We have reported that either depletion of endogenous ERK3 or exogenous overexpression of ERK3 did not show a significant effect on cell proliferation of H1299 and A549, at least under 2D culture conditions (Long et al., 2012; Elkhadragy et al., 2018), whereas other studies reported a role for ERK3 in promoting lung cancer cell proliferation (Bogucka et al., 2021; Cai et al., 2021). Here, MAPK6 is linked to lung cancer.