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.

Rationale:

The purpose of this program is to obtain consent for and to outline the process for collection of fresh blood sample from healthy humans and colorectal cancer patients before and after surgical resection.

Procurement of fresh human blood is required for the following:

• To compare NK cell function, measured by two different assays, in healthy humans and newly diagnosed colorectal cancer patients at the Ottawa Hospital.
• To compare NK cell function, measure by two different assays in colorectal surgery patients preoperatively and at various time points postoperatively.

Inclusion Criteria:

• Subjects who have had a recent diagnosis of cancer (any stage) and will be undergoing surgery (cancer group)
• Subjects who are being seen by their physician for other reasons, or healthy volunteers (control group)
• Subjects who provide informed consent to participate in the trial
• Subjects >40 years of age

Exclusion Criteria:

• Inability or unwillingness to sign informed consent form
• History of active viral or bacterial infection
• History of prescription use of immunosuppressive drugs within the last six months
• History of anticancer treatments including radiation or chemotherapy
• History of autoimmune disorders (rheumatoid arthritis, multiple sclerosis, systemic lupus erythematosus, inflammatory bowel disease including Crohn's disease, Type I diabetes, Guillain-Barré syndrome)
• Known HIV, Hepatitis B, or Hepatitis C infection