Radiosensitivity Differences between Mutant and Wild-Type Lung Cancer Cells are Larger at Lower Doses.

In the era of precision medicine, radiotherapy strategies should be determined based on genetic profiles that predict tumor radiosensitivity. Accordingly, pre-clinical research aimed at discovering clinically applicable genetic profiles is needed. However, how a given genetic profile affects cancer cell radiosensitivity is unclear. To address this issue, we performed a pilot in vitro study by utilizing mutational status as a model for genetic profile. Clonogenic assays of mutant ( = 6) and wild-type ( = 9) non-small cell lung carcinoma (NSCLC) cell lines were performed independently by two oncologists. Clonogenic survival parameters SF, SF, SF, SF, mean inactivation dose (MID), D, D, α, and β were obtained using the linear quadratic model. The differences in the clonogenic survival parameters between the mutant and wild-type cell lines were assessed using the Mann-Whitney U test. As a result, for both datasets, the values for SF, SF, D, α, and α/β were below 0.05, and those for SF were lowest. These data indicate that a genetic profile of NSCLC cell lines might be predictive for their radiation response; i.e., mutant cell lines might be more sensitive to low dose- and low fraction sized-irradiation.