CD44V6 EXPRESSION IS RELATED TO PROGRESSION IN RENAL EPITHELIAL TUMORS

Aims: Expression of CD44 variant isoform including exon 6 has been ass ociated to tumour progression in several carcinomas, However, no studi es have been performed to assess the prognostic value of the expressio n of this marker in renal cell tumours. Methods ann results: We studie d 58 renal cell tumours. All patients were followed up for at least 3 years after nephrectomy. Tumours were analysed for expression of CD44v 6 assessed by two isoform-specific monoclonal antibodies. RT-PCR was p erformed to detect CD44 variant transcripts in 10 cases in which immun ohistochemistry was negative, Twenty-two tumours showed reactivity in at least 1% cells for both antibodies with a strong membrane pattern, RT-PCR did not show CD44v6 transcripts in any of 10 studied tumours, I mmunohistochemical staining was more frequent in perivascular areas or in areas of vascular invasion. In fact, CD44v6 expression correlated well with nuclear grade (P=0.009), stage at diagnosis (P=0.04) and app earance of metastasis after nephrectomy (P=0.007), Although univariate survival analysis showed stage (P<0.001), grade (P=0.009) and CD44v6 expression (P=0.04) to be significant predictive factors, only stage r emained significant (P=0.0013) in the multivariate analysis. Conclusio ns: CD44v6 expression, assessed immunohistochemically, is related to t umour progression. However, its prognostic value in renal cell tumours is dependent on tumour stage at diagnosis.