Immunohistochemical and soluble expression of CD44 in primary and metastatic human prostate cancers.

Immunohistochemical expression of standard and v6 isoforms of CD44 was performed on specimens from three groups of prostate cancer patients: Group I, primary prostate cancers (N=31); Group II? lymph node metastases (N=18); and Group III, bone metastases (N=15). In addition, serum from all Group I patients was analyzed for soluble CD44 expression. Benign glands exhibited strong CD44s and CD44v6 expression in basal cells. Weak basolateral staining was identified in superficial luminal cells. Malignant glands and metastatic tumors revealed diminished or absent expression of both CD44s and CD44vG with a heterogeneous pattern. Pretreatment with chondroitinase did not significantly alter CD44 expression. Soluble CD44 was present in all serum samples, however, expression was variable. There was no statistically significant correlation between immunohistochemical CD44 expression, soluble CD44 expression, and clinical progression.