Relationship between quantity of silver stained nucleolar organizer regions associated proteins (Ag-NORs) and population doubling time in ten breast cancer cell lines.

Using a one-step silver staining technique ten human breast cancer cell lines were investigated, determining by means of automated image analysis the mean area of Ag-NORs per nucleus, the total number of Ag-NORs, and the so-called "scattered" and "clustered" Ag-NORs. These parameters were statistically correlated with the population doubling time (PDT) of the various carcinoma cell lines of this series. Our results show that the mean area of Ag-NORs per nucleus (p less than 0.001) is highly significantly correlated to the PDT, whereas all other parameters were less or not significant. It is concluded that the assessment of the area of Ag-NORs by automated image analysis is a simple and reliable method for the determination of cell duplication rates.