PER1 and neoplasm: To explore the effect of STK11 mutation on PER1 protein levels, we conducted the same K versus KL analysis in samples from the 2020 Clinical Proteomic Tumor Analysis Consortium (CPTAC) study, which includes proteomics data, (Gillette et al. 2020) and again found a significant increase (p = 0.0191) in PER1 protein levels in KRAS/STK11-mutant tumors (Fig. 1H).