TMPRSS2 and lung adenocarcinoma: We observed similar fold increases with ΔH69/V70 in a range of other target cells in the context of overexpression of ACE2/TMPRSS2 (HEK293T cells transiently transfected with ACE2, or ACE2 and TMPRSS2 and A549 lung cells stably expressing ACE2 and TMPRSS2; Rihn et al., 2021) or endogenous levels of receptors in Calu-3 lung adenocarcinoma cells (Figure 3A).