Human Blood Specimen Collection to Evaluate Immune Cell Function

Natural killer (NK) cells are leukocytes of the innate immune system and play a central role in the control of cancer metastases. NK cells and other innate immune cells often do not function well in patients with cancer and are also profoundly suppressed after cancer surgery. Dr. Auer's Lab and others have shown that NK cells are critically important in the clearance of tumor metastases and that their impairment can be recovered with immune therapy augmenting the innate immune system. Several studies suggest that cancer patients have depressed NK cell cytotoxicity as compared to healthy controls but that following resection of the cancer, NK cell cytotoxicity returns to normal levels. In this observational study, the investigators will measure NK cell cytotoxicity by the gold standard method (51Cr, a chromium51 release assay) and by a new interferon-ɣ (IFN-ɣ) based assay (NK-Vue™) in healthy humans and colorectal cancer (CRC) surgery patients seen a The Ottawa Hospital. The results of this study will determine if the NK-Vue™ is able to discriminate between healthy human volunteers and newly diagnosed cancer patients and is sufficiently sensitive to detect transient NK cell suppression immediately following surgery.