ADAR1 is a promising risk stratification biomarker of remnant liver recurrence after hepatic metastasectomy for colorectal cancer.

Adenosine-to-inosine RNA editing is a process mediated by adenosine deaminases that act on the RNA (ADAR) gene family. It has been discovered recently as an epigenetic modification dysregulated in human cancers. However, the clinical significance of RNA editing in patients with liver metastasis from colorectal cancer (CRC) remains unclear. The current study aimed to systematically and comprehensively investigate the significance of adenosine deaminase acting on RNA 1 (ADAR1) expression status in 83 liver metastatic tissue samples collected from 36 patients with CRC. The ADAR1 expression level was significantly elevated in liver metastatic tissue samples obtained from patients with right-sided, synchronous, or RAS mutant-type CRC. ADAR1-high liver metastasis was significantly correlated with remnant liver recurrence after hepatic metastasectomy. A high ADAR1 expression was a predictive factor of remnant liver recurrence (area under the curve = 0.72). Results showed that the ADAR1 expression level could be a clinically relevant predictive indicator of remnant liver recurrence. Patients with liver metastases who have a high ADAR1 expression requires adjuvant chemotherapy after hepatic metastasectomy.

RNA Editing is a Valuable Biomarker for Predicting Carcinogenesis in Ulcerative Colitis.

BACKGROUND AND AIMS: Ulcerative colitis [UC] can lead to colitis-associated colorectal neoplasm [CAN]. Adenosine-to-inosine RNA editing, which is regulated by adenosine deaminase acting on RNA [ADAR], induces the post-transcriptional modification of critical oncogenes, including antizyme inhibitor 1 [AZIN1], leading to colorectal carcinogenesis. Therefore, we hypothesized that ADAR1 might be involved in the development of CAN in UC. METHODS: We systematically analysed a cohort of 139 UC cases [40 acute phase, 73 remission phase, 26 CAN]. The degree of inflammation was evaluated using the Mayo endoscopic score [MES]. RESULTS: The type 1 interferon [IFN]-related inflammation pathway was upregulated in the rectum of active UC, rectum of UC-CAN and tumour site of UC-CAN patients. ADAR1 expression was upregulated in the entire colon of CAN cases, while it was downregulated in non-CAN MES0 cases. ADAR1 expression in the rectum predicted the development of CAN better than p53 or ß-catenin, with an area under the curve of 0.93. The high expression of ADAR1 and high AZIN1 RNA editing in UC was triggered by type 1 IFN stimulation from UC-specific microbiomes, such as seen in Fusobacterium in vitro analyses. The induction of AZIN1 RNA editing by ADAR1, whose expression is promoted by Fusobacterium, may induce carcinogenesis in UC. CONCLUSIONS: The risk of CAN can be evaluated by assessing ADAR1 expression in the rectum of MES0 UC patients, freeing UC patients from unnecessary colonoscopy and reducing their physical burden. RNA editing may be involved in UC carcinogenesis, and may be used to facilitate the prevention and treatment of CAN in UC.

RNA editing facilitates the enhanced production of neoantigens during the simultaneous administration of oxaliplatin and radiotherapy in colorectal cancer.

Most cases of colorectal cancers (CRCs) are microsatellite stable (MSS), which frequently demonstrate lower response rates to immune checkpoint inhibitors (ICIs). RNA editing produces neoantigens by altering amino acid sequences. In this study, RNA editing was induced artificially by chemoradiation therapy (CRT) to generate neoantigens in MSS CRCs. Altogether, 543 CRC specimens were systematically analyzed, and the expression pattern of ADAR1 was investigated. In vitro and in vivo experiments were also performed. The RNA editing enzyme ADAR1 was upregulated in microsatellite instability-high CRCs, leading to their high affinity for ICIs. Although ADAR1 expression was low in MSS CRC, CRT including oxaliplatin (OX) treatment upregulated RNA editing levels by inducing ADAR1. Immunohistochemistry analyses showed the upregulation of ADAR1 in patients with CRC treated with CAPOX (capecitabine + OX) radiation therapy relative to ADAR1 expression in patients with CRC treated only by surgery (p < 0.001). Compared with other regimens, CRT with OX effectively induced RNA editing in MSS CRC cell lines (HT29 and Caco2, p < 0.001) via the induction of type 1 interferon-triggered ADAR1 expression. CRT with OX promoted the RNA editing of cyclin I, a neoantigen candidate. Neoantigens can be artificially induced by RNA editing via an OX-CRT regimen. CRT can promote proteomic diversity via RNA editing.

Impact of Amino Acids Nutrition Following Gastrectomy in Gastric Cancer Patients.

BACKGROUND/AIM: Postoperative body weight loss (BWL) and skeletal muscle loss (SML) after gastrectomy are associated with a decline in quality of life and worse longterm prognosis in gastric cancer (GC) patients. This study aimed to evaluate the efficacy of amino acids nutrition on BWL and SML in the early period following gastrectomy. PATIENTS AND METHODS: The parameters of body composition were measured by bioelectrical impedance analysis in the patients undergoing radical gastrectomy for GC and analyzed retrospectively. Patients received either peripheral parenteral nutrition (PPN) of 4.3% glucose fluid with regular diet (control group, n=43) or PPN of 7.5% glucose fluid containing amino acids plus oral nutritional supplement (ONS) rich in protein with regular diet (amino acids group, n=40) following gastrectomy. The percentages of BWL and SML from preoperative values to those at 7 days and 1 month after surgery were compared between the two groups. RESULTS: The %BWL and %SML at 7 days after surgery were significantly lower in the amino acids group than those in the control group (%BWL, -2.4±1.7% vs. -4.2±1.8%; p<0.0001, %SML, -4.1±3.8 vs. -6.5±3.8; p=0.006). Moreover, the %BWL at 1 month after surgery was significantly lower in the amino acids group compared to that in the control group (- 4.6±2.9% vs. -6.1±2.6%; p=0.01); however, the %SML was similar between the two groups. The hematological nutritional parameters were similar between the two groups. CONCLUSION: Amino acids nutrition by PPN and ONS following gastrectomy prevented postoperative BWL and SML in the early period after surgery in GC patients.

SMAD4 Germline Pathogenic Variant-Related Gastric Juvenile Polyposis with Adenocarcinoma Treated with Laparoscopic Total Gastrectomy: A Case Report.

BACKGROUND Juvenile polyposis syndrome is an uncommon, autosomal-dominant hereditary disease that is distinguished by multiple polyps in the stomach or intestinal tract. It is associated with a high risk of malignancy. Pathogenic variants in SMAD4 or BMPR1A account for 40% of all cases. CASE REPORT A 49-year-old woman underwent esophagogastroduodenoscopy because of exacerbation of anemia. She had numerous erythematous polyps in most parts of her stomach. Based on biopsy findings, juvenile polyposis syndrome (JPS) was suspected morphologically, but there was no evidence of malignancy. Colonoscopy showed stemmed hyperplastic polyps and an adenoma; video capsule endoscopy revealed no lesions in the small intestine. After preoperative surveillance, laparoscopic total gastrectomy with D1 lymph node dissection was performed to prevent malignant transformation. The pathological diagnosis was juvenile polyp-like polyposis with adenocarcinoma. In addition, a germline pathogenic variant in the SMAD4 gene was detected with genetic testing. CONCLUSIONS JPS can be diagnosed with endoscopy and genetic testing. Further, appropriate surgical management may prevent cancer-related death in patients with this condition.

Long-term survival without recurrence after surgery for gastric yolk sac tumor-like carcinoma: a case report.

BACKGROUND: Gastric yolk sac tumor (YST)-like carcinoma is extremely rare, and its prognosis is poor, because most patients have widespread metastases at the time of diagnosis. We report a case of gastric YST-like carcinoma with an adenocarcinoma component without metastases in which curative resection was performed. CASE PRESENTATION: A 77-year-old man complaining of melena and dizziness due to anemia was diagnosed with poorly differentiated adenocarcinoma in the gastric cardia, with a benign ulcer in the gastric body. He underwent total gastrectomy with D2 lymph node dissection for the tumor. Histological examination of the resected specimens revealed a mixture of reticular and glandular neoplastic components morphologically. In the reticular area, an endodermal sinus pattern and some Schiller-Duval bodies were confirmed. Gastric YST-like carcinoma with adenocarcinoma components, T2N0M0 Stage IB, was diagnosed. Immunohistochemical analysis showed that the YST was positive for carcinoembryonic antigen (CEA), alpha-fetoprotein (AFP) and p53. In contrast, the adenocarcinoma was positive for p53 and negative for CEA and AFP. The patient remained healthy as of 7 years postoperatively, with no recurrence. CONCLUSIONS: Routine medical examinations or endoscopic examinations for accidental symptom may be helpful for early diagnosis and good prognosis for gastric YST-like carcinoma, although the prognosis is generally poor.