Risk of lung adenocarcinoma from smoking and radiation arises in distinct molecular pathways

• Published in: Carcinogenesis (New York) Vol. 40; no. 10; pp. 1240 - 1250
• Main Authors: Castelletti, Noemi, Kaiser, Jan Christian, Simonetto, Cristoforo, Furukawa, Kyoji, Küchenhoff, Helmut, Stathopoulos, Georgios T
• Format: Journal Article
• Language: English
• Published: UK Oxford University Press 16.10.2019
• Subjects: Adenocarcinoma of Lung - etiology; Adenocarcinoma of Lung - genetics; Adenocarcinoma of Lung - pathology; Adult; Aged; Aged, 80 and over; Biomarkers, Tumor - genetics; Female; Follow-Up Studies; Gene Expression Regulation, Neoplastic; Humans; Lung Neoplasms - etiology; Lung Neoplasms - genetics; Lung Neoplasms - pathology; Male; Middle Aged; Neoplasms, Radiation-Induced - etiology; Neoplasms, Radiation-Induced - genetics; Neoplasms, Radiation-Induced - pathology; Nuclear Weapons - statistics & numerical data; Prognosis; Radiation Exposure - adverse effects; Risk Factors; Signal Transduction; Smoking - adverse effects; Smoking - genetics; Survival Rate; Survivors - statistics & numerical data
• ISSN: 0143-3334; 1460-2180
• DOI: 10.1093/carcin/bgz036

Abstract KRAS mutations of lung adenocarcinoma (LADC) are associated with smoking but little is known on other exposure-oncogene associations. Hypothesizing that different inciting agents may cause different driver mutations, we aimed to identify distinct molecular pathways to LADC, applying two entirely different approaches. First, we examined clinicopathologic features and genomic signatures of environmental exposures in the large LADC Campbell data set. Second, we designed a molecular mechanistic risk model of LADC (M3LADC) that links environmental exposure to incidence risk by mathematically emulating the disease process. This model was applied to incidence data of Japanese atom-bomb survivors which contains information on radiation and smoking exposure. Grouping the clinical data by driver mutations revealed two main distinct molecular pathways to LADC: one unique to transmembrane receptor-mutant patients that displayed robust signatures of radiation exposure and one shared between submembrane transducer-mutant patients and patients with no evident driver mutation that carried the signature of smoking. Consistently, best fit of the incidence data was achieved with a M3LADC with two pathways: in one LADC risk increased with radiation exposure and in the other with cigarette consumption. We conclude there are two main molecular pathways to LADC associated with different environmental exposures. Future molecular measurements in lung cancer tissue of atom-bomb survivors may allow to further test quantitatively the M3LADC-predicted link of radiation to transmembrane receptor mutations. Moreover, the developed molecular mechanistic model showed that for low doses, as relevant e.g. for medical imaging, smokers have the same radiation risk compared with never smokers. We developed the first mechanistic model for risk prediction of LADC stratified by molecular driver pathway. Radiation is mainly acting in the transmembrane receptor-mutant pathway, whereas smoking is acting in the transducer-mutant pathway with no interaction.