[Association of polycyclic aromatic hydrocarbons exposure scores and alteration of mitochondrial DNA copy number with female lung cancer risk among never smokers].

Abstract

Objective: To investigate the association of exposure to polycyclic aromatic hydrocarbons exposure scores and alteration of relative mitochondrial DNA copy number of blood with female lung cancer risk among never smokers.

Methods: From August 2017 to August 2021, we enrolled all physician diagnosed new cases(n=465) of non-smoking female lung cancer from 12 tertiary and above hospitals in Liaoning, Jiangsu, Anhui and Qinghai provinces. And we selected matched non-smoking controls(n=463) by age and sex who were non-cancer and noncommunicable disease patients from the same hospital visited by the cases. Blood mitochondrial DNA copy number was detected by quantitative real-time polymerase chain reaction and estimated by relative quantification. We performed random forest and logistic regression to analyze the association of polycyclic aromatic hydrocarbons exposure scores and relative mitochondrial DNA copy number with the risk of female lung cancer among never smokers. We further analyzed the mediating effect and interaction models of polycyclic aromatic hydrocarbons exposure scores and mitochondrial DNA copy number levels on lung cancer in non-smoking women.

Results: The M(P25, P75) of polycyclic aromatic hydrocarbons exposure scores for cases and controls were 0.05(0.13, 0.16) and 0.08(0.24, 0.13), polycyclic aromatic hydrocarbons exposure scores of the cases was significantly higher than the controls(U=92130, P<0.05). The M(P25, P75) of mitochondrial DNA copy number for cases and controls were 0.90(0.71, 1.14) and 1.00(0.79, 1.21), mitochondrial DNA copy number of the cases was significantly lower than the controls(U=122559, P<0.05). Random forest and multivariable logistic regression analysis showed that the risk of lung cancer in non-smoking women increased with the increase of polycyclic aromatic hydrocarbons exposure scores(P_(trend)<0.05) and the decrease of relative mitochondrial DNA copy number(P_(trend)<0.05). The additive interaction between polycyclic aromatic hydrocarbons exposure scores and mitochondrial DNA copy number in non-smoking female lung cancer was statistically significant [API = 0.43(95%CI 0.19-0.67), SI = 2.84(95%CI 1.25-6.48). Mediation analysis showed mitochondrial DNA copy number had no significant mediating effect on the association between polycyclic aromatic hydrocarbons exposure scores and lung cancer in non-smoking women(Za×Zb: 95%CI-0.044-0.055).

Conclusion: Minimize unnecessary polycyclic aromatic hydrocarbons exposures might significantly reduce the lung cancer risk among non-smoking women. Alteration of mitochondrial DNA copy number might become a potential biomarker in risk prediction of lung cancer of non-smoking women.