Gene expression of matrix metalloproteinase-1 (interstitial collagenase) and matrix metalloproteinase-3 (stromelysin-1) in basal cell carcinoma by in situ hybridization using chondroitin ABC lyase

The gene expression of matrix metalloproteinase-1 and -3 was examined in basal cell carcinomas by in situ hybridization using digoxigenin-labelled riboprobes. Nodulo-ulcerative basal cell carcinomas demonstrated the gene expression for both metalloproteinases but superficial basal cell carcinomas did not present any transcripts for them. Transcripts for matrix metalloproteinase-1 (interstitial collagenase) were demonstrated densely in stromal cells among tumour masses, and those for matrix metalloproteinase-3 (stromelysin-1) were detected only in more advanced cases. Neither were expressed in tumour cells. The two metalloproteinases were produced by stromal cells according to the tumour invasion process, in which various growth factors, cytokines and inflammatory factors, which could regulate gene expressions of matrix metalloproteinases, were involved. It was also found that hybridization signals were enhanced by treatment with chondroitin ABC lyase, which digested abundant glycosaminoglycans in basal cell carcinoma. The procedure for the digestion is simple, and appears to be of value for in situ hybridization studies on tissues containing large amounts of glycosaminoglycans.