Flow cytometry and FACS analyses of different populations of LB cells. LBN (A), LB45 (B), selected LB45-LUDSN11 (C), and a mixture of LB45/LB45-LUDSN11 (80/20) (D) cells were analyzed by flow cytometry using a UV light excitation to characterize porphyrin fluorescence in the cells. FACS analysis was then performed on mixed cells. After sorting, the cell populations corresponding to high (E) and low fluorescence (F) were reanalyzed.