Demonstration of monoclonal origin of human parotid gland pleomorphic adenoma.
BACKGROUND
Parotid gland pleomorphic adenoma is histologically comprised of epithelial and mesenchymal elements. It remains to be established whether this neoplasm arises from epithelial and mesenchymal elements, or solely from the epithelial element.


METHODS
In an attempt to resolve this issue, we have conducted clonal analysis on five pleomorphic adenomas. The method for clonal analysis was based on the trinucleotide repeat polymorphism of the x-chromosome-linked androgen receptor gene and on random inactivation of this gene by methylation. The epithelial and mesenchymal elements were obtained separately from the paraffin sections of the pleomorphic adenomas using a microdissection technique and then subjected to clonal analysis.


RESULTS
Clonal analysis revealed that both epithelial and mesenchymal elements were monoclonal. In addition, the same allele of the androgen receptor gene was inactivated in both elements in every case.


CONCLUSIONS
It is unlikely that the epithelial and mesenchymal elements of different origin happen to inactivate the same allele of the androgen receptor gene in all five tumors. Rather, it is more reasonable to consider that these two elements have a common single cell origin.
Noguchi
S
S
Department of Surgery, Center for Adult Diseases, Osaka, Japan.
Aihara
T
T
Yoshino
K
K
Motomura
K
K
Inaji
H
H
Imaoka
S
S
Koyama
H
H
D008949:Adenoma, Pleomorphic / Q000235:genetics / Q000473:pathology*; D001483:Base Sequence; D002999:Clone Cells; D005260:Female; D006801:Humans; D008969:Molecular Sequence Data; D010307:Parotid Neoplasms / Q000235:genetics / Q000473:pathology*; D016133:Polymerase Chain Reaction; D011944:Receptors, Androgen / Q000235:genetics
D011944:Receptors, Androgen