A recent metagenomic analysis on lung adenocarcinoma and the corresponding healthy tissues from patients showed that Aspergillus sydowii promotes the progression of lung adenocarcinoma by recruiting and activating myeloid-derived suppressor cells through IL-1β signaling, which is mediated by the β-glucan-triggered Dectin-1/CARD9 (caspase recruitment domain-containing protein 9) pathway (36). Here, CARD9 is linked to lung adenocarcinoma.