In summary, there is substantial evidence from both healthy populations as well as individuals with cancer linking psychological stress with immune dysregulation. Stress may also enhance carcinogenesis through alterations in DNA repair and/or apoptosis [31-33]. In addition, the possibility that psychological interventions may enhance immune function and survival among cancer patients is still an open question [43, 44], as is the evidence suggesting that social support may be a key psychological mediator. However, these studies and others suggest that psychological or behavioral factors could influence the initiation/progression of cancer. Further studies to explain these relationships need to be performed.