DNA ANALYSIS OF CHOLESTEATOMAS
Background: Cholesteatoma is a destructive wound of the middle ear and/or mastoid, a process that produces complications by erosion of the temporal bone. The clinical hallmarks of cholesteatomas, namely: invasion, migration, uncoordinated proliferation, altered differentiation, aggressiveness and recidivism, are traits typically associated with the neoplastic cell.
However, there is little evidence to support or refute the speculation that cholesteatomas are a low-grade squamous cell neoplasm. The existence of defects in the genetic complement of the major cellular constituents comprising a cholesteatoma: fibroblasts and keratinocytes would support the speculation that cholesteatomas are a neoplam. Cancers commonly manifest quantitative and qualitative alterations in the normal euploid complement of genetic information. This results in a cell that has an abnormal or aneuploid amount of DNA.
Methods: DNA content (ploidy) within cholesteatoma tissues was measured by flow cytometry and image analysis.
Results: The DNA content of 11 human cholesteatomas and nine postauricular skin specimens was analyzed using flow cytometry, while the DNA content of 10 cholesteatoma specimens was analyzed using image analysis. Interpretable data was obtained from 10 cholesteatoma specimens and six postauricular skin specimens. One cholesteatoma specimen demonstrated an abnormal aneuploid DNA content, whereas the remaining nine cholesteatomas and the six postauricular skin specimens demonstrated a normal euploid DNA content.
Conclusions: We conclude that cholesteatomas are not low-grade neoplasms. There is a lack of overt genetic instability, as evidenced by the presence of a normal euploid DNA content.
Key Words: cholesteatoma, squamous cell neoplasis, DNA aneuploidy.