In addition, several other genes that have previously been associated with the DNA damage response showed elevated expression levels in the BPS-TA kidneys, including Brca1, Top2a, Cdkn2b, and Rad51. Collectively, these results suggest activation of the immune system and the DNA damage response as potential tumor suppressive mechanisms in the kidneys of BPS-TA mice. This evidence concerns the gene CDKN2B and neoplasm.