The adaptive immune response to colorectal cancer: From the laboratory to clinical practice

IntroductionAnalysis of the adaptive immune system in the microenvironment of colorectal cancer is suggested to offer new insights into tumour biology and prognostic information independent of TNM staging. We aimed to review recent findings to investigate the potential for clinical use.MethodsRelevant papers were identified through online searches regarding tumour infiltrating lymphocytes (TIL) in colorectal cancer. Identified papers were studied, focusing on clinically applicable uses for TIL data in the management of colorectal cancer.FindingsThe majority of identified studies were retrospective and observational in nature. The widest TIL investigation was in post resection prognosis but TIL subtypes, counts and methodology showed variability between studies. Recent reports explored TIL in predicting response to adjuvant and neoadjuvant treatments.ConclusionAn increasing body of evidence supports that visibility of colorectal cancer to immune attack is substantial and that it limits disease progression. Analysis of the adaptive immune infiltrate in resected colorectal cancer specimens offers prognostic information which is independent of conventionally measured parameters and potentially superior in predictive value.