High syndecan-1 expression is associated with favourable outcome in squamous cell lung carcinoma treated with radical surgery.

Expression of syndecan-1 is down-regulated in many cellular transformation models. We studied the clinical significance of syndecan-1 expression in 116 squamous cell lung carcinomas treated with radical surgery. Paraffin-embedded tissue samples were immunostained with two antibodies against human syndecan-1 (B-B4 and 104-9). Syndecan-1 expression was higher in well differentiated cancers than in moderately or poorly differentiated cancers with either antibody (P=0.001 for B-B4, and P<0.0001 for 104-9), but no significant association was found with the primary tumour size (T-stage) or the clinical stage. When the median expression (10% of cancer cells positive in B-B4 staining) was used as the cut-off value, cancers with high expression were associated with more favourable survival than those with low expression (the 2-year survival rate corrected for intercurrent deaths 84% vs 61%, P=0.026). However, syndecan-1 expression was not an independent prognostic factor in a multivariate survival analysis. We conclude that syndecan-1 expression decreases in parallel with histological dedifferentiation in squamous cell carcinoma of the lung, and that low syndecan-1 expression is associated with unfavourable outcome.