Five of seven MAPS genes are upregulated in immortalized breast cancer cell lines compared to primary breast tumor cell cultures (CDC2, CDC20, CDKN3, MAD2L1 and RRM2) [34] and all seven MAPS genes are upregulated in response to infection of HPV-18, a virus associated with cervical cancer, in keratinocytes [35]. This evidence concerns the gene CDC20 and breast cancer.