Analysis of The Cancer Genome Atlas (TCGA) database showed that PNPase (PNPT1) gene expression was up-regulated significantly in a subset of lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC) lines (Fig S9) (Momcilovic et al, 2018). Here, PNPT1 is linked to squamous cell lung carcinoma.