The focus of this descriptive comparative study was to examine the relationship between gender and depression and immune system function in patients with colorectal cancer. The research questions were answered through secondary analysis, using data obtained from the answers of 117 men and women (71 men and 46 women) enrolled in a colorectal cancer study conducted between 1990 and 1991 in Pennsylvania. Descriptive statistics were used to characterize the sample, and general estimating equations were used to analyze depression and immune system function between men and women. Depression was measured by the Beck Depression Inventory, and immune system function was measured by natural killer cell levels. Results indicated that women reported higher levels of depression at all points in time, but the results were not statistically significant (B=2.065, p=.151). Age was statistically significant (B=4.180, p=.041). Women did not demonstrate statistically significantly lower NK cell levels than men (B=.271, p=.603) using GEE, although at all points in time, men\u27s NK cell levels were higher than women\u27s. Age was not a significant factor in the NK cell level differences (B=3.667, p=.056). The study was confounded by the relatively small sample size, and the high drop-out rate
