Decrease of E-cadherin expression in canine cutaneous histiocytoma appears to be related to its spontaneous regression

Canine cutaneous histiocytoma (CCH) is an epidermotropic tumour of Langerhans cells, most frequent in young dogs, which undergoes spontaneous regression.

E-cadherin immunoexpression was analysed in ninety-three CCH, categorized according to Cockerell and Slauson (1976) criteria into four histological groups, representing different stages of tumour regression.

All tumours expressed membranous E-cadherin both in keratinocytes, and in tumoural cells and no differences were noted among the histological groups analysed. However, the intensity of the E-cadherin immunolabeling decreased in the presence of lymphoid infiltration and varied significantly among the groups considered (p<0.0001).

This study strongly suggests a down-regulation of E-cadherin expression in CCH pathogenesis and progression. The loss of E-cadherin expression might represent an activation/ maturation process of the tumoural cells constituting a switch for CCH regression.