That is why combining treatments that have different mechanisms of action can kill more cancer cells and reduce the chance that drug resistance will emerge most of the research on drug resistance has focused on identifying genetic mechanisms such as mutations that alter a protein such that it impairs the binding of a drug research is revealing the importance of additional mechanisms of drug resistance such as epigenetic factors that regulate the activity of genes and the dynamics between . Cancer drug resistance one of the main causes of failure in the treatment of cancer is the development of drug resistance by the cancer cells this is a very serious problem that may lead to recurrence of disease or even death this section is intended to introduce some of the main ways in which cancer cells can resist treatments. Although targeted therapy is yielding promising results in the treatment of specific cancers drug resistance poses a problem we develop a mathematical framework that can be used to study the principles underlying the emergence and prevention of resistance in cancers treated with targeted small molecule drugs. Drug resistance is a major obstacle that limits the effectiveness of cancer therapy many cancer cells acquire resistance mechanisms that allow them to survive apoptosis contributing to the