Estrogen receptor antibody incubation time and extent of immunoreactivity in invasive carcinoma of the breast: the importance of optimizing antibody avidity.

We noticed that the percentage and intensity of estrogen receptor (ER) antibody (Ab) AB ER 1D5 immunohistochemical (IHC) staining was altered by Ab incubation time and the type of chromogen detection system in invasive breast carcinomas. We studied the impact of these 2 factors on Ab ER 1D5 immunoreactivity. Serial sections from 22 strongly ER-positive invasive breast carcinomas were immunohistochemically stained with Ab clone ER 1D5 using 3 IHC protocols.