Anger suppression mediates the relationship between optimism and natural killer cell cytotoxicity in men treated for localized prostate cancer

Objective: This study evaluated relations among optimism, depression, anger suppression and natural killer cell cytotoxicity (NKCC) in 61 men treated for localized prostate cancer (PC). Method: All participants were assessed at a single time point where demographics, optimism, depression and anger suppression were measured. We also collected peripheral venous blood to assess NKCC. Results: Results showed that greater optimism was associated with greater NKCC (β=.27, P<.05), less depression (β=-.63, P<.001) and less anger suppression (β=-.29, P<.05). Furthermore, less anger suppression (β=-.35, P<.01) was associated with greater NKCC. In a hierarchical regression model controlling for depression and then anger suppression, the relationship between optimism and NKCC became nonsignificant [β=.18, t(56)=1.51, P=.14], while anger suppression remained significantly correlated with NKCC [β=-.29, t(56)=-2.40, P<.05]. Conclusions: Results suggest that optimism is associated with NKCC and a greater ability to adaptively express anger. Furthermore, it appears that less anger suppression partially mediates the relationship between optimism and NKCC.