CK7 is expressed in a majority of urothelial carcinomas. (CK7+/CK20+)  Bladder adenocarcinomas with intestinal differentiation may lose CK7 expression.

(++/-) Wide variation in reported expression (15-97%), but appears a majority are positive (CK7+/CK20+).  There is some evidence that CK20 may be helpful in CIS dx.  Reactive urothelium shows CK20 expression in the umbrella cells.  Most dysplasia/CIS cases show at least focal transmural CK20 expression.  Sensitivity and specificity for CK20 have been shown to be >70% and >90%, respectively.  (Ki-67. p53, & p16 may also be useful)

p63 staining is found in >90% of urothelial layer nuclei.  PSA combined with p63 may be a helpful combination to differentiate a primary prostate tumor from urothelial carcinoma.

34betaE12

CK5/6

HMWK which is expressed in the basal layer of prostate glands, and urothelium (highly sensitive).  Practically any tumor with squamous differentiation will usually express HMWKs.

p53

Expression found in 40-60% of bladder carcinomas (worse prognosis).  Expression of p53 in >50% of cells is seen in CIS, whereas reactive urothelium show weak patchy nuclear staining.

Increased expression in flat CIS and low grade tumors.

CD44

May be useful in that it is normally expressed in the basal layer, and is absent in full thickness CIS.

Often positive in urothelial dysplasia.