Identification of "tumor-associated" nucleolar antigens in human urothelial cancer

Nucleoli isolated from HeLa S3 cells were used to produce rabbit antisera capable of binding nucleoli of transitional cell carcinomas (TCCa) of the bladder. Cross-reactivity of the rabbit antiserum with normal nucleoli was reduced by absorption with fetal calf serum, normal human serum, and human placental nucleoli. This antinucleolar antiserum exhibited strong reactivity in immunoperoxidase assays performed on specimens of human bladder cancer. In frozen tissue sections of 24 patients with TCCa and eight individuals without tumor, nucleolar staining was observed in all malignant specimens, but was not observed in seven of the normal specimens. Cytologic examination of bladder washing specimens from 47 normal individuals showed absence of nucleolar staining in 43 (91%) of 47 normal specimens while 12 (86%) of 14 specimens from patients with TCCa were positive. These results suggest that there are antigens associated with the nucleoli of HeLa cells and transitional cell carcinomas which are generally absent (or in low concentration) in normal human urothelial cells, and that antisera to these antigens may be useful in the cytologic diagnosis of human transitional cell carcinoma.