What is the significance of Ki-67 in pathology?

Ki-67 is a crucial marker used in pathology to evaluate cellular proliferation. It is a nuclear protein that is expressed during active phases of the cell cycle, specifically from late G1 phase through S phase, G2 phase, and into mitosis. High levels of Ki-67 indicate a high degree of cell proliferation, making it an important tool in assessing tumor growth and aggressiveness.

The significance of measuring Ki-67 levels lies in its ability to provide insights into the behavior of a tumor. For instance, in cancer diagnosis, a high Ki-67 index often correlates with a more aggressive tumor, potentially influencing treatment decisions and prognosis. Therefore, it serves as a valuable prognostic tool beyond simply assessing whether a tumor is benign or malignant.

Understanding the role of Ki-67 is critical for pathologists as they evaluate different tumors and make decisions regarding management, as it reflects the biological activity of the cells within a tumor.