{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\n The pi class glutathione S‐transferase (GSTP1) is a multifunctional enzyme that plays a central role in cellular defense by catalyzing the conjugation of reduced glutathione to a wide variety of electrophilic, potentially toxic compounds—including environmental carcinogens and chemotherapeutic agents. Genetic studies have defined its allele frequencies in diverse populations ["}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": "]. As a key phase II detoxification enzyme, GSTP1 contributes significantly to the metabolism and elimination of xenobiotics; its activity has been linked to differential responses to chemotherapy, for example, influencing overall survival in patients with advanced colorectal cancer ["}, {"type": "fg", "children": [{"type": "fg_f", "ref": "2"}]}, {"type": "t", "text": "]. In addition, its abundant expression in the blood–brain barrier supports its role in protecting neural tissues against toxic insults ["}, {"type": "fg", "children": [{"type": "fg_f", "ref": "3"}]}, {"type": "t", "text": "]. Furthermore, polymorphisms in the GSTP1 gene—such as the Ile105Val variant—modulate enzyme activity and have been associated with altered risks of therapy‐related malignancies as well as neurotoxicity from platinum‐based chemotherapeutics ["}, {"type": "fg", "children": [{"type": "fg_f", "ref": "4"}]}, {"type": "t", "text": "]. Beyond its classical detoxification functions, GSTP1 can serve other roles: for instance, in the human macula it acts as a high‐affinity xanthophyll-binding protein, selectively interacting with zeaxanthin to mediate carotenoid uptake and stabilization ["}, {"type": "fg", "children": [{"type": "fg_f", "ref": "6"}]}, {"type": "t", "text": "]. In prostate tissue, early and frequent CpG island hypermethylation leads to the epigenetic silencing of GSTP1—a loss that compromises the cell’s “caretaker” defense against oxidative and electrophilic stress and is implicated in carcinogenesis; importantly, pharmacological reversal of this methylation can restore GSTP1 expression ["}, {"type": "fg", "children": [{"type": "fg_f", "ref": "7"}]}, {"type": "t", "text": "]. Finally, GSTP1 also appears to modulate inflammatory processes, as specific genotypes—particularly in combination with other GST variants—alter the extent of allergic responses to environmental pollutants ["}, {"type": "fg", "children": [{"type": "fg_f", "ref": "9"}]}, {"type": "t", "text": "]. Overall, GSTP1 functions not only as a critical enzyme in detoxification and antioxidant defense but also as a modulator of drug response, ocular health, and inflammation, thereby influencing both disease susceptibility and therapeutic outcomes.\n "}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "S Garte, L Gaspari, A K Alexandrie, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Metabolic gene polymorphism frequencies in control populations."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Cancer Epidemiol Biomarkers Prev (2001)"}]}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "11751440"}], "href": "https://pubmed.ncbi.nlm.nih.gov/11751440"}]}, {"type": "r", "ref": 2, "children": [{"type": "t", "text": "Jan Stoehlmacher, David J Park, Wu Zhang, et al. 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