In addition, we observed that the monoallelic AMBRA1+/− cells apparently showed a higher proliferation rate than the wildtype cells, which is consistent with previous reports of increased tumorigenesis in monoallelic AMBRA1 mouse embryonic fibroblast cells [7], suggesting AMBRA1 as a haploinsufficient tumor suppressor, sensitive to the gene dosage. This evidence concerns the gene AMBRA1 and neoplasm.