Enzyme-linked-immunosorbent-assay for the detection of a novel 21-kda protein associated with the clinical course of patients with urogenital tumors.

A novel 21 kDa protein (p21) was detected in sera of patients with urogenital tumors by ELISA, using rabbit polyclonal antibodies generated against the p21 polypeptide. Eight out of 11 patients (72%) exhibited a 2-5 fold increase in pre-treatment p21 serum levels as compared with 20 healthy individuals. A decrease of p21 levels was observed in 6 out of 8 patients in which a regression of the disease was shown post-treatment. An increase or no change in p21 levels was observed in 3 patients with no change or progression of the disease. The ELISA described herein may be useful for clinical monitoring of patients with urogenital tumors, some of which have no available tumor marker.