Significant downregulation of the core circadian clock genes, CLOCK, BMAL1, PER1, CRY1, REV-ERBα, and RORα, was found in cervical cancer tissue specimens and in high-grade squamous intraepithelial lesions compared to the normal cervical epithelium [45]. This evidence concerns the gene NR1D1 and squamous cell intraepithelial neoplasia.