Association of P53 and ATM polymorphisms with risk of radiation-induced pneumonitis in lung cancer patients treated with radiotherapy.

Radiation-induced pneumonitis (RP) is the most common dose-limiting complication in lung cancer patients treated with radiotherapy. Accumulating evidence indicates that P53 and the ataxia telangiectasia-mutated protein (ATM)-dependent signaling response cascade play a crucial role in radiation-induced diseases. Consistent with this, our previous study showed that a functional genetic ATM polymorphism was associated with increased RP risk.To evaluate the role of genetic P53 polymorphism in RP, we analyzed the P53 Arg72Pro polymorphism in a cohort including 253 lung cancer patients receiving thoracic irradiation.We found that the P53 72Arg/Arg genotype was associated with increased RP risk compared with the 72Pro/Pro genotype. Furthermore, the P53 Arg72Pro and ATM -111G>A polymorphisms display an additive combination effect in intensifying the risk of developing RP. The cross-validation test showed that 63.2% of RP cases can be identified by P53 and ATM genotypes.These results indicate that genetic polymorphisms in the ATM-P53 pathway influence susceptibility to RP and genotyping P53 and ATM polymorphisms might help to identify patients susceptible to developing RP when receiving radiotherapy.