Abstract
BACKGROUND: Previous studies have found that the presence and density of tumor-infiltrating T lymphocytes has significant prognostic value in colon and rectal cancer. However, there is a paucity of systematic reviews focusing on the role of tumor-infiltrating B lymphocytes (TIBLs) in colorectal cancer. The aim of this review was to assess the role of all known subsets of TIBLs implicated in colorectal cancer, as well as to identify the methodologies used for the identification of TIBLs and establish their prognostic value in the colorectal tumor microenvironment (TME). METHODS: A systematic literature search was conducted from 2000 to 2025 using the PubMed (Medline), Embase and Cochrane Library databases. Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines were followed to identify eligible studies. RESULTS: A total of 32 original papers involving 5766 individual patients met the inclusion criteria. Several B cell types in the immune TME of colon and rectal cancer were identified, each with specific roles and prognostic value. Several distinct methodologies were used for the identification of these cells, according to specific detection protocols used by various institutions. Certain immunological pathways through which these cells may be involved in the carcinogenesis of colorectal tumors have also been identified, which may potentially lead to the development of novel immunotherapy targets. CONCLUSIONS: We concluded that TIBLs play a significant role in the immune microenvironment of colorectal cancer, providing theoretical evidence for potential biomarkers which may constitute a valuable target for individualized treatment.