Background: CD44 is an adhesion molecule and represents a highly varia
ble family of isoforms. The isoform CD44v6 has been associated with me
tastasis formation and poor prognosis in animal models and human colon
cancer. Results off studies in primary breast cancer are relatively s
mall and contradictory, Patients and methods. The immunohistochemical
expression of CD44v6 was studied in a series of 338 patients with prim
ary breast tumours, uniformly staged and treated in a single center wi
th a long median follow-up of 128 months. The prognostic significance
of CD44v6 as well as the correlation with several clinicopathological
features were analysed, Results. Two hundred nineteen of 338 (64.8%) o
f the breast cancers were CD44v6-positive (>5% of tumour cells with po
sitive staining), CD44v6 expression had no value for prog nosticating
disease-free or overall survival at this or any other cut-off point, C
onclusion. CD44v6 expression is not a prognostic factor in primary bre
ast cancer.