PARP inhibitors in small cell lung cancer: The underlying mechanisms and clinical implications

Since the concept, DNA damage repair has been stated as a natural biological event, and research has increas-ingly revealed its strong association to tumors, aging, immunity, biochemical detection, and other factors. The discovery of abnormal DNA repair in cancers has been heralded as a paradigm shift in the treatment of malig-nancies. A poly (ADP-ribose) polymerase (PARP) activates poly (ADP-ribosylation) to repair single-strand DNA breaks after DNA damage. In some cancers, such as breast cancer and gastric cancer, a PARP inhibitor can target the DNA damage response pathway, prevent DNA repair, and induce homologous recombination deficiency (HRD) tumors to create the phenomena of synthetic lethality. Increasingly, clinical trials are being submitted to research the uses of PARP inhibitors in various types of cancers. Small cell lung cancer (SCLC) is a quickly growing malignancy with numerous therapeutic limitations and a dismal prognosis. Sequencing of mutant genes revealed multiple gene connections that may contribute to its carcinogenesis, indicating a viable study direction. Furthermore, the therapy of SCLC with PARP inhibitors has been further explored. The mechanism of PARP action, as well as the advancement of its preclinical and clinical applications in SCLC, will be discussed in this review.