EXTENSIVE DEPOSITION OF BASEMENT-MEMBRANE BY TUMORS - A PROGNOSTIC FACTOR - A REAPPRAISAL

A loss of the continuous linear deposit of basement membrane around in vasive carcinomas has been suggested to correlate with their increased invasiveness. In contrast, extensive basement membrane deposition wou ld represent a more favourable prognosis. The Engelbreth-Holm-Swarm (E HS) tumour, a transplantable neoplasm, is widely used for its ability to synthesize and deposit large amounts of basement membrane component s. We have evaluated the metastatic potential of this neoplasm 2 month s after subcutaneous inoculation. Histological examination of lung sec tions revealed the presence of numerous metastatic foci. The metastati c cells retained their organization into clusters surrounded by extrac ellular matrix. Both the 72 kDa and the 92 kDa type IV collagenases we re detected by zymography in Triton or urea extract (matrigel) of prim ary tumour. These results cast doubt on the hypothesis that the extens iveness of basement membrane deposition might always be of prognostic value by being inversely correlated with the degree of invasiveness of a carcinoma.