Additional file 1: Table S1. List of investigated SNPs (AhR/Wnt-markers and LC-markers). Table S2. Association of AhR/Wnt-marker within subgroups. Table S3. Association of markers reported elsewhere. Table S4. Score composition and importance ratio. Table S5. Discriminability of prediction scores. Table S6. Prediction accuracy of the decision trees. Table S7. Prediction accuracy in never smokers by histological subtypes. Table S8. Expression in normal tissue of the lung according LungGENS. Table S9. Expression in normal tissue of the lung according the Human Protein Atlas. Figure S1. Association of AhR/Wnt-markers within never and ever smokers. Figure S2. Decision tree for overall LC. Figure S3. LC-risk score: model selection and ROCs for overall LC. Figure S4. LC-risk score: model selection and ROCs for SCLC and Never smoker. Figure S5. Decision tree for early onset LC (age ���55 years). Figure S6. Decision tree for SqCLC. Figure S7. Decision tree for SCLC. Figure S8. Decision tree for ever smoker. Figure S9. Expression profiles according to the Human Protein Atlas.