DEFB1 and cervical squamous intraepithelial neoplasia: Polymorphisms in the DEFB1 gene that encodes hBD-1 have been associated with increased susceptibility to HPV infection [24], whilst SLPI is known to have potent anti-viral activity against HPV in head and neck cancers [25] and is upregulated in CIN [26] and cervical cancer [27].