Histological study of chordoma origin from fetal notochordal cell rests

摘要

STUDY DESIGN.: The histological comparative study was performed on chordoma and notochordal cell rests (NCRs). OBJECTIVE.: To understand the histological similarity and homology of chordoma and NCRs, further supplying direct evidence of chordoma origin from NCRs. SUMMARY OF BACKGROUND DATA.: Although many studies supported the hypothesis that chordoma arise from NCRs, there has been little direct evidence reported to date. Of the base of our previous study, we conducted a comparative histological study among NCRs coexisting in chordoma, fetal NCRs, and chordoma tumor components. METHODS.: Thirty fetal nucleus pulposus and 46 chordoma specimens were harvested, and classic chordoma tumor markers and brachyury expression levels were investigated through immunohistochemical method. RESULTS.: The fetal NCRs existed in the form of clusters in the center of nucleus pulposus <36 gestational weeks; NCRs coexisting in chordoma specimens consisted of packed cells without extracellular myxoid matrix. Both the above-mentioned NCRs as well as chordoma tumor components showed high sensitivity for classic chordoma tumor makers (epithelial membrane antigen, AE1/AE3, CAM5.2, vimentin, S-100); both kinds of NCRs showed completely negative expression for brachyury, whereas chordoma tumor components demonstrated 100% positivity. CONCLUSION.: Our study results supported histological similarity and homology of NCRs coexisting in chordoma and in fetal nucleus pulposus. Brachyury activation probably takes an important role in chordoma tumoregenesis.