Splice variants of CD44 in human cervical cancer stage IB to IIB

Aberrant expression of the cell adhesion molecule CD44 has been detected in human tumors and the expression of specific CD44 isoforms (splice variants) has been shown to be associated with metastasis and poor prognosis in human malignancies. We used three different variant exon sequence-specific murine monoclonal antibodies to epitopes encoded by exon v5, exon v6, or exon v7-v8 of human variant CD44 to study the expression of CD44 splice variants by immunohistochemistry in human cervical cancer. One-hundred five patients with surgically treated squamous cell carcinomas of the cervix stages IB to IIB were included in the study. CD44 splice variants CD44v5, CD44v6, and CD44v7-8 were detected in 70, 67, and 26%, respectively. Tumors expressing exon v6 had significantly more often metastasized to the pelvic nodes (58 vs 79%, P = 0.04). Expression of exon v6 was significantly correlated with a greater probability of vascular space invasion (73 vs 50%, P = 0.04) and a significantly lower rate of inflammatory stromal reaction (48 vs 78%, P = 0.004). Patients suffering from tumors expressing splice variant CD44v6 showed poorer overall survival (P = 0.03). In cases with negative pelvic lymph nodes we found a poorer prognosis when tumors expressed CD44v6 (P = 0.01) or CD44v7-8 (P = 0.02). Among the investigated CD44 splice variants expression of exon v6 is the most promising prognostic marker in surgically treated cervical cancer.