Enigmas in tumor resistance to kinase inhibitors and calculation of the drug resistance index for cancer (DRIC)

Seven parameters: 1. Drug type, 2. tumor type, 3. presence of metastases or phenotypic change, 4. tumor cell number, 5. net growth rate (proliferation minus cell death), 6. inherited genetic- and 7. epigenetic- variations are crucial for drug responses. It is envisaged that it might become possible to calculate a clinically relevant Drug Resistance Index for Cancer (DRIC) for each patient.