CD274 and head and neck squamous cell carcinoma: LOC51089, also called C1QA, was found to be involved in the innate immune system and was associated with the expression of PD-L1 (Olkhov-Mitsel et al., 2020), and its abnormal expression in tumor tissues was confirmed in head and neck squamous cell carcinoma and clear cell renal cell carcinoma (Yu et al., 2019; Apanovich et al., 2020).