Per- and polyfluoroalkyl substance concentrations during pregnancy and at birth and risk of childhood acute lymphoblastic leukemia.

Background: Per- and polyfluoroalkyl substances (PFAS) comprise a class of persistent environmental pollutants with potential carcinogenic effects, but their impact on childhood cancer remains underexplored. A child's exposure to PFAS can occur through various pathways postnatally, including contaminated food, water, and consumer products; and in utero, as PFAS can cross the placenta.

Methods: To investigate the association between early-life PFAS exposure and the risk of childhood acute lymphoblastic leukemia (ALL), we analyzed archived blood samples from children diagnosed with ALL and matched cancer-free controls. Using novel untargeted liquid chromatography-high resolution mass spectrometry (LC-HRMS), we measured PFAS levels in paired maternal pregnancy and child newborn blood samples.

Results: Our study identified an independent association between MeFOSAA levels at birth and increased ALL risk, particularly among children diagnosed at 2 years of age or younger. MeFOSAA measured in maternal second-trimester blood showed a weak association with ALL, although it was not statistically significant.

Conclusions: These results suggest that early-life exposure to MeFOSAA may play a critical role in the development of childhood ALL. Our findings corroborate previous reports linking MeFOSAA exposure during pregnancy to childhood ALL, highlighting its potential carcinogenicity during key developmental windows.