EXPRESSION AND DEGENERATION OF TENASCIN-C IN HUMAN LUNG CANCERS

Tenascin-C is an extracellular matrix glycoprotein produced in respons e to epithelial-mesenchymal interactions during organogenesis and tiss ue remodelling. It has therefore been proposed as a stromal marker for epithelial malignancy. To test this hypothesis, 30 human lung cancers , presenting a variety of clinicopathological features, and six specim ens of normal tissue were examined by Western and Northern blotting of tenascin-C protein and mRNA. The results obtained were: (1) elevated tenascin-C expression was detected in all 30 cases by Western blotting , with mRNA increase in 22 of them; (2) mRNA for a large isoform of te nascin-C, including an alternatively spliced sequence, was expressed i n lung cancer tissues but not in normal lungs; and (3) metastasis to l ymph nodes was frequently found in cases whose tenascin-C was degraded into small fragments, These results suggest that tenascin-C degradati on can be used as a marker for metastatic potential of a tumour.