SEROLOGICAL EVALUATION OF SOLUBLE CD44 IN RENAL-CANCER

In this study, we examined the feasibility of using elevated serum CD4 4 concentration as an indicator in renal cancer. We performed enzyme-l inked immunosorbent assays using 63 sera obtained from 47 patients wit h renal cancer and 16 healthy controls and evaluated the clinico-patho logical parameters. The concentration of soluble CD44 standard (sCD44s td), indicating the concentration of all circulating CD44 isoforms, wa s significantly higher in renal cancer patients than in normal individ uals (745+/-170 ng/ml vs. 563+/-159 ng/ml, P=0.001). The concentration of soluble CD44 splice isoforms sharing exon v6 (sCD44v6) was also hi gher in the same patients (287+/-121 vs. 220+/-59, P=0.056). However, there were no correlations between the concentrations of sCD44std or s CD44v6 and clinicopathological parameters such as grade, stage, histol ogical type, tumor size and growth type. The ratio of sCD44std/sCD44v6 was higher in the rapid growth-type cancers than in the slow growth-t ype cancers (3.95+/-2.12 vs. 2.63+/-0.82, P=0.014). These findings sug gested that the serum concentration of unknown soluble CD44 isoforms n ot sharing exon v6, which are present in sCD44std, increases in patien ts with rapid growth-type cancers. These findings indicated that sCD44 std and sCD44v6 are not useful indicators of tumor burden and metastas is in patients with renal cancer, but that an unknown sCD44 isoform(s) plays a role in the biological behavior of the rapid growth-type canc ers.