This document discusses various immunohistochemical markers used in lymph node pathology. It lists markers such as AE-1/AE3, CAM5.2, CK7, CK20, Calretinin, EMA, HMB45, Inhibin, Melan A, Mucin, PIN4, PSA, S100, SYN, and Vimentin that can help identify the primary site of cancers that have spread to lymph nodes.