Social support, psychological distress, and natural killer cell activity in ovarian cancer

Psychosocial stress has been related to impaired immunity in cancer patients. However, the extent to which these relationships exist in immune cells in the tumor microenvironment in humans has not been explored. We examined relationships among distress, social support, and natural killer (NK) cell activity in ovarian cancer patients in peripheral-blood mononuclear cells (PBMC), ascitic fluid, and tumor-infiltrating lymphocytes (TIL).

Patients awaiting surgery for a pelvic mass suspected of being ovarian cancer completed psychological questionnaires and gave a presurgical sample of peripheral blood. Samples of tumor and ascites were taken during surgery, lymphocytes were then isolated, and NK cytotoxicity and percentage were determined. The final sample, which was confirmed by surgical diagnosis, included 42 patients with epithelial ovarian cancer and 23 patients with benign masses.

Peripheral NK cell activity was significantly lower among ovarian cancer patients than in patients with benign masses. Among ovarian cancer patients, NK cytotoxicity in TIL was significantly lower than in PBMC or ascitic fluid. Social support was related to higher NK cytotoxicity in PBMC and TIL, adjusting for stage. Distress was related to lower NK cytotoxicity in TIL. A multivariate model indicated independent associations of both distress and social support with NK cell activity in TIL.

Psychosocial factors, such as social support and distress, are associated with changes in the cellular immune response, not only in peripheral blood, but also at the tumor level. These relationships were more robust in TIL. These findings support the presence of stress influences in the tumor microenvironment.