Mitotic Index

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•  Determination of a mitotic index from a micrograph

The mitotic index is a measure of the proliferation status of a cell population (i.e. the proportion of dividing cells) 

The mitotic index may be elevated during processes that promote division, such as normal growth or cellular repair

  • It also functions as an important prognostic tool for predicting the response of cancer cells to chemotherapy

Identifying Mitotic Cells

Cells undergoing mitosis will lack a clearly defined nucleus and possess visibly condensed chromosomes

  • Prophase – Chromosomes condensed but still confined to a nuclear region
  • Metaphase – Chromosomes aligned along the equator of the cell
  • Anaphase – Two distinct clusters of chromosomes apparent at poles of the cell
  • Telophase – Two nuclear regions present within a single cell (difficult to see as cytokinesis occurs concurrently)

stages of mitosis

Calculating Mitotic Index

The mitotic index is the ratio between the number of cells in mitosis and the total number of cells

It can be determined by analysing micrographs and counting the relative number of mitotic cells versus non-dividing cells

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