Immune Checkpoints in Colorectal Cancer

Aim: To examine the role of PD-L1/PD1 in immune cell-mediated cytotoxicity in colorectal cancer patients. Objectives: 1. Comprehensive investigation of PD-L1/PD1 in colorectal cancer in association with chemotherapy responses and immune activities; 2. Examine the functional role of PD-L1/PD1 targeting in immune cell-mediated cytotoxicity. Hypothesis: It is hypothesized that PD-L1/PD1 has pivotal role on the immune cell-mediated cytotoxicity in colorectal cancer. Significances: The current study will elucidate the significance of PD-L1/PD1 on chemo-resistance and the effect on immune cells and their functional properties. The study will enhance the understanding on chemotherapy response and immune evasion. The long-term goal is to provide the crucial information on oncoimmunology to improve efficacy of immunotherapy in cancer treatment. Subjects: Only those patients for whom colorectal cancer is the indicated clinical diagnosis will be recruited in the current study. Possible participants will be patients undergoing tumor resection or endoscopic examination at the Department of Surgery, Prince of Wales Hospital, Shatin, Hong Kong. Specimens will be collected from sixty-eight colorectal cancer patients. The estimated duration for collection of all the necessary samples will be two years. With at least one year of follow-up information, the proposed study should be completed in three years. For the current study, single blood sample (10 ml of peripheral blood in EDTA) will be drawn before the operation or endoscopic session. A small portion of the tumor and non-tumor tissue tissues from resected specimens or biopsy tissues will be collected for histological evaluation, primary culture and for comparison of the genetic and protein components in the blood specimen.