Cell Cycle & DNA Content Analysis Flashcards

Which dedicated software tool uses polynomial and Gaussian modeling algorithms specifically for automated cell cycle and DNA ploidy analysis?

Answer: ModFit LT

ModFit LT employs polynomial S-phase fitting combined with Gaussian G1 and G2/M peak modeling to deconvolute overlapping cell cycle compartments and calculate ploidy parameters.

What maximum CV for the G0/G1 peak is generally considered acceptable for clinical DNA ploidy analysis by flow cytometry?

Answer: Less than 5%

A CV below 5% for the G0/G1 peak is the widely accepted threshold for clinical DNA ploidy analysis, ensuring the G1 and G2/M peaks are sufficiently resolved to detect aneuploid populations.

Which antibody marker best helps distinguish tetraploid G1 cells (4N) from true G2/M cells (also 4N) in DNA content analysis?

Answer: MPM-2 anti-phosphoprotein antibody

MPM-2 recognizes phosphorylated epitopes present specifically on mitotic proteins during G2 and M phase, allowing discrimination of true G2/M cells from tetraploid G1 cells that share the same 4N DNA content.

In clinical oncology, a high S-phase fraction (SPF) detected by DNA content analysis in breast cancer is associated with:

Answer: More aggressive tumor behavior and worse prognosis

A high SPF indicates rapid cell proliferation, which correlates with more aggressive tumor biology, higher risk of recurrence, and worse clinical outcomes in breast cancer.

Which chemical agent is used to synchronize cells at the G1/S boundary by inhibiting ribonucleotide reductase?

Answer: Hydroxyurea

Hydroxyurea inhibits ribonucleotide reductase, depleting the deoxyribonucleotide pool and blocking DNA replication at the G1/S boundary without inducing DNA strand breaks.

When performing DNA ploidy analysis on a fresh tumor biopsy, what is the purpose of including normal stromal cells within the same specimen as an internal reference?

Answer: To establish the diploid G1 peak position for accurate DNA index calculation

Normal stromal or infiltrating lymphocytes within the tumor sample serve as an internal diploid control whose known 2N DNA content anchors the G1 reference peak for accurate DNA index calculation.

A tumor sample with a measured DNA index (DI) of 1.5 is best classified as:

Answer: Hyperdiploid aneuploid tumor cells with increased DNA content

A DI of 1.5 indicates the tumor G0/G1 peak is positioned 50% higher than the diploid reference, classifying the tumor as hyperdiploid aneuploid with an abnormally elevated DNA content.