The presence of aflatoxin B1-FAPY adduct and human papilloma virus in cervical smears from cancer patients in Mexico

Abstract

The carcinogenic biomarker aflatoxin B1-formamidopyrimidine 2,3-dihydro-2-(N-formyl)-2′,5′,6′-triamino-4′-4′-oxy-N-pyrimidyl-3-hydroxy-AFB1 called AFB1-FAPY adduct, and Human Papilloma Virus (HPV) types 16 and 18 were quantified from DNA cervical scrapes from 40 women with cervical cancer (CC) and 14 healthy women as controls. The relationship between the AFB1-FAPY adduct and HPV types 16 and 18 was determined. Competitive inhibitory indirect ELISA was validated with 94% inhibition to quantify the AFB1-FAPY adducts in picograms per milligram of DNA (limit of detection = 0.1 pg/mg, and limit of quantification = 10 pg/mg), polymerase chain reaction and DNA sequencing to identify HPV types. The average concentration of AFB1-FAPY adducts/mg DNA in the CC cases was 1025 pg, 1420 pg with HPV16 and 630 pg sharing HPV18 (p = 0.03). In comparison, healthy controls had ≤2.6 pg/mg DNA, a statistically significant difference (p = 0.00006). The presence of AFB1-FAPY adduct increased six-fold the risk for CC between cases and controls, the odds ratio was 6.1 (95% CI = 1.4–25.4). There was a close relationship between the AFB1-FAPY adducts and HPV16 in CC samples.