Background: Overexpression of alternatively spliced CD44 isoforms has been reported to correlate with poor prognosis in several human malignancies. To the authors' knowledge, there are no studies concerning the prognostic value of CD44 isoform overexpression in patients with squamous cell carcinoma of the vulva.
Methods: Thirty cases of squamous cell carcinoma of the vulva with International Federation of Gynecology and Obstetrics Stage I to III were examined immunohistochemically for overexpression of CD44 isoforms. We used 3 different variant exon sequence-specific murine monoclonal antibodies to CD44 isoforms containing variant exons v5, v6, and v7 to -8, respectively. The correlation of CD44 overexpression with clinical stage, histologic grade, and disease free and overall survival was investigated.
Results: CD44 isoforms CD44v5, CD44v6, and CD44v7-8 were detected in 83% (25/30), 63% (19/30), and 27% (8/30) of the tumor samples, respectively. Patients with tumors overexpressing CD44v6 showed a significantly shorter relapse free (log rank test, P = 0.002) and overall survival (log rank test, P = 0.003) compared with patients with tumors lacking CD44v6 overexpression. Expression of CD44v5 and CD44v7 to 8 had no impact on patients' survival. Clinical stage and histologic grade did not correlate with CD44 overexpression.
Conclusions: Immunohistochemically detected overexpression of CD44 isoforms containing variant exon v6 is correlated with a poor relapse free and overall survival in patients with carcinoma of the vulva.