We then performed in vitro proliferation assays using SAEC, HBEC, Calu-6, H841, H358, and A549 cells following constitutive overexpression or knockdown  of ZNFX1. Overexpression of ZNFX1 virtually abolished proliferation of SAEC and HBEC, as well as all four lung cancer lines (Fig. 5A). Here, ZNFX1 is linked to lung cancer.