JC1 detects a nuclear antigen, distinct from Ki67, present in proliferating cells. It is useful as a marker of proliferation in cases such as squamous cell carcinoma where the Ki67 index cannot be determined. 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.