Also, a study of normal cervical tissues, high-grade squamous intraepithelial lesions (HSILs) and cervical cancer samples showed a significantly higher frequency of PIWIL1 protein expression in HSILs and cervical cancer tissues when compared with that in the normal cervical epithelium (Liu et al., 2014). Here, PIWIL1 is linked to squamous cell intraepithelial neoplasia.