Expression of CD44 in uterine cervical squamous neoplasia: a predictor of microinvasion?

Objective: CD44, an integral membrane glycoprotein, may have an important role in early tumorigenesis, specifically, facilitating early tumor progression. Reports of the expression of CD44 in early uterine cervical squamous carcinogenesis are conflicting. We examined the expression of CD44 in microinvasive carcinoma of the cervix (MIC), as yet unreported, and compared it to that in cervical intraepithelial neoplasia (CIN) 1 and CIN 3 to further elucidate its role in early squamous carcinogenesis.

Methods: Seventeen cases of CIN 1, 24 cases of CIN 3, and 20 cases of MIC were stained with antibodies to CD44s, CD44v5, and CD44v6. Only membranous staining was considered positive.

Results: Positive membranous staining (>50% cells) was observed in 97% of cases of CIN 1 using all three antibodies. In CIN 3, positive staining was seen more often with CD44v6 (18/24) and CD44v5 (19/24) than with CD44s (6/24). Expression of CD44v6 was retained more often in MIC (16/20) compared with CD44s (3/20) and CD44v5 (9/20). Those cases of CIN 3 and MIC that failed to meet our criteria for positive staining showed either heterogeneous or absent staining.

Conclusion: There is a qualitative and quantitative reduction in expression of CD44 in MIC and CIN 3 compared with CIN 1. Down-regulation of CD44 variants may occur later in neoplastic progression than CD44s. This pattern may reflect their important biological function in early progression by cervical cancer cells. Patchy and heterogeneous staining in more advanced lesions limits the usefulness of CD44 and its variants in the assessment of microinvasion.