Tumour Lymphocytic Infiltration, Its Structure and Influence in Colorectal Cancer Progression

BACKGROUND: The role of the immune system in the control of tumour progression has been stressed, recently. Many studies indicate the fact that the immune system can prevent tumour progression in several types of human malignant neoplasms including colorectal cancer. According to some authors, a higher density of “tumour-associated lymphocytes” (TAL), in malignant neoplasms, correlate with prolonged survival of patients. AIM: This study aims to determine the structure and the influence of the immune cells, TAL, in the progression of colorectal cancer (CRC). PATIENTS AND METHODS: The study included 103 patients with CRC operated at the University Clinic of Digestive Surgery in Skopje, whose operative material was analysed at the Institute of Pathology, Medical Faculty in Skopje. The structure of tumor-associated cells and their density were determined and were correlated with neoplasm’s grade, local growth (T), positive lymph nodes, lymphatic invasion and stage of the disease. RESULTS: CD4+, CD8+ and CD20+ lymphocytes (Ly) were found in TAL. The density of TAL was significantly different in neoplasms with different T status, lymphatic invasion, patients with and without nodal metastasis and patients with a different stage of the disease. The density of CD4+, CD8+, and CD20+ cells were significantly different in neoplasms with different T. The density of CD8+ and CD20+ lymphocytes was lower in patients with nodal metastasis and higher stage. CONCLUSION: The density of tumor-associated lymphocytes can anticipate the disease progression in patients with colorectal cancer, and the density of TAL influences the control of tumour progression.