[Fibronectin in gastrointestinal tumors and its relation to biological characteristics of tumor].

Through immunohistochemical technique, distribution of FN in normal mucosa, benign and malignant tumors of human gastrointestinal tract were studied. In normal and adenoma tissues, FN was found in both basement membrane (BN) and interstitial tissue. While in cancer tissue, there was a consistent decrease of BM FN content around the tumor nests particularly more apparently in cases of invading carcinoma. Statistical analysis showed that the reduction of BM FN was correlated with the degree of tumor dedifferentiation but not with the incidence of regional metastases. No association was noticed between the stroma FN and tumor behaviors. Since small blood vessels were usually delineated clearly by the staining for FN, FN might be considered as a marker in identifying the invasion of blood vessel wall by tumor cells. It is suggested that lack of BM FN in tumor tissues might be mainly due to decrease of FN synthesis by the tumor cells.