KRT7 and head and neck neoplasm: The most common histologic findings in SC include positive staining for cytokeratin 7, S-100, transcription factor SOX-10, vimentin, and mammaglobin and negative staining for transmembrane member 16A (DOG1), nuclear receptor subfamily 4 group A member 3 (NR4A3), P63, P40, and cytokeratin 5/6 [14] according to WHO Head and Neck Tumor Classification 5th Edition [17].