GSTT2B (glutathione S-transferase theta 2B) is a Phase II detoxification enzyme that catalyzes the conjugation of reduced glutathione to hydrophobic electrophiles and exhibits sulfatase activity 1. The gene is subject to a high-frequency 38-kb deletion polymorphism that shows strong linkage disequilibrium with the neighboring GSTT1 deletion (D' = 0.841), with this deletion being the derived state compared to chimpanzees 2. The GSTT2B deletion significantly reduces GSTT2 mRNA expression, suggesting functional consequences for cellular detoxification capacity 2. GSTT2B plays important roles in oxidative stress management and cellular protection. In colon cancer, reduced GSTT2B expression contributes to decreased glutathione synthesis capacity, leading to elevated reactive oxygen species levels and genomic instability that enhances chemosensitivity 3. The protein has been identified as a potential therapeutic biomarker in multiple contexts: patients with GSTT2B deletions show better response to BCG immunotherapy in bladder cancer with fewer treatment cycles 4, and GSTT2B downregulation is associated with enhanced therapeutic effects of nasal turbinate stem cells in rheumatoid arthritis models 5. However, population studies have not found associations between GSTT2B copy number variants and complex diseases like asthma or Alzheimer's disease 6.