This MAb is specific to progesterone receptor and shows minimal cross-reaction with other members of the family. Progesterone receptor is expressed as two major isoforms, PR-A (81 kDa) and PR-B (116 kDa) . Expression of PgR has been suggested to reflect a intact estrogen regulatory machinery and therefore, predict better clinical response to endocrine therapy than ER alone. It is excellent for immunohistochemical staining of formalin/paraffin tissues.Primary antibodies are available purified, or with a selection of fluorescent CF® Dyes and other labels. CF® Dyes offer exceptional brightness and photostability. Note: Conjugates of blue fluorescent dyes like CF®405S and CF®405M are not recommended for detecting low abundance targets, because blue dyes have lower fluorescence and can give higher non-specific background than other dye colors.