CDKN1A and cervical cancer: To further confirm the association between the p21 haplotype and the risk of cervical cancer, we selected the haplotypes of which the sum frequency in case and control is more than 5% and analyzed the association between the numbers of variants in each haplotype (ht1-AGT, ht2-CCC, ht3-CGC and ht4-CGT) and the risk of cervical cancer (Table3).