Chemotherapy resistance molecular mechanism in small cell lung cancer.

The malignancy of small cell lung cancer (SCLC) is the highest amongst all lung cancer types. It is characterized by rapid growth, early occurrence of distant sites metastasis, poor survival rates and is initially sensitive to chemotherapy and radiotherapy. However, most patients eventually relapse or disease progresses because of chemotherapy resistance. Because of lack of effective second-line therapies, the prognosis of SCLC patients is usually poor. For the development of novel therapies, it is necessary to understand the mechanisms of chemotherapy resistance in SCLC. The mechanism is complex, because multiple factors could lead to chemotherapy resistance. An overview of multiple events triggering the formation of chemotherapy resistance phenotypes of SCLC cells is discussed.