A CFSE division profile of anti-CD3/anti-CD28 antibody-stimulated T cells isolated from control and tumor-bearing mice is shown in Figure 4A. Discrete division cycles could be visualized by means of different CFSE signal peaks in case of T cells isolated from healthy mice, whereas T cells from tumor-bearing mice failed to proliferate in response to anti-CD3/anti-CD28 antibody. This evidence concerns the gene CD28 and neoplasm.