PTPA and neoplasm: Prior work has shown that RABL6A promotes tumor cell proliferation and survival through multiple factors, including p27-CDK-RB119,32,33 and PP2A-AKT-mTOR34 pathways with a role for Myc suggested by evidence that its mRNA and protein expression depend on RABL6A.32,35 As recently observed in human MPNSTs,19Nf1 mutant mouse MPNSTs lacking RABL6A displayed increased p27 expression compared to wildtype lesions (Figure 4A–B).