Asthma and Risk of Lung Cancer: A Mendelian Randomization Study

Date 24 November 2018
Event ESMO Asia 2018 Congress
Session Poster display - Cocktail
Topics Thoracic Malignancies
Presenter Huaqiang Zhou
Citation Annals of Oncology (2018) 29 (suppl_9): ix139-ix142. 10.1093/annonc/mdy445
Authors H. Zhou1, Y. Zhang1, W. Fang1, Y. Huang1, Y. Yang1, S. Hong1, G. Chen1, S. Zhao1, J. Liu2, H. Zhao1, Z. Li1
  • 1Department Of Medical Oncology, Sun Yat-sen University Cancer Center, 510000 - Guangzhou/CN
  • 2Zhongshan School Of Medicine, Sun Yat-sen University, 510000 - Guangzhou/CN

Abstract

Background

Asthma has been associated with lung cancer in observational studies. However, the causality of this association is still uncertain. Here we conduct a two sample mendelian randomisation study to assess whether asthma is causally associated with lung cancer.

Methods

The main analysis used publically available genetic summary data from two large consortiums (GABRIEL Consortium and ILCCO Consortium. We used 7 single nucleotide polymorphisms (SNPs) associated with asthma as instrumental variables in MR analysis, based on results from the GABRIEL consortium (10365 asthma cases and 16110 controls; European ancestry). For each of the 7 SNPs associated with asthma, we retrieved their summary data from ILCCO Consortium (11348 cases and 15861 controls; European ancestry). We used an inverse-variance weighting (IVW) to obtain the associations of asthma with lung cancer, and its subtypes (adenocarcinoma (LUAD) and squamous cell carcinoma (LUSC)). We also performed several sensitivity analyses to assess potential violation of MR assumptions.

Results

Asthma was not significantly associated with risk of lung cancer (odds ratio [OR], 1.01; 95% confidence interval [CI], 0.92-1.11; P = 0.859). Weighted median (OR, 1.06; 95% CI, 0.93-1.20; P = 0.383) and MR Egger analysis (OR, 1.00; 95% CI, 0.52-1.94; P = 0.996) showed similar effect estimates of asthma on lung cancer with wider CIs. The MR-Egger regression method also did not show any evidence for the presence of horizontal pleiotropy, as the P values for the intercept were large and the estimates adjusted for pleiotropy suggested null effects (intercept β = 0.001, P = 0.984). In a leave-one-out analysis, no single SNP was strongly driving the overall effect of asthma on lung cancer.

Conclusions

In this large study using two-sample MR, we found that asthma predicted by genome-wide association studies (GWAS)-identified SNPs is not associated with the risk of lung cancer. Different against evidence from observational studies, our mendelian randomization study provides evidence to suggest that asthma may not be causally associated with lung cancer.

Editorial acknowledgement

Clinical trial identification

Legal entity responsible for the study

Huaqiang Zhou.

Funding

National Key R&D Program of China (2016YFC0905500).

Disclosure

All authors have declared no conflicts of interest.