['Lymphovascular space invasion plays a critical role in the progression of cervical cancer and is an indicator of an unfavorable prognosis, even in patients with early-stage disease. Identification and functional characterization of molecules that are predominantly expressed in tumors able to penetrate lymphatic vessels may therefore help to improve the clinical assessment of cervical neoplasias with unclear prognosis. We used immunohistochemical staining to assess expression of the tetraspanin adapter protein CD9 in cervical tumors because inverse correlations with tumor invasiveness, ability to form metastases, and poor clinical outcome have been described for several other tumor types.'] Is progression of cervical carcinomas associated with down-regulation of CD9 but strong local re-expression at sites of transendothelial invasion?