Prognostic value of keratin subtyping in transitional cell carcinoma of the upper urinary tract

To investigate the prognostic value of keratin subtyping in invasive transitional cell carcinomas (TCCs), we performed a systematic study applying 15 different monoclonal keratin antibodies on 53 upper urinary tract TCCs using a tissue microarray technique. Immunoreactivity was correlated with pT stages and tumour grades using the Fisher's exact test. Impact on disease-free survival was analysed using the Kaplan-Meier method and compared by the log-rank test. Immunoreactivity for keratins 5/6, 6, 7, 8, 13, 14, 17, 18, 19, 20, low molecular weight (LMW) keratins (8, 18) and high molecular weight (HMW) keratins (1, 5, 10, 14) was detected in varying quantities. Regarding semi-quantitative assessment, a prognostic impact was found for keratins 5/6, 7, 8, 13, 17, 20 and HMW keratins, with reduced expression or loss of immunoreactivity being significantly associated with disease progression. With respect to analysis of staining patterns, the retention of a basally accentuated labelling for keratin 5/6 and HMW keratin as well as a superficially accentuated labelling for keratin 20 was significantly associated with a favourable outcome. In conclusion, this investigation is the first to demonstrate a possible prognostic value for keratin subtyping in invasive (upper urinary tract) TCCs with respect to metastasis-free survival. Further studies, however, are needed to substantiate our results.