engleski

Myofibroblasts in invasive and in situ urothelial carcinoma of the bladder

Invasive carcinomas are usually accompanied with stromal response in which myofibroblasts may have an important role. Such a reaction may not be present in in situ carcinomas that are in majority of cases associated with lymphocytic reaction. The aim of this study was to analyze the presence and quantity of myofibroblasts in in situ and invasive urothelial carcinoma of the bladder. Urological pathology registry at the Ljudevit Jurak University Department of Pathology was canvassed for patients with both, in situ and invasive urothelial carcinoma. Relevant patient data including age, sex, tumor grade and stage of the disease were analyzed. All cases were examined by routine histology. In this study we analyzed the expression of alpha smooth muscle actin and vimentin as imunohistochemical markers for myofibroblasts. The intensity of reaction was graded semiquantitatively and expresssed as (-) for negative, (+) for weak staining, (++) for moderate and (+++) for strong staining. In the period from 1998-2002 there were 1243 biopsies with the diagnosis of urothelial carcinoma. Thirty-three biopsies with urothelial carcinoma in situ were found. We identified 10 patients with both in situ and invasive carcinoma. All of them were males ranging in age from 61-77 years (mean age 70.2 years). Imunohistochemical analysis revealed that in cases of invasive urothelial carcinoma reactive stromal cells are alpha smooth muscle actins positive indicating the myofibroblast phenotype. In areas with in situ carcinoma the intensity of SMA reaction was moderate in 3 cases, weak in 5 cases and negative in 2 cases and intensity of vimentin reaction was strong in 2 cases, moderate in 7 cases and weak in 1 case. In areas with invasive carcinoma the intensity of SMA reaction was strong in 5 cases and mild in 5 cases and intensity of vimentin reaction was strong in all of 10 cases. We found that the expression of myofibroblastic markers was strong in stroma of invasive carcinoma but absent or weak in in situ urothelial carcinoma. This finding may indicate a role of myofibroblasts in the stromal reaction to invasion but may also be useful in diagnosis of in situ versus invasive urothelial carcinoma. Further studies on larger groups of tumors are certainly needed.

myofibroblasts; urothelial carcinoma; bladder

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