KRT7 and neoplasm: Immunohistochemical analysis disclosed positive staining to AE1/AE3, CK20, CK5/6, P40, c-kit and NCAM, and negative staining to CK-7, CK-8, AFP, GATA3, PSA, synaptophysin, and chromogranin A. Thus, the tumor of epithelial cell origin was confirmed through AE1/AE3 positive staining.