Healthy Mexicans Exposed to erionite: A Preliminary Study of Early-damage Biomarkers for Malignant Pleural Mesothelioma.

Background A rural community in Guanajuato State, Mexico, has presented a Malignant Pleural Mesothelioma (MPM) outbreak, one of the most rare and aggressive malignancies; such outbreak is associated with erionite exposure, a mineral responsible for the MPM epidemic in a Turkish village in the 1980’s. Erionite fibers are inhaled and deposited in the lungs, precluding biomonitoring its exposure in blood or urine. Methods Using a case-control study design, we recruited 40 children and 20 adults, residents of Tierra Blanca de Abajo, Guanajuato, México, where erionite exposure has been documented; they were considered as the exposed group. Besides, we recruited 40 children and 22 adults from the largest city of Guanajuato state, non-exposed to the mineral (control group); a main inclusion criterion for both groups were the absence of any type of cancer (current or former). Participants were paired by sex, age and occupation. In both groups we quantified mesothelin and osteopontin serum levels for comparison. Results In the adult exposed group, mesothelin levels were significantly higher compared to the adult control group (p = 0.003); mesothelin cut off value was: 17.92 ng/ml with 75% sensitivity and 68% specificity. Also, according to a multiple regression model where age, sex, wood smoke exposure, smoking habit, cancer family history and domestic asbestos exposure, were included, variable “residence place” was the only one showing a statistically significant association with serum mesothelin levels (β = 17.6, p = 0.005). Conclusions Mesothelin may be considered an early-damage biomarker for MPM, as well as an indirect endpoint for erionite exposure.