Figure 2C shows that CD3+ CD56+ CIK cells from 6 subjects 5 GIST and 1 OS) maintained the initial high levels of CD38 with a mean value of 62.5% (min 53.2%, max 75.0%) vs. 92.5% (min 81.5%, max 98.8%); CD39 had a mean value of 13.2% (min 2.3%, max 23.5%) vs. 53.3% (min 32.2%, max 75.2%) associated to a significant increase at day 21 of the expression of CD26 as compared to resting PBMC with a mean value of 20.5% (min 6.8%, max 23.1%) vs. 91.2% (min 76.5%, max 96.5%), along with minimal CD203a up-regulation with a mean value of 15.1% (min 2.5%, max 24.1%) vs. 23.5% (min. Here, DPP4 is linked to gastrointestinal stromal tumor.