In contrast, the results of Silva-Figueroa et al.’s study from 2019 showed no statistical differences between the PC (61%), aPT (50%), and PA (40%) subgroups, but by combining the loss of E-cadherin expression with other biomarkers, such as Ki-67, parafibromin, galectin-3, and PGP9.5, the differential diagnosis of PC with non-malignant parathyroid tumors could be supported [73]. The gene discussed is CDH1; the disease is pachyonychia congenita.