Tertiary Lymphoid Structures in Colorectal Cancers and Their Prognostic Value

BACKGROUND: Tumor-infiltrating lymphocytes (TIL) in tumour stroma are considered to be involved in the elimination of malignant cells and prevention of metastasis formation. TIL consist of T lymphocytes including cytotoxic lymphocytes that are a constituent part of the effector mechanism of anti-tumour immunity and B lymphocytes that can form tertiary lymphoid structures (TLS). TLS has been described in several solid tumours and colorectal carcinoma (CRC), and the influence on the local and systemic anti-cancer response. AIM: This study aimed to quantify the presence of TLS in CRC patients and to determine their role in tumour progression. PATIENTS AND METHODS: The study included 103 patients with CRC who underwent surgery at the University Clinic of Digestive Surgery in Skopje, whose operative material was analysed at the Institute of Pathology, Medical Faculty in Skopje. The density of TLS was determined and correlated with the neoplasm status of local growth (T), positive lymph nodes, lymphatic invasion, and stage of the disease and tumour grade. RESULTS: The density of TLS was significantly higher in patients with higher stage, lower T status, and negative lymph nodes, in patients with no lymphatic invasion and with better-differentiated tumours. CONCLUSION: The density of TLS plays an important role in controlling the tumour growth, and it can be a parameter for neoplasm progression in CRC patients. The density of TLS influences the control of tumour progression.