MedicalTerminology DB

Meaning of S-phase fraction: A measure of the percentage of cells in a tumor that are in the phase of the cell cycle during which DNA is synthesized.

Definition of S-phase fraction

A measure of the percentage of cells in a tumor that are in the phase of the cell cycle during which DNA is synthesized. The S-phase fraction may be used with the proliferative index to give a more complete understanding of how fast a tumor is growing.

Written and maintained by James Murray Last updated July 21, 2026 Educational reference, not medical advice. Read the limitations.

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