A possible explanation for this is the reciprocal regulation between PER1 and HIF1α (Chilov et al. 2001; Wu et al. 2017; Kobayashi et al. 2017; Hogenesch et al. 1998; Kelly et al. 2020), a potential role for HIF3α, or that hypoxia has context specific roles in molecular subsets of lung adenocarcinoma. Here, PER1 is linked to lung adenocarcinoma.