CD28 and cancer: Corroborating the observations on the absolute cell numbers, the proportion of CD28+CD57+ cells at the 3rd month was significantly higher in the stage III patients than the controls (Fig. 4f); similarly, the proportion of CD28-CD57+ cells among the stage IV cancer patients at all sampling points was significantly higher than among the control group, while the proportion at baseline was also higher than for the stage III patients (Fig. 4h).