Elevated Urinary 3-OH-BaP Levels and CYP1A1 Enzyme Activity in Pediatric Acute Lymphoblastic Leukemia: A Case-Control Study in a High-Pollution Region

Introduction: pollutants related to acute lymphoblastic leukemia (ALL) include polycyclic aromatic hydrocarbons (PAHs), such as the carcinogenic benzo[a]pyrene (BaP). Urinary 3-hydroxybenzo[a]pyrene (3-OH-BaP) is a key biomarker for BaP exposure. Benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide (BPDE-dG), the ultimate metabolite of BaP, correlates with CYP1A1 activity. However, the correlation with urinary 3-OH-BaP remains unexplored in ALL. Exploring the relationship between urinary 3-OH-BaP and CYP1A1 enzyme levels in ALL patients, the present study makes a valuable contribution to global research, addressing the lack of non-Western data on urinary PAH biomarkers in pediatric ALL. Method: this was a case-control study including 68 subjects (33 patients and 35 healthy controls). Urine was collected for 3-OH-BaP detection via HPLC, and isolate of peripheral blood mononuclear cell (PBMC) for CYP1A1 enzyme levels via an ELISA kit. Results: mean urinary 3-OH-BaP levels were 623 ± 463 ng/mL in ALL cases vs. 286 ± 155 ng/mL in controls (p = 0,000). Mean CYP1A1 levels were 0,4817 ± 0,17 ng/mL in ALL cases vs. 0,3018 ± 0,03 ng/mL in controls (p = 0,000). A positive correlation was found between urinary 3-OH-BaP and PBMC CYP1A1 levels (r = 0,417, p < 0,001). Conclusion: the association between elevated urinary 3-OH-BaP and PBMC CYP1A1 levels in ALL patients compared to healthy controls suggests a role of CYP1A1 in BaP detoxification during carcinogenesis in pollution-exposed children.