MODEL RELEASED. Cancer research. Female researcher pipetting a sample containing breast cancer cells into a vessel. The number of cancer cells will be measured using the Coulter Counter at left. Each sample was treated for three days with a different concentration of a new anticancer (chemotherapy) drug. Anticancer drugs are designed to stop cancer cells from proliferating. From these results, the relationship between the concentration of the drug and its inhibition of cancer cell growth can be determined. This is one of the first stages in the evaluation of a new anticancer drug.