SIGLEC1 and cancer: The presence of CD169+ macrophages in the tumor-draining lymph nodes (TDLNs) as well as within the tumor microenvironment, so-called CD169+ tumor-associated macrophages (TAMs) and their potential role in tumor development and tumor-specific immune responses have been investigated for a multitude of cancers, but represent a yet incompletely understood aspect of cancer immunology.