PER1 and colorectal cancer: Studies have also highlighted the association between VNTR or SNPs polymorphism in the PER gene family and an increased risk of certain cancers, such as breast cancer (Fores-Martos et al., 2021; Song et al., 2023), colorectal cancer (Holipah and Kuroda, 2020), and prostate cancer (Wendeu-Foyet et al., 2019; Hinoura et al., 2021), through the analysis of tumor tissues or patient blood samples.