Herein, it is found that lncRNA AFAP1‐AS1 encodes a conserved 90‐amino acid peptide located on mitochondria, named lncRNA AFAP1‐AS1 translated mitochondrial‐localized peptide (ATMLP), and it is not the lncRNA but the peptide that promotes the malignancy of nonsmall cell lung cancer (NSCLC). This evidence concerns the gene PTGDR and lung cancer.