Tumor immune microenvironment is influenced by frameshift mutations and tumor mutational burden in gastric cancer

• H. Kim ^[1] ; Y. J. Heo ^[2] ; Y. A. Cho ^[3] ; S. Y. Kang ^[1] ; S. Ahn ^[1] ; K. M. Kim ^[1]
  1. [1] Sungkyunkwan University

     Sungkyunkwan University

     Corea del Sur

     
  2. [2] The Samsung Advanced Institute for Health Sciences & Technology (SAIHST), Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
  3. [3] Department of Pathology, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang, Republic of Korea

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• Localización: Clinical & translational oncology, ISSN 1699-048X, Vol. 24, Nº. 3 (Marzo), 2022, págs. 556-567
• Idioma: inglés
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  • Purpose Immunoscore can effectively predict prognosis in patients with colon cancer; however, its clinical application is limited. We modified the Immunoscore and created a tumor immune microenvironment (TIM) classification system for gastric carcinoma. Unlike previous studies that used small sample sizes or focused on particular immune-cell subtypes, our simplified system enables pathologists to classify gastric carcinomas intuitively using H&E-stained sections.

    Methods Samples from 326 patients with advanced gastric carcinoma were reviewed and analyzed by pathologists using simple determination and digital image analysis. Comprehensive results of cancer-panel sequencing, Epstein-Barr‒virus (EBV) status, and PD-L1, HER2, ATM, PTEN, MET, FGFR2, and EGFR immunohistochemistry were evaluated with respect to the TIM class.

    Results The TIM was classified as “hot” (n = 22), “immunosuppressed” (n = 178), “excluded” (n = 83), or “cold” (n = 43). TIM category was significantly associated with numbers of frameshift mutations (P < 0.001) and high tumor mutational burden (P < 0.004), and predicted overall survival. It was also significantly associated with age, histological type, degree of fibrosis, PD-L1 expression, loss of ATM and PTEN expression (P < 0.001), sex, EBV positivity, and HER2 overexpression (P < 0.04). “Hot” tumors were frequent in PD-L1 expressing and EBV-positive samples, and in those with ATM and PTEN loss. “Excluded” tumors were frequent in HER2-positive cases, whereas “cold” tumors were more frequent in younger patients with poorly cohesive histology and high fibrosis levels.

    Conclusions TIM classification system for gastric carcinoma has prognostic significance and results in classes that are associated with molecular characteristics.