PDGFRA and gastrointestinal stromal tumor: For example, TCs hyperplasia has been reported in inflammatory fibroid polyp neoplasia and platelet-derived growth factor receptor α (PDGFRα) mutant gastrointestinal stromal tumors (Ricci et al., 2018), and the number of TCs was found to decrease in basal cell carcinoma and squamous cell carcinoma (Mirancea et al., 2013; Smythies, 2015).