From Plastics to Prognosis: ANO4 Susceptibility Links Phthalate Exposure to Prostate Cancer Progression

Background/Objective: Di-2-ethylhexyl phthalate and its bioactive metabolite mono-2-ethylhexyl phthalate (MEHP) are ubiquitous endocrine-disrupting chemicals implicated in carcinogenesis. However, the molecular mechanisms linking MEHP exposure, host genetic susceptibility, and prostate cancer progression remain incompletely defined. Methods: We integrated transcriptomic profiling of MEHP-exposed human prostate epithelial cells with a genetic association study of 630 patients with prostate cancer receiving androgen deprivation therapy. MEHP-responsive genes were identified from public microarray datasets and subjected to pathway enrichment analyses. Germline single-nucleotide polymorphisms (SNPs) in MEHP-regulated genes were evaluated for their association with progression-free survival, overall survival, and cancer-specific survival. The clinical and functional relevance of the key genes was further assessed using large-scale public prostate cancer expression datasets. Results: MEHP exposure induced widespread transcriptional reprogramming, prominently suppressing focal adhesion and cell-matrix interaction pathways. Genetic analyses identified multiple prognostically relevant SNPs within MEHP-responsive genes, with anoctamin 4 (ANO4) variants showing consistent associations across all clinical endpoints. The minor allele of rs17485225 in ANO4 was significantly associated with reduced all-cause and prostate cancer-specific mortality. Pooled analyses revealed reduced ANO4 expression levels in prostate cancer tissues and improved survival in patients with high ANO4 expression levels. Pathway analyses linked low ANO4 expression levels with enhanced cell cycle activity and compromised cell adhesion. Conclusions: Our findings suggest that ANO4 may act as a mediator of MEHP-associated prostate cancer progression and support a gene-environment interaction model in which environmental toxicant exposure and germline variation converge on focal adhesion dysregulation to potentially contribute to aggressive disease.