Interestingly, brigatinib treatment promoted classic ER signaling protein markers (including PERK, p-PERK, IRE1α, p-IRE1α and CHOP) in ALK-negative cancer cell lines (A549, Hep3B and Du145) (Figure S3A), but not in ALK-positive cancer cells (H3122 and H2228) (Figure S3B). This evidence concerns the gene DDIT3 and cancer.