GPC4 and head and neck squamous cell carcinoma: Moreover, GPC4 expression was found to be significantly downregulated in pheochromocytoma and paraganglioma (PCPG), kidney chromophobe (KICH), kidney renal clear cell carcinoma (KIRIC), cervical and endocervical carcinoma (CESC), bladder carcinoma (BLCA), lung squamous cell carcinoma (LUSC), and head and neck squamous cell carcinoma (HNSC) in comparison to healthy tissues (Figure 1, negative change in GPC4 expression above the p value threshold of 0.05).