TY - JOUR AB - The local mechanisms of antitumor immune defense determine the development and organization of the tumor microenvironment, and the composition and relative proportions of the inflammatory cell population affect the quality and characteristics of the immune response. The aim of the present study was to conduct a quantitative morphological evaluation of two types of tumor‑infiltrating lymphocyte (TILs) populations, including those located in the stroma and intraepithelial cancer structures, in the invasive front and the center of the tumor in patients with colorectal cancer (CRC). The study included 160 patients with CRC who had undergone surgery. The tissue material was stained with hematoxylin and eosin, as used in routine histopathological diagnosis, and the two TIL populations were observed and counted with light microscopy. The relative extent of infiltration of stromal and intraepithelial TILs into the front and center of the primary tumors was similar. The extent of infiltration by stromal TILs was negatively correlated with the morphological features of tumor progression including the cancer infiltration of blood vessels (P=0.016), the invasion of lymph vessels (P=0.007), perineural invasion (P=0.036), lymph node involvement (P=0.047) and distant metastases (P=0.032). The infiltration by intraepithelial TILs was positively correlated with a desmoplastic reaction (P=0.002). Disease‑free survival time was statistically shorter in patients without intraepithelial TILs in the center of the primary tumor mass (P=0.049; hazard ratio = 1.45). These results confirm that the infiltration of TILs into the invasive front and center of the tumor in patients with CRC serves an important role in the invasion and progression of the disease, and should be considered in routine histopathological examinations. AD - Department of Pathomorphology, Comprehensive Cancer Center, 15‑027 Bialystok, Poland Department of Medical Pathomorphology, Medical University of Bialystok, 15‑269 Bialystok, Poland Department of General Pathomorphology, Medical University of Bialystok, 15‑269 Bialystok, Poland AU - Jakubowska,Katarzyna AU - Kisielewski,Wojciech AU - Kańczuga‑Koda,Luiza AU - Koda,Mariusz AU - Famulski,Waldemar DA - 2017/12/01 DO - 10.3892/ol.2017.7013 EP - 6432 IS - 6 JO - Oncol Lett KW - tumor‑infiltrating lymphocytes colorectal cancer immune response PY - 2017 SN - 1792-1074 1792-1082 SP - 6421 ST - Stromal and intraepithelial tumor‑infiltrating lymphocytes in colorectal carcinoma T2 - Oncology Letters TI - Stromal and intraepithelial tumor‑infiltrating lymphocytes in colorectal carcinoma UR - https://doi.org/10.3892/ol.2017.7013 VL - 14 ER -