After outlier removal, significant heterogeneity was resolved for both the association between Cystatin D and lung adenocarcinoma (Q = 10.052, p = 0.122) and between cystatin M (prot‐a‐703) and squamous cell lung carcinoma (Q = 10.134, p = 0.256) (Table S5). Here, CST5 is linked to lung adenocarcinoma.