Abstract
Indigenous people living in the Bolivian Andes are exposed through their drinking water to inorganic arsenic, a potent carcinogen. However, the health consequences of arsenic exposure in this region are unknown. The aim of this study was to evaluate associations between arsenic exposure and changes in cancer-related proteins in indigenous women (n = 176) from communities around the Andean Lake Poopó, Bolivia. Arsenic exposure was assessed in whole blood (B-As) and urine (as the sum of arsenic metabolites, U-As) by inductively coupled plasma-mass spectrometry (ICP-MS). Cancer-related proteins (N = 92) were measured in urine using the proximity extension assay. The median B-As concentration was 2.1 (range 0.60–9.1) ng/g, and U-As concentration was 67 (12–399) μg/L. Using linear regression models adjusted for age, urinary osmolality, and urinary leukocytes, we identified associations between B-As and four putative cancer-related proteins: FASLG, SEZ6L, LYPD3, and TFPI2. Increasing B-As concentrations were associated with lower protein expression of SEZ6L, LYPD3, and TFPI2, and with higher expression of FASLG in urine (no association was statistically significant after correcting for multiple comparisons). The associations were similar across groups with different arsenic metabolism efficiency, a susceptibility factor for arsenic toxicity. In conclusion, arsenic exposure in this region was associated with changes in the expression of some cancer-related proteins in urine. Future research is warranted to understand if these proteins could serve as valid biomarkers for arsenic-related toxicity.
Highlights
Inorganic arsenic is classified as a class I human carcinogen [1]
In the Bolivian Andes, we have shown that women living around Lake Poopó are exposed to Inorganic arsenic (iAs) [15]
We identified four proteins (FASLG, SEZ6L, LYPD3, and TFPI2) measured in urine that were associated with B-As in indigenous
Summary
Inorganic arsenic (iAs) is classified as a class I human carcinogen [1]. Chronic exposure to iAs has been associated with multiple types of cancer, including cancers of the skin, lung, bladder, kidney, liver, and prostate [1,2,3,4]. Exposure to iAs has been associated with non-carcinogenic health effects such as cardiovascular disease, diabetes, and immunotoxicity [4,5,6]. Leakage of iAs from volcanic bedrocks into groundwater used as drinking water is one of the main contributors to human exposure, especially in Latin America where more than 14 countries present elevated iAs in drinking water [7]. Arsenic-related cancer has been evaluated in some Latin American countries, mainly Chile, Argentina, and Mexico [6].
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