Practical breast carcinoma cell kinetics: review and update

Area of Science:

• Oncology
• Cell Biology
• Biophysics

Background:

• The S-phase fraction (SPF) and thymidine labeling index (TLI) are key indicators of cancer cell proliferation.
• These measures reflect the proportion of cells actively synthesizing DNA, offering insights into tumor growth dynamics.

Purpose of the Study:

• To investigate the relationship between proliferation markers (SPF and TLI) and clinicopathological features in breast carcinomas.
• To explore the prognostic significance of SPF and TLI, particularly in relation to aneuploidy and treatment outcomes.

Main Methods:

• Flow cytometry was used to measure DNA content and determine the S-phase fraction (SPF).
• Autoradiography was employed to measure the thymidine labeling index (TLI).
• Statistical analysis correlated TLI and SPF with tumor characteristics like aneuploidy, estrogen receptor (ER) status, and patient outcomes.

Main Results:

• TLI and SPF are lognormally distributed, with median TLI around 5% and mean SPF slightly higher.
• Aneuploid breast carcinomas, found in 50-80% of cases, exhibit higher TLI than diploid tumors, indicating more rapid proliferation.
• High TLI and SPF correlate inversely with estrogen and progesterone receptor (PgR) content, and predict a higher risk of early relapse and brain metastases.

Conclusions:

• Proliferation markers TLI and SPF are valuable indicators of breast cancer aggressiveness.
• Aneuploidy is associated with increased proliferation and may share prognostic significance with TLI.
• These findings suggest TLI and SPF can aid in risk stratification and predicting treatment response in breast cancer.