Cancer Immunotherapy: The Checkpoint between Chronic Colitis and Colorectal Cancer

SIMPLE SUMMARY: Inflammatory bowel disease (IBD) affects the colon and is divided in two main pathologies, ulcerative colitis and Crohn’s disease. It is characterised by inflammation, which is managed by anti-inflammatory treatments, however, in the long term they lose effectiveness. Chronic inflammation/chronic colitis pre-disposes the person to increased risk of colorectal cancer (CRC). Checkpoint markers has revolutionised immunotherapeutic treatments especially in colorectal cancer. Here, we present different checkpoint inhibitors and their role in IBD and CRC. ABSTRACT: Inflammatory Bowel Disease (IBD) is a group of diseases that cause intestinal inflammation and lesions because of an abnormal immune response to host gut microflora. Corticosteroids, anti-inflammatories, and antibiotics are often used to reduce non-specific inflammation and relapse rates; however, such treatments are ineffective over time. Patients with chronic colitis are more susceptible to developing colorectal cancer, especially those with a longer duration of colitis. There is often a limit in using chemotherapy due to side effects, leading to reduced efficacy, leaving an urgent need to improve treatments and identify new therapeutic targets. Cancer immunotherapy has made significant advances in recent years and is mainly categorized as cancer vaccines, adoptive cellular immunotherapy, or immune checkpoint blockade therapies. Checkpoint markers are expressed on cancer cells to evade the immune system, and as a result checkpoint inhibitors have transformed cancer treatment in the last 5–10 years. Immune checkpoint inhibitors have produced long-lasting clinical responses in both single and combination therapies. Winnie mice are a viable model of spontaneous chronic colitis with immune responses like human IBD. Determining the expression levels of checkpoint markers in tissues from these mice will provide insights into disease initiation, progression, and cancer. Such information will lead to identification of novel checkpoint markers and the development of treatments with or without immune checkpoint inhibitors or vaccines to slow or stop disease progression.