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C Clavel

Publications and source records attributed to C Clavel.

59 records · Page 4Linked to original sources
PubMed1988

[Breast carcinomas and the extracellular matrix].

This paper underlines the interrelations between tumoral cells and the extra-cellular matrix in breast cancers with possible applications for the diagnosis and the prognosis. In mammary carcinomas, the first step of tumoral invasion is characterized by the loss of basement membrane components, particularly type IV collagen and laminin. Immunohistochemical detection of these disruptions of basement membrane is easy and useful for the diagnosis of "in situ" or microinvasive carcinomas. Laminin seems also to facilitate the adhesion of cancer cells to type IV collagen, and the dosage of its fragment P1 in the blood serum may be a good marker for the follow up of the patients. Stromal reaction involves many intricate macromolecules of the extra-cellular matrix. Types I and III collagens are often present in non colloid carcinomas. Rate, turn over of elastin and its prognostic value are still debated. Elastosis is related to well differentiated carcinomas and the presence of estrogen receptors. The stroma of the colloid form of breast cancer is rich in proteoglycans. Malignant and stromal cells, through the intermediary of cytokines, can synthesize these macromolecules. Hyaluronic acid and chondroitin sulfate are abundant in mammary carcinomas and form a favorable substrate for the growth and the migration of malignant cells. However, proteases decrease and limit their action. The presence of fibronectin, principally in the stroma, is difficult to interpret but fibronectin seems to play a role in tumoral retraction.

Basement Membrane↗
PubMed1988

[Distribution of fibronectin and laminin during development of the human myenteric plexus and Hirschsprung's disease].

The distribution of fibronectin and laminin, two glycoproteins involved in the migration of neural crest cells, was studied by an indirect immunohistofluorescence technique in 35 embryos and fetuses (from 6 weeks old to birth), 5 normal controls, and 6 patients with Hirschsprung's disease, in order to provide a new approach to the embryogenesis of human myenteric plexus and the pathogenesis of aganglionosis. Fibronectin was not seen near individual neuroblasts unlike myoblasts and mesenchymal cells which were surrounded by this macromolecule. There was a progressive and parallel cephalocaudal development of the plexus and the muscular layers from the esophagus to the intestine. However, in the rectum, at 7 weeks, neuroblasts were detected in close contact to fibronectin-labeled cells whereas they were not in the colon. These present results were in favor of two origins for neuroblasts: the vagal and the caudal neural crest cells. Faulty migration of caudal neural crest cells might be involved in the aganglionosis of Hirschsprung's disease in spite of the fact that local environment of fibronectin and laminin was identical to that of normal subjects.

Adult↗
PubMed1986

Detection of the plasmin system in human mammary pathology using immunofluorescence.

The presence and localization of the plasmin system components urokinase (UPA), tissue type plasminogen activator (TPA), plasminogen (PG), a neoantigen expressed by the plasmin-alpha 2-antiplasmin complex, and plasmin inhibitors alpha 2-antiplasmin (AP) and alpha 2-macroglobulin (MG) have been tested by immunofluorescence on sections of 11 benign and 40 malignant lesions of the breast in an attempt to apply a morphological approach to the problem of tumor invasion in vivo. In benign lesions, TPA was seen in secretions of mammary glands and MG was seen in edematous zones. In one involuting lactating adenoma, UPA, TPA, PG, PAP, and AP were associated with glandular cells. UPA was detected in 11 carcinomas, TPA in 22, PG in 31, PAP in 12, AP in 23, and MG in all 40. All these components were essentially present in invasive territories, with a cellular labeling for UPA and TPA and a fluorescent staining frequently at the periphery of tumoral foci for PG and PAP. AP was more closely associated with cancer cells than MG, which was present in the stroma. Intraductal proliferations were rarely positive and there was no correlation between the localization of PG and the distribution of a basement membrane glycoprotein laminin. These data argue strongly for the involvement of the plasmin system in the infiltrating process of the stroma. This system seems to play a limited role in the breakdown of basement membrane in breast carcinomas in vivo.

Adenofibroma↗