IL1B and cervical squamous intraepithelial neoplasia: Likewise, no difference in frequency of the −511C/T IL1B and the +3953C/T IL1B SNP or the variable number tandem repeat (VNTR) in intron 2 of IL-1Ra gene (IL1RN) was detected in CIN patients, [95] although these polymorphisms have been associated with IL1B gene expression and increased IL-1β production [96, 97].