Expression of beta 1 integrin in relation to histological features in normal and neoplastic canine testicles

The expression of the beta 1 common chain of the VLA integrin subfamily was evaluated immunohistochemically in a series of five normal and 30 neoplast ic canine testicles. The tumours, consisting of seminomas or Sertoli cell t umours, were classified according to WHO criteria as intraductal without si gns of invasion, intraductal with signs of invasion, or diffuse. Expression of beta 1 integrin decreased progressively from intraductal tumours withou t signs of invasion, to the diffuse type, in which immunolabelling was gene rally absent. In a few cases of diffuse neoplasia, groups of neoplastic cel ls exhibited strong positivity that was not restricted to the basal pole of the cell membrane. These results suggest that the expression of beta 1 int egrin was related to the histological tumour type, possibly reflecting a sp ecific requirement for a reduction in integrin by neoplastic cells with inf iltrative and metastatic potential. (C) 2000 Harcourt Publishers Ltd.