PIK3R1 and neoplasm: Also included were xenobiotic metabolism genes, known to be regulated by the AHR, and several tumor suppressor and other genes involved in the onset or progression of proliferative diseases, such as Pten, Foxo3a, Cyr61, Prox1, and Pik3r1. [see Supplemental Material, Table 1 (http://www.ehponline.org/members/0800485/suppl.pdf) for the Entrez identification and accession number of all genes mentioned in this article].