PTTG1 and cancer: Our in vitro and in vivo work (Davies, Arnason and Harkness, unpublished), and findings from others, have noted that many APCCDH1 mitotic substrate genes and proteins are elevated in cancer cells, including CDC20 [94], PLK1 [95], AURA/B [96,97], HURP (DLGAP gene [98]), Securin (PTTG1 gene [99]), and Geminin [100], hinting that impaired APC activity as a whole is involved, rather than isolated CDC20 elevation.