A second recent study analyzed the genomic, transcriptomic, epigenetic, and immune profiling of mucinous breast cancer, showing that mucinous breast cancers were characterized by low genomic instability, decreased prevalence of PIK3CA mutations and low tumor infiltrating lymphocyte levels (lymphocyte infiltration in these tumors could be hindered by extracellular mucin acting as a barrier to immune recognition) [228]. The gene discussed is MUC5AC; the disease is neoplasm.