PKP1 and esophageal cancer: Confusingly, upregulation of several desmosomal components, including DSG2, DSG3, PKP3, and PKP1, was observed in the development of various human cancers, including skin cancer, lung cancer, head and neck cancer, prostate cancer, colon cancer, cervical cancer, breast cancer, and esophagus cancer, often correlating with accelerated proliferation, increased metastasis or poor prognosis of tumors [23,24,25,26,27,28,29,30,31,32].