Density of CD3+and CD8+tumor-infiltrating T lymphocytes as predictor of survival in colon cancer stage I-III

Introduction: The risk of recurrence after surgery for colon cancer is not only determined by cancer stage and molecular characteristics, but also by the tumor microenvironment. This study aims to assess the prognostic value of CD3+ and CD8+ T lymphocyte infiltration and the relation to mismatch repair (MMR) deficiency. Material and methods: The study cohort includes 289 patients with surgically treated colon cancer stage I-III (no adjuvant chemotherapy) with clinical- and follow-up data. Immunohistochemistry for CD3+ and CD8+ T lymphocytes and MMR proteins MLH1, MSH2, MSH 6 and PMS2 was performed on Tissue Micro Arrays. (Results were available from 242/258 patients, respectively). Tumors were characterized as MMR deficient/proficient according to expression pattern. Densities of CD3+ and CD8+ lymphocytes were assessed within the tumor margins (tumor infiltrating lymphocytes, TILs) and stroma Results: MMR deficiency (60 patients, 24.8%) was significantly associated with high density of CD3+ and CD8+ TILs and stromal lymphocytes (p Conclusions: Our results support the prognostic impact of tumor infiltrating CD3+ and CD8+ lymphocyte density in colon cancer stage I-III and indicate that a high TIL density is a stronger predictor of survival than MMR deficiency. Citation Format: Kjersti E. Hestetun, Luka Stanisavljevic, Mette P. Myklebust, Olav Dahl. Density of CD3+ and CD8+ tumor-infiltrating T lymphocytes as predictor of survival in colon cancer stage I-III [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3122.