CD44v6 expression in squamous cell carcinomas of the lung

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9688 Background: CD44v6 is a variant isoform of CD44 involved in the metastatic process of some malignant tumors. We want to study its expression in squamous cell carcinomas of the lung and its correlations with other clinical and biological parameters. Methods: The study group included 95 patients having squamous cell carcinomas of the lung. CD44v6 levels were dossified using an EIA (Bender Diagnostics. Austria) in the cell surfaces. The cut off for positivity was established in 5 ng/mg prot. Likewise we determined the concentrations of EGFR and erbB2/neu oncoprotein in cell surfaces. All results were expressed per mg of protein. Clinical stage, histological grade, ploidy and S-phase were taken into account. Results: In squamous cell carcinomas CD44v6 positivity was observed in 76 cases (80%) and it was similar to that noted in 38 normal lung tissues obtained from the same patients (86.8%).Nevertheless, CD44v6 concentrations were higher (p<0.001) than those observed in normal lung tissues (r: 5.1–1305, median 68.2 vs r: 8.6–100; median 32.3 ng/mg prot.) from the same patients. CD44v6-positive tumors had higher concentrations of EGFR (r: 3.1–325, median 38,7 vs r: 1–394, median 21.3 fmol/mg prot,; p:0,007), erbB2 oncoprotein (r: 219–77895, median 1868 vs r: 246-7848, median 1532 NHI/mg prot.; p:0,056) and global values of S-phase (r: 1.2–51.8, median 16 vs r: 1.8–28.9, median 9.9%; p:0,011) than CD44v6-negative tumors. Likewise, they were more frequently (p: 0,041) S-phase positive (>15.4%, which corresponds to the median for the entire tumor group studied). Conclusions: Our results led us to the following conclusions: 1) In squamous cell lung cancers CD44v6 expression is high and similar to that observed in normal pulmonary tissue obtained from the same patients; nevertheless, the CD44v6 concentrations are higher in those tumors than in normal lung tissues from the same patients 2) Its association with high EGFR and erbB2 oncoprotein levels, as well as, with high S-phase values suggests that it could be an indicator of a poorer outcome and progression in this subtype of lung carcinomas. No significant financial relationships to disclose.