Fig. 1

CD171 is expressed in retinoblastomas and cell lines derived from retinoblastomas. a The tumor is composed of small undifferentiated, blue cells (hematoxylin & eosin stain). Flexner-Wintersteiner rosettes may be found and are highly characteristic (arrows). The expression of CD171 was classified as negative or positive. (Scale bar: 50 μm). b CD3⁺-staining is exemplarily shown for patient 1 and patient 5. CD3⁺ infiltration in 6 of 30 randomly chosen primary retinoblastoma tumor samples. c CD171 cell surface expression on eleven established retinoblastoma cell lines detected with antihuman fluorochrome-conjugated CD171 antibody (n = 3). d Number of CD171 molecules per cell calculated based on a PE-bead based assay for three selected cell lines, WERI-Rb1, RBL15 and RB355 (mean ± SD, n = 3)