Immunofluorescent staining of CK19 and ASMA in primary cultures of fibroblasts derived from breast cancers (BCF) and adjacent areas of normal breast from surgical specimens (NTF). BCF 016, BCF 037 and BCF 044 are derived from different patients, whereas NTF are matched normal tissue fibroblasts pooled from patients 037 and 044. Breast cancer cell line MDA-MB-231 was used as a positive control for CK19. Hoechst (blue) staining shows the nuclei. Original magnification of 400x. Bars represent 20 μm.