DNA content analysis on a sample of breast tissue for suspected malignancy using flow cytometry and results DI = 2.5 and % cells in S phase = 29%. Based on these results you can conclude:

DNA content analysis on a sample of breast tissue for suspected malignancy using flow cytometry and results DI = 2.5 and % cells in S phase = 29%. Based on these results you can conclude:

• A. These results are likely indicative of a malignant breast tumor
• B. This is normal breast tissue
• C. These results are consistent with a mostly diploid population
• D. The results are not consistent with one another; no information is gained

Answer: (A)

Flow cytometry DNA content analysis looks at two things: how much DNA the cells contain (ploidy) and how many cells are actively duplicating their DNA (S-phase fraction). A DNA index of 2.5 means the dominant cell population has about 2.5 times the DNA content of normal diploid cells, which is a strong sign of aneuploidy. In many cancers, cells lose normal chromosome number or structure, producing such increased DNA content. The S-phase fraction of 29% indicates a high level of cell proliferation, which is also characteristic of malignant growth, where cells divide more rapidly than in normal tissue. Normal breast tissue would typically be mostly diploid (DNA index around 1.0) with a much lower S-phase fraction. Put together, aneuploid DNA content plus elevated proliferation aligns with a malignant breast tumor rather than normal tissue, so the result points toward malignancy.

Flow cytometry DNA content analysis looks at two things: how much DNA the cells contain (ploidy) and how many cells are actively duplicating their DNA (S-phase fraction). A DNA index of 2.5 means the dominant cell population has about 2.5 times the DNA content of normal diploid cells, which is a strong sign of aneuploidy. In many cancers, cells lose normal chromosome number or structure, producing such increased DNA content. The S-phase fraction of 29% indicates a high level of cell proliferation, which is also characteristic of malignant growth, where cells divide more rapidly than in normal tissue. Normal breast tissue would typically be mostly diploid (DNA index around 1.0) with a much lower S-phase fraction. Put together, aneuploid DNA content plus elevated proliferation aligns with a malignant breast tumor rather than normal tissue, so the result points toward malignancy.