On a biopsy report
Ki-67
Also written as Ki67, Ki-67 index, Ki-67 score, Ki-67 proliferation index, MIB-1
What it means
Ki-67 is a protein found only in dividing cells. The Ki-67 score measures how fast cancer cells in a tumour are dividing. A high score means many cells are dividing quickly. A score over 30% is typically considered high.
Why it matters
It can help predict how well some cancers, such as breast cancer, respond to treatments like chemotherapy. Your oncologist reads it with other results.
Ask your oncologist
"What is my Ki-67 percentage, and how does it factor into my treatment?"
From NCI Dictionary of Cancer Terms: Ki-67 score. Not medical advice: your oncologist decides.