Publications by authors named "Mitsuho Imai"

Background: The implementation of cancer precision medicine in Japan is deeply intertwined with insurance reimbursement policies and requires case-by-case reviews by Molecular Tumor Boards (MTBs), which impose considerable operational burdens on healthcare facilities. The extensive preparation and review times required by MTBs hinder their ability to efficiently assess comprehensive genomic profiling (CGP) test results. Despite attempts to optimize MTB operations, significant challenges remain.

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Background: While advanced gastrointestinal stromal tumors (GISTs) are primarily treated with tyrosine kinase inhibitors (TKIs), acquired resistance from specific mutations in KIT or PDGFRA frequently occurs. We aimed to assess the utility of circulating tumor DNA (ctDNA) as a modality of therapeutic decision-making in advanced GIST.

Methods: We conducted a pooled analysis of SCRUM-Japan studies for advanced GIST patients.

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Purpose: HER2-targeted therapies in ERBB2-amplified metastatic colorectal cancer (mCRC) are effective; however, a notable portion of patients do not respond to treatment, and secondary resistance occurs in most patients receiving these treatments. The purpose of this study was to investigate determinants of treatment efficacy and resistance in patients with ERBB2-amplified mCRC who received HER2-targeted therapy by analyzing multiomics data.

Experimental Design: We investigated genomic data from a nationwide large cancer genomic screening project, the SCRUM-Japan project.

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Article Synopsis
  • The SCRUM-Japan MONSTAR-SCREEN consortium is conducting a nationwide project that uses AI and multi-omics analyses for molecular profiling in patients with advanced cancers, aiming to create new treatments and diagnostics.
  • The project includes the CIRCULATE-Japan study, focusing on precision medicine for resectable solid tumors and requires substantial data storage in a high-tech supercomputing system called VAPOR CONE.
  • As of December 2023, over 24,000 patients have been registered, with 5.0% of those in advanced solid tumors participating in matched clinical trials, showing a 29.2% response rate and significantly improved survival rates compared to those not receiving matched therapies.
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Article Synopsis
  • The study aims to analyze the mutational patterns in circulating tumor DNA (ctDNA) and tumor tissue from patients with hormone receptor-positive, HER2-negative metastatic breast cancer who were treated with abemaciclib and endocrine therapy.
  • Blood and tissue samples were collected from 97 female patients, with assessments of genomic alterations and clinical characteristics, focusing on changes before and after treatment.
  • Results indicated specific genetic mutations common in the patient population, revealing an increase in certain alterations after treatment, thereby enhancing understanding of the mutational landscape in this type of breast cancer.
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Advanced gastric and gastroesophageal junction cancers (GC/GEJCs) harbor diverse molecular signatures, highlighting the need for intricate evaluations to identify potential therapeutic targets. Although whole-transcriptome sequencing (WTS) has emerged as a useful tool for understanding these molecular intricacies, its clinical implications have yet to be fully elucidated. This study evaluated the correlation between immunohistochemistry (IHC) and WTS, compared their clinical significance, and identified potential therapeutic targets undetectable through IHC alone.

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Article Synopsis
  • * The objective was to assess if a learning program sharing treatment protocols for low-evidence biomarkers could align MTB recommendations and evaluate the effectiveness of an AI-based annotation system.
  • * The study involved 47 participants and 50 simulated cases, comparing treatment recommendation concordance before and after the learning program, with the aim to achieve high agreement levels post-learning.
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Importance: Quality assurance of molecular tumor boards (MTBs) is crucial in cancer genome medicine.

Objective: To evaluate the concordance of recommendations by MTBs and centrally developed consensus treatment recommendations at all 12 leading institutions for cancer genomic medicine in Japan using 50 simulated cases.

Design, Setting, And Participants: This was a prospective quality improvement study of 50 simulated cancer cases.

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In Japan, comprehensive genomic profiling (CGP) tests for refractory cancer patients have been approved since June 2019, under the requirement that all cases undergoing CGP tests are annotated by the molecular tumor board (MTB) at each government-designated hospital. To investigate improvement in precision oncology, we evaluated and compared the proportion of cases receiving matched treatments according to CGP results and those recommended to receive genetic counseling at all core hospitals between the first period (11 hospitals, June 2019 to January 2020) and second period (12 hospitals, February 2020 to January 2021). A total of 754 and 2294 cases underwent CGP tests at core hospitals in the first and second periods, respectively; 28 (3.

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Comprehensive genomic profiling is increasingly used to facilitate precision oncology based on molecular stratification. In addition to conventional tissue comprehensive genomic profiling, comprehensive genomic profiling of circulating tumor DNA has become widely utilized in cancer care owing on its advantages, including less invasiveness, rapid turnaround time, and capturing heterogeneity. However, circulating tumor DNA comprehensive genomic profiling has some limitations, mainly false negatives due to low levels of plasma circulating tumor deoxyribonucleic acid and false positives caused by clonal hematopoiesis.

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Article Synopsis
  • Bartholin gland carcinomas (BGCs) are rare tumors with no prior molecular studies, limiting treatment options; specifically, adenoid cystic carcinomas (ACCs) of BGCs have unclear genetic profiles compared to those in salivary glands.
  • Targeted gene sequencing revealed KRAS and KDM6A mutations in two patients with BG-ACC, suggesting different carcinogenic pathways than salivary gland ACCs, particularly since KRAS mutations were not previously reported in the latter.
  • Understanding the genetic mechanisms of BG-ACC can lead to novel treatment approaches, including gene-targeted therapies that could enhance patient outcomes.
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We established an outpatient service in November 2017 to provide cancer gene profiling test services to cancer patients. To date, we have seen approximately 100 patients. Our staff includes genetic counselors and nurses specialized in genetic medicine.

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Precision medicine, which includes comprehensive genome sequencing, is a potential therapeutic option for treating high-grade serous carcinoma (HGSC). However, HGSC is a heterogeneous tumor at the architectural, cellular, and molecular levels. Intratumoral molecular heterogeneity currently limits the precision of medical strategies based on the gene mutation status.

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Receptor tyrosine kinases (RTKs) are involved in oncogenesis and disease progression for many cancers. Inhibitors targeting them are vigorously developed and some of them are tested in the clinical setting. Amplifications of certain RTKs (c-Met, FGFR2 and ErbB2) have been associated with human gastric cancer progression.

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Objective: Serum IgG4 levels are frequently elevated in patients with autoimmune pancreatitis (AIP). AIP is sometimes associated with various extrapancreatic lesions. This study examined whether there is a correlation between serum IgG4 levels and associated extrapancreatic lesions in AIP patients.

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Objectives: It is of utmost importance that autoimmune pancreatitis (AIP) be differentiated from pancreatic cancer (PC) because some AIP cases undergo unnecessary laparotomy or pancreatic resection on suspicion of PC. This study aimed to develop an appropriate strategy for differentiating between AIP and PC.

Methods: Clinical, serological, and radiological features of 17 AIP patients forming a masslike lesion on pancreas head and 70 patients with pancreatic head cancer were compared.

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Abnormal nuclear accumulation of beta-catenin (CTNNB1) plays one of the key roles in the upregulation of the Wnt signalling pathway that can cause acceleration of cell proliferation. ICAT, inhibitor of beta-catenin and TCF4/beta-catenin-interacting protein, was isolated and mapped to 1p36, a frequent target for LOH in many human cancers. We have previously observed that a number of tumors showing abnormal accumulation of the CTNNB1 protein do not harbor a mutation of the CTNNB1 gene.

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