Prognostic value of immunohistochemically detected CD44 isoforms CD44v5, CD44v6 and CD44v7-8 in human breast cancer.

We investigated the expression of CD44 isoforms containing variant exons v5, v6 and v7-8 in 115 human breast cancer specimens by means of immunohistochemistry. CD44 isoforms CD44v5, CD44v6 and CD44v7-8 were detected in 56% (n = 64), 24% (n = 28) and 15% (n = 17), respectively. In 36 specimens of axillary lymph node metastasis, expression of CD44v5, CD44v6 and CD44v7-8 was found in 94% (n = 34), 92% (n = 33) and 89% (n = 32), respectively. Five year survival rates with or without CD44v5 and CD44v6 expression were 71% versus 86% (log-rank test, P = 0.02) and 62% versus 81% (log-rank test, P = 0.001), respectively. For disease-free survival, expression of CD44v5, CD44v6 and CD44v7-8 showed a prognostic impact (log-rank test, P = 0.004, P = 0.0001 and P = 0.0001, respectively). However, multivariate analysis revealed that all investigated CD44 isoforms failed to be independent predictors of the patient's outcome.