BIRC5 and cancer: When this model, which includes c-myc, cyclin A, cyclin B1, cyclin D1, CDK2, and survivin, was applied to the healthy non-smoking control group as a test set, we correctly classified 31/36 control patients as non-cancer using a cutoff value of 0.085 which maximizes the sensitivity and specificity of the logistic function at 81% and 97% respectively.