Carcinogenicity of Perfluoroalkyl Compounds

Abstract

This chapter reviews the information available on the carcinogenic potential of perfluoroalkyl acids in both animals and humans. Historically, perfluorooctanoic acid (PFOA) and perfluorooctanesulfonate (PFOS) have been the most widely used members of this chemical class making these the subject of the largest proportion of the reported studies. Caution needs to be exercised in projecting the biological activities of any of the chemicals in this family based on results from others. For example, considering the three chemicals for which lifetime studies in rats are available, the outcomes were different with no increase in tumors seen with perfluorohexanoic acid (PFHxA), liver adenomas seen with PFOS, and adenomas of the liver, testis, and pancreas seen with PFOA. Mechanistic studies suggest that the liver tumors seen with PFOA reflect the activation of PPARα while the mechanism for tumor formation in the testis and pancreas is less clear. Epidemiologic studies have been reported for several levels of population exposure. Limited evidence of associations with kidney and testicular cancer has been reported in studies among community members exposed to drinking water contaminated by PFOA. Studies in workers exposed to higher levels of both PFOA and PFOS have not shown consistent evidence for an association with any specific cancer type. Studies in populations exposed to low levels of PFOA and PFOS have shown equivocal results for a variety of cancers with no consistent associations. Based on the evidence reported to date, the prospect for developing a carcinogenic outcome following exposure to PFOA and PFOS is remote. For other perfluoroalkyl acids, there is not sufficient evidence regarding their potential carcinogenicity. It should be noted that human exposures to these chemicals is currently quite low and appears to be decreasing.