ESTROGEN-RECEPTOR SPECIFIC (ER1D5) EPITOPE STABILITY IN PARAFFIN SECTIONS

Immunohistochemical staining for the estrogen receptor can be influenc ed by a variety of technical variables, including degradation of stain ing with storage of tissue sections on glass slides. The epitope of th e commercially available rat monoclonal antibody (H222, ER-ICA) has de monstrated a significant loss of immunoreactivity in tissue sections s tored for 8 weeks. The purpose of the present investigation was to det ermine if the ER1D5 antibody is associated with a similar loss of reac tivity. Tissue sections were stored on glass slides at room temperatur e for short (1-2 days) or long (>365 days) intervals prior to immunost aining with the ER1D5 antibody. Evaluation of immunostaining was perfo rmed by manual (microscopic assessment) and automated (image cytometry ) methods. No difference in the intensity of the ER1D5 immunoreaction or the number of cells staining was observed by visual inspec tion. Al though the mean summed optical density of ER1D5 staining was less in s ections stored for long intervals relative to short intervals, this di fference was not statistically significant. These results suggest that the ER1D5 antibody is suitable for staining tissue sections stored on glass slides at room temperature for as long as 1 year.