Second, based on our data in Fig 3G that FXR1 binds to p21 as well as previous report showing association of FXR1 with G4 RNA structure in the 3'–UTR region p21 [26], we therefore probed the relationship between FXR1 and p21 in HNSCC. Here, CDKN1A is linked to head and neck squamous cell carcinoma.