Prognostic importance of the expression of CD44 splice variants in oral squamous cell carcinomas

Considering squamous cell carcinomas (SCCs) of the oral cavity and orophary nx the molecular mechanisms underlying the infiltration and destruction of adjacent tissue as well as the metastatic spread are largely unknown. In th is context, the detection of defective expression of cellular adhesion mole cules in the tumour cells, e.g. CD44, might be important and correlated wit h prognosis. Paraffin-embedded tumour-tissue from 99 patients with primary oral and oropharyngeal SCC, additionally including corresponding lymph-node metastases in nine cases, was analysed for expression of the CD44 splice v ariants v4, v5, v6, v7, and v9 by means of immunohistochemistry. A diminuti on of at least one of the examined CD44 isoforms compared to the normal ora l epithelium was observed in 39.4% of the squamous cell carcinomas. No corr elations could be found between CD44 expression and pT- or pN-stage. Howeve r, decreased expression of v9 was correlated with higher histological grade (p < 0.001). Moreover, reduced CD44 expression was a statistically signifi cant independent predictor for shorter survival time (p = 0.002) as well as shorter recurrence-free interval (p = 0.004) in addition to pT- and pN-sta ge. The separate analysis showed that particularly the decreased v7 (p = 0. 04) and v9 (p < 0.02) expression in the tumour cells was associated negativ ely with survival. (C) 1999 Elsevier Science Ltd. All rights reserved.