RESUMEN
This immunohistochemical study has examined the degree and pattern of expression of a recently identified cytokeratin [CK-20] in 10 cases of normal bladder urothelium and 15 cases of TCC with well documented clinical course, using immunoperoxidase technique. In normal urothelium the expression of CK-20 was found to be differentiation related and confined to the superficial highly differentiated "umbrella" cells. Correlation of the expression of CK-20 with the clinical course in TCC of the bladder revealed that 85.71 of superficial bladder tumour with good outcome had retained a high degree of expression of CK-20: in the surface cell layer, whereas 80% of muscle invasive tumours, with aggressive clinical course, showed negative expression of the antigen. These observations suggest that the degree and pattern of expression of CK-20 is parallel to the outcome of the tunour. which may make CK-20 a useful prognositc marker in TCC of the bladder. There was another group which showed heterogenous pattern of expression of CK-20. This group was represented mainly by 3 cases of T1 tunours and who had one or more recurrences during the period of follow-up