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

This study evaluated relations among optimism, depression, anger suppression and natural killer cell cytotoxicity (NKCC) in 61 men treated for localized prostate cancer (PC).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 showed that greater optimism was associated with greater NKCC (beta=.27, P<.05), less depression (beta=-.63, P<.001) and less anger suppression (beta=-.29, P<.05). Furthermore, less anger suppression (beta=-.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 [beta=.18, t(56)=1.51, P=.14], while anger suppression remained significantly correlated with NKCC [beta=-.29, t(56)=-2.40, P<.05].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.