoma.

AIM: Esophageal squamous cell carcinoma (ESCC) is a refractory digestive organ cancer that requires better treatment strategies. We have recently reported that the antidiabetic drug metformin exerts antitumor effects on ESCC by inhibition of nuclear factor kappa B (NF-κB) nuclear translocation. In the present study, we focused on caspase recruitment domain family member 9 (CARD9), an essential signal adapter in NF-κB activation to examine whether it can be used as a prognostic factor in ESCC. METHODS: We investigated CARD9 expression immunohistochemically in clinical samples obtained from 93 patients with ESCC who underwent curative esophagectomy. CARD9 expression was analyzed for correlation with clinicopathological characteristics and ESCC prognosis. The molecular effects were investigated by knocking down ESCC cells. Comprehensive RNA expression changes in these ESCC cells were detected by next-generation sequencing (NGS). RESULTS: High CARD9 expression is significantly correlated with advanced tumor depth (P < .001), positive lymph node metastasis (P = .005) and advanced stage (P = .001). Kaplan-Meier method and the log-rank test showed that overall survival (OS) and disease-free survival (DFS) were significantly poor in the high CARD9 expression group (OS: P = .027, DFS: P = .005). Univariate and multivariate analysis showed that high CARD9 expression is a significant poor prognostic factor for DFS. Cell proliferation and migration were suppressed by CARD9 knockdown. NGS detected altered the expression of some RNAs including maternally expressed 3 (MEG3). CONCLUSION: High CARD9 expression is significantly associated with poor prognosis. Therefore, CARD9 expression may be a prospective prognostic biomarker in ESCC.

The Antitumor Effects of Metformin on Gastric Cancer In Vitro and on Peritoneal Metastasis.

BACKGROUND/AIM: Gastric cancer (GC) with peritoneal metastasis remains difficult to treat. The anti-diabetic drug metformin exerts various antitumor effects via the 5'-adenosine monophosphate-activated protein kinase (AMPK) pathway and nuclear factor-kappa B (NF-ĸB). Therefore, we evaluated the antitumor effects of metformin for GC in vitro and on peritoneal metastasis. MATERIALS AND METHODS: The human GC cell lines MKN1, MKN45, KATO-III and SNU-1 were used. The antiproliferative effect was evaluated in vitro with 0.5 mM or 25 mM glucose and in vivo using tumor xenograft peritoneal models of metastasis. The protein expression of AMPK, liver kinase B1 (LKB1) and NF-ĸB in tumors was examined by western blotting. RESULTS: Metformin inhibited cell proliferation in all GC lines and sensitivity was increased under low-glucose conditions in vitro. Metformin also suppressed peritoneal metastasis. In tumors, metformin reduced the numbers of proliferating cells and NF-ĸB expression, but a similar trend was not noted for AMPK. CONCLUSION: Metformin may be a useful drug for the treatment of GC with peritoneal metastasis.