Among several cancer treatments, the main treatments that are commonly used to treat patients are Surgery, Radiotherapy, and Chemotherapy.

Surgery can remove majority of cancer cells (but not all) from the body, while combining radiotherapy with chemotherapy can effectively give better results for treating many types of cancer.

Recent chemotherapeutic agents are successful against primary tumor lesions and its residue after surgery or radiotherapy.

However, chemotherapy induces tumor heterogeneity derived from both normal and cancer cells and the heterogeneity within tumors, in turn, results in reducing effects of chemotherapy; contributing to the treatment failure and disease progression.

Chemoresistance is a major problem in the treatment of cancer patients, as cancer cells become resistant to chemical substances used in treatment, which consequently limits the efficiency of chemo agents. It is also often associated with tumors turning into more aggressive form and/or metastatic type. Accumulating evidences suggest that cancer stem cell (CSC) population, a subgroup of cancer cells, is responsible for the chemoresistance and cancer relapse, as it has ability to self-renew and to differentiate into the heterogeneous lineages of cancer cells in response to chemotherapeutic agents. CSCs are also able to induce cell cycle arrest (quiescent state) that support their ability to become resistant to chemo- and radiotherapy.