Type of collagen in chordoma

Pepsin-soluble collagen was extracted from three histologically proven cases of chordoma and nucleus pulposus. The collagen types of these materials were investigated by differential salting-out, SDS-PAGE (sodium dodecyl sulphate-polyacrylamide gel electrophoresis) of native collagen and their CNBr (cyanogen bromide) cleaved peptides, and their amino acid compositions. Although the collagen of nucleus pulposus was type II, that of chordoma was largely type I. Collagen of notochord, the origin of nucleus pulposus, is known to be type II. Further investigation is necessary in view of the fact that collagen of chordoma, a tumor believed to be derived from notochord, is not type II.