Time-dependent biological differences in molecular markers of high-grade urothelial cancer over 7 decades (ras proteins, pTEN, uPAR, PAI-1 and MMP-9)

Abstract

The aim of this study was to evaluate changes and correlations between various molecular markers related to growth regulation and invasiveness in urothelial carcinomas in samples collected from 1932 to 2004. Paraffin-embedded autopsy/biopsy tissues from 144 patients were stained with antibodies against H-K-N ras proteins, pTEN protein, urokinase plasminogen activator receptor (uPAR), plasminogen activator inhibitor-1 (PAI-1) and matrix metalloproteinase-9 (MMP-9) and analyzed by in situ hybridization. Statistical analysis was performed by SPSS using cross tabulation and logistic regression. While the presence of K-ras, N-ras, PAI-1, and loss of pTEN increased over the last few decades, uPAR expression decreased during the same period. The increase in K-ras expression associated positively with the increase in expression of the other two ras proteins, H-ras and N-ras, and the loss of pTEN. A strong positive correlation was also observed between PAI-1 and uPAR, PAI-1 and previously detected markers, EGFR (epidermal growth factor receptor) and p53. Presence of uPAR was found to be positively associated with p16 expression. Multivariate analysis with clinical parameters revealed a positive correlation between PAI-1 expression and tumour grade, CkHMW (high molecular weight cytokeratin) and tumour grade, CkHMW and metastasis, EGFR and metastasis. mRNA could be detected in samples from the last 50 years while older samples were negative, indicating its complete degradation during longer storage. In conclusion, increased accumulation of K-ras, N-ras, and PAI-1 together with loss of pTEN in bladder carcinomas of grades II and III seems to be more dominant in recent times, suggesting an altered malignant potential in these neoplasms.