RESUMO
OBJECTIVES: The LIM and SH3 (LASP)-1 protein is a focal adhesion protein that has been linked to oncogenesis. The aim of this study was to evaluate the diagnostic use of the detection of LASP-1 in tumor specimens and in urine for noninvasive detection of transitional cell carcinoma (TCC). MATERIALS AND METHODS: Immunohistochemical staining for LASP-1 was performed on 72 archived bladder tumor specimens, and LASP-1 content was measured in 132 spontaneous urine sample sediments by Western blot analysis. RESULTS: In the histologic specimens, immunohistochemical staining for LASP-1 showed abundant expression throughout the urothelium of the bladder and ureter. However, modest overexpression of LASP-1 was observed in the TCC specimens. Measurement of the LASP-1 protein concentrations in urinary cell pellets from healthy donors and bladder cancer patients was highly sensitive for the presence of TCC. The cut-off value was determined by receiver operating characteristic (ROC) analysis. When a cut-off value of 1 ng LASP-1/500 µl of urine was used, the sensitivity, specificity, and positive and negative predictive values of the assay were 83.1%, 85.3%, 83.1%, and 80.6%, respectively.The increased urinary LASP-1 content in TCC patients was attributable in part to a specific increase in cell shedding presumably caused by changes in cell adhesion, as confirmed by LASP-1 knockdown. Contamination with erythrocytes above 250 cells/µl and urinary infection gave false positive results and are therefore sample exclusion criteria. CONCLUSIONS: In the absence of urinary infection or gross hematuria, urinary LASP-1 level is a promising marker for transitional cell carcinoma.
