Once attached to the FSMW, CTC are fixed to allow identification with fluorescence-labeled antibodies directed to cytokeratins and further fluorescent staining for other cellular biomarkers, such as HER2, estrogen/progesterone receptor, epidermal growth factor (EGF)-receptor, urokinase-type plasminogen activator (uPA)/plasminogen activator inhibitor type-1 (PAI-1), and other cancer biomarkers of interest. The gene discussed is PGR; the disease is cancer.