TMEM26 (transmembrane protein 26) is a plasma membrane-localized protein with context-dependent roles in cellular function and disease pathogenesis. As a beige adipose tissue marker 1, TMEM26 expression is elevated in fibro-fatty tissues associated with arrhythmogenic cardiomyopathy and correlates with thermogenic capacity in browning adipose tissue 23. TMEM26 is upregulated during white-to-brown adipose tissue transition in visceral adipose tissue proximal to colorectal tumors, suggesting involvement in metabolic remodeling 4. In epithelial tissues, TMEM26 functions as a pro-metastatic determinant in esophageal squamous cell carcinoma by disrupting tight junction protein assembly and activating NF-κB signaling to promote epithelial-mesenchymal transition 5. In breast cancer, TMEM26 exhibits dual, receptor-dependent functions: in estrogen receptor α (ERα)-positive tumors, it acts as a tumor suppressor by negatively regulating integrin β1 and reducing endocrine resistance risk 6. Conversely, high TMEM26 expression in ERα-negative/triple-negative breast cancer associates with increased recurrence risk, indicating oncogenic function in this context 6. Genetically, TMEM26 variants show interaction with excessive daytime sleepiness in sleep apnea pathogenesis 7, linking it to cardiometabolic complications. N-glycosylation regulates TMEM26 plasma membrane retention and functional expression 6.