Investigating causal relationships between plasma proteins and lung adenocarcinoma: result from proteomics and Mendelian randomization study.

Background: Plasma proteins contribute to the identification, diagnosis, and prognosis of human illnesses, which may be conducive to understanding the molecular mechanism and diagnosis of Lung adenocarcinoma (LUAD).

Methods: We collected plasma samples from 28 healthy individuals (H) and 56 LUAD patients and analyzed them using LC-MS/MS-based proteomics to determine differential expression plasma proteins (DEPPs). Then, the DEPPs were subjected to a two-sample Mendelian randomization (MR) study based on an "Inverse variance weighted (IVW)" approach to investigate the causal relationships between DEPPs and LUAD. Logistic regression analysis was conducted to develop a diagnostic model for LUAD.

Results: 317 plasma proteins were found in proteomics, and 19 DEPPs were identified. The MR study revealed that IL20RB (odds ratio (OR) = 1.600, 95% Confidence Interval (CI) [1.098, 2.331], P = 0.014) and SAA2 (OR = 1.048, 95%CI [1.012, 1.081], P = 0.017) were highly related to LUAD. A diagnostic model was established with IL20RB and SAA2. The AUC of this diagnostic model was 0.858.

Conclusion: Plasma IL20RB and SAA2 levels were closely connected with LUAD.