Objective: To determine if the presence of cells having a DNA content > 5c and occurring at very low frequency is related to breast cancer outcome.
Study design: Feulgen-stained imprints of fresh tumors used for routine standard DNA image cytometry were reanalyzed, with the aim of detecting hyperploid (> 5c) cells or minor stemlines. Specially adapted software was used.
Results: The new DNA analysis showed discordance of 47.3% with standard DNA cytometry. Minor stemline or rarely occurring 5c exceeding cells were found. These were not detected by the first DNA analysis. The presence of both DNA hyperploid cells occurring as rare events and a DNA hyperploid stemline was related to outcome.
Conclusion: The detection of DNA hyperploid cells, even in very small numbers, appears essential to outcome, particularly in diploid or single DNA aneuploid breast cancers.