To determine whether the expression of the matrix protein tenascin (TN) is of diagnostic or prognostic value in cervical intraepithelial neoplasia (CIN).
Tenascin expression was evaluated in 75 formalin-fixed, paraffin-embedded biopsy and surgical specimens of the uterine cervix. Specimens included 15 low-grade squamous neoplastic lesions (CIN I), 30 high-grade squamous neoplastic lesions (CIN II and CIN III), 5 microinvasive carcinomas, and 15 invasive squamous carcinomas. Five normal cervices and 5 examples of cervicitis were used as controls. Expression of TN was studied by immunohistochemistry with a monoclonal mouse anti-human tenascin antibody. Tenascin expression in the basement membrane and in the stroma was arbitrarily graded as normal or slightly, moderately, or markedly increased.
In the normal cervix, TN formed a thin band along the basement membrane of the squamous epithelium, except for the transformation zone, where the bands splintered and delicate TN fibers were present in the adjacent stroma. In cervicitis, TN bands were splintered in the basement membrane and the protein was weakly expressed in the stroma infiltrated by inflammatory cells. In the 45 CIN lesions, regardless of grade, the TN bands in the basement membrane were slightly (25 cases) or moderately (20 cases) increased. In CIN lesions with chronic stromal inflammation, a slight increase in stromal staining was observed, similar to the findings in cervicitis. In microinvasive and frankly invasive squamous cell carcinomas, TN expression was markedly increased in the basement membrane and in the stroma surrounding the invasive nests of cancer cells.
Tenascin expression may be of value in the assessment of early stromal invasion in cancer of the uterine cervix. Tenascin expression is of no value in distinguishing various grades of CIN and, therefore, is not a predictor of future behavior.