We found that the average IHC score of GPRC5A is high in normal tissues (141.22 ± 66.975), whereas it was significantly lower in leukoplakia (76.00 ± 67.389), and greatly repressed in HNSCC (34.63 ± 41.389) (Fig. 1d). The gene discussed is GPRC5A; the disease is Oral leukoplakia.