Metallothionein as an epithelial proliferative compartment marker for DNA flow cytometry

Area of Science:

• Oncology
• Cell Biology
• Biochemistry

Background:

• Metallothionein (MT) is a low molecular weight protein involved in metal binding.
• MT antibody preferentially stains the proliferative edge of epithelial tumors in paraffin sections.
• Epithelial cell markers are crucial for accurate analysis in flow cytometry.

Purpose of the Study:

• To demonstrate the utility of the MT antibody as an epithelial cell marker in DNA flow cytometry.
• To evaluate MT staining for ploidy and cell cycle assessment in archival specimens.
• To investigate the potential of MT as an index of malignancy by identifying proliferating epithelial cells.

Main Methods:

• DNA flow cytometry was performed on archival specimens, including control breast and colon tissues, and breast and colon adenocarcinomas.
• Specimens were stained for both DNA and MT.
• Immunohistochemical staining was used to confirm MT's specificity for epithelial cells.

Main Results:

• MT antibody stained epithelial cells effectively in both control and cancerous tissues.
• The S-phase fraction (SPF), a measure of cell turnover, was significantly higher in MT-stained preparations compared to unstained ones, particularly in adenocarcinomas.
• MT staining identified a higher percentage of proliferating malignant epithelial cells, with an average of 47% of aneuploid cells showing MT staining.

Conclusions:

• MT antibody is a valuable tool for identifying epithelial cells in DNA flow cytometry of archival specimens.
• MT staining enhances the evaluation of cell ploidy and cell cycle, especially in cancer diagnostics.
• The preferential staining of proliferating cells by MT suggests its potential as a marker for malignancy.