Genetic variants in PI3K/AKT pathway are associated with severe radiation pneumonitis in lung cancer patients treated with radiation therapy.

PI3K/AKT pathway plays important roles in inflammatory and fibrotic diseases while its connection to radiation pneumonitis (RP) is unclear. In this study, we explored the associations of genetic variants in PI3K/AKT pathway with RP in lung cancer patients with radiotherapy. Two hundred and sixty one lung cancer patients with radiotherapy were included in this prospective study (NCT02490319) and genotyped by MassArray and Sanger Sequence methods. By multivariate Cox hazard analysis and multiple testing, GA/GG genotype of AKT2: rs33933140 (HR=0.272, 95% CI: 0.140-0.530, P=1.3E-4, P-c=9.1E-4), and the GT/GG genotype of PI3CA: rs9838117 (HR=0.132, 95% CI: 0.042-0.416, P=0.001, P-c=0.006) were found to be strongly associated with a decreased occurrence of RPgrade 3. And patients with the CT/TT genotype of AKT2: rs11880261 had a notably higher incidence of RPgrade 3 (HR=2.950, 95% CI: 1.380-6.305, P=0.005, P-c=0.025). We concluded that the genetic variants of PI3K/AKT pathway were significantly related to RP of grade3 and may thus be predictors of severe RP before radiotherapy, if further validated in larger population.