BMAL2 (basic helix-loop-helix ARNT like 2) is a circadian clock transcription factor that forms heterodimers with CLOCK to regulate circadian gene expression and cellular metabolism 1. The protein contains a basic helix-loop-helix PAS domain and shows 49% identity to BMAL1, with tissue-specific expression in fetal brain and adult liver 2. BMAL2 functions as part of the positive limb of the circadian transcriptional feedback loop, activating E-box containing promoters and regulating metabolic processes 1. In metabolic contexts, BMAL2 controls adipose tissue inflammation and metabolic adaptation, with deletion leading to increased obesity, hepatic steatosis, and insulin resistance 3. The gene shows significant disease relevance, as polymorphisms are associated with type 2 diabetes risk in obese individuals 4 and breast cancer susceptibility 5. In cancer, BMAL2 promotes drug resistance and metastasis through multiple mechanisms: enhancing 5-fluorouracil resistance in colon cancer by upregulating SLC7A11 to suppress ferroptosis 6, promoting nasopharyngeal carcinoma invasiveness via the AMOTL2-LATS-YAP pathway 7, and driving acute myeloid leukemia cell proliferation through HIF1A-mediated aerobic glycolysis 8. Additionally, BMAL2 promotes macrophage endotoxin tolerance during sepsis through TREM-1-dependent mechanisms 1.