title: Estrogen receptor measurement in breast cancer samples--importance of continuous storage of specimens in liquid nitrogen until assay.
mesh_terms: D001943:Breast Neoplasms / Q000032:analysis*; D005260:Female; D005615:Freezing; D006801:Humans; D011309:Preservation, Biological / Q000379:methods*; D011960:Receptors, Estrogen / Q000032:analysis*
chemical_list: D011960:Receptors, Estrogen