Recently, independent studies have shown that the expression of two
integrin chains, beta 4 and alpha 2, plus the
epithelial cadherin are related to tumour progression in human bladder
carcinomas. For the first time, we compare the expression of these three
cell adhesion molecules using immunohistochemical analysis of consecutive cryosections from a series of 50
bladder tumors.
E-cadherin, beta 4, and alpha 2 were strongly expressed in normal urothelium. A majority of non-invasive
bladder cancers stained positively for
E-cadherin (62%), whereas only 29% expressed normal positivity for alpha 2, and only 35% for beta 4. However, most invasive tumours presented an aberrant expression of alpha 2 (81%), beta 4 (100%), and
E-cadherin (75%). We studied the correlation of immunoreactivity with histological grade and stage. The alpha 2 pattern was not correlated with stage and grade. In contrast, loss of normal beta 4 expression was significantly related to increasing tumour grade and deep invasion with a higher correlation for grade. Finally,
E-cadherin expression was highly correlated with stage, but not with grade. Thus our results indicate that, although many invasive bladder tumours presented a disorder in expression of the two
integrins alpha 2 and beta 4,
E-cadherin appeared to be a better market of invasiveness in bladder
carcinomas.