While PFOS appears to stimulate mouse and human PPAR receptors [42, 46] when screened in cell lines, robust in vivo evidence for direct PPAR receptor mediation is lacking, and human PPARα expression is considerably reduced compared to in rodents; if so, this may thus lessen the importance of this pathway in human familial adenomatous polyposis or acquired colorectal cancer [6]. The gene discussed is PPARA; the disease is Familial adenomatous polyposis.