I thought any of these experiments are carried out on two sets of cells. One normal and the other cancerous. Both exposed to the same test environment and treat

I thought any of these experiments are carried out on two sets of cells. One normal and the other cancerous. Both exposed to the same test environment and treatment -- shear in this case. And when they claim "70% of cancerous cells died" they mean 70% more of the cancerous cells died than that of the normal cells, where "more" is defined in some acceptable standard.