Collagen

There are multiple types of collagen, divided into two major classes:

Fibril-forming

type I: the major type in dermis, tendons and bone

type II: found in cartilage

type III: found in connective tissue and forms the major component of reticulin

type V: found in the desmoplastic stromal reaction to tumours.
Non-fibril-forming

type IV: together with laminin, forms the major constituent of basement membrane.

type VII: found in the basement membrane underlying combined epithelia.

Immunohistochemical expression

Diagnostic utility

Type IV is useful in the distinction of in-situ from (micro)invasive carcinoma. In soft tissues, complete basement membranes form around endothelial, smooth muscle and Schwann cells: antibodies against laminin and collagen IV are useful for the identification of these lineages.

Type VII is associated with squamous differentiation of carcinomas.

References

1Diagnostic Immunohistochemistry edited by Professor D. J. Dabbs, page 70

This page last revised 21.12.2001.