Background: According to results of National Population-based Cancer Registry
Program, bladder cancer became the second after liver cancer among Egyptian males.
About 70% of bladder cancers are diagnosed as non-muscle invasive cancers with high
risk of recurrence beside the risk of progressing to muscularis propria invasion. The
challenge is to identify non –invasive cancers with reliable method for accurate
diagnosis as well as predicting the prognosis. Aim: We aimed to evaluate immunehisto-
chemical expression of Claudin-1and Claudin-4 in invasive and noninvasive
urothelial lesions and correlate them with clinico-pathological findings. Methods: This
retrospective study included 36 different cases of urinary bladder lesions designated as;
30 cases of urothelial carcinomas and 6 papillary urothelial neoplasms of low malignant
potential (PUNLMP) in addition to 6 normal control cases. Cases were graded
according to WHO classification and staged according to TNM pathological staging
system. Slides were subjected to Immuno-histochemical staining by claudin-1 and
claudin-4. Results: Claudin-1 had the highest level of expression among carcinoma
Value of Claudins in Papillary Urothelial Tumors
cases, while claudin -4 expression showed the highest expression among control cases
(p˂0.000 for both). Increased claudin-1 expression was significantly related to muscle
invasion (P=0.000), advanced T stage(P=0.000) and high tumor grade(P=0.012).
Claudin -4 expression showed significant statistical difference as regards urothelial
carcinomas without muscle invasion (P=0.000), earlier T stage and low tumor grade
(P=0.006). Conclusion: Claudin -1&4 could be used as potential markers to
differentiate invasive from non -invasive and LG from HG urothelial carcinoma. They
can predict the clinical outcome and take part in assessment of patients with UC.