Question

part 2: how is mitotic index used in cancer studies?
mast cell tumors (mct) represent a range of mast cells, which are a type of white blood cell found in almost all tissues. mast cell tumors are the most common skin tumor in dogs. other organs are most commonly affected: lymph nodes, spleen, liver, and golden retrievers. mast tumors, histologic grade: grade i, ii, iii.
mast cell tumors are classified as one of three different histologic grades (grades i, ii, iii). grade i (low - grade) mct act as a benign neoplasm, and treatment can be cured with surgical removal. grade ii mct are more aggressive tumors that are locally invasive and have a high risk of spread (20 - 30%).
mitotic index (mi) is an indirect measure of cell proliferation that has been demonstrated to be a strong predictor of outcome for several human and canine cancers. the purpose of a study on dogs was to evaluate the utility of mi as a predictor of survival in dogs with cutaneous mast cell tumors (mcts).
a single pathologist evaluated the mi sections via light microscopy and generated an mi per 10 high - power (400x) fields (hpfs). the region of the tumor sample with the highest overall mitotic activity was chosen for evaluation. a single count of 10 hpfs was obtained for each tumor sample.

1. the data set below was sampled from a single specimen to illustrate how mitotic index can be determined.

the mitotic index is the ratio between the number of cells in mitosis and the total number of cells. calculate the mi for each data set.
\text{mitotic index}=\frac{#\text{ of cells in mitosis}}{\text{total }#\text{ of cells}}\times100

1. compare the mitotic index of the two types of tumors. what does this information tell you about the cells in the sample?

Explanation:

Step1: Analyze the Mitotic Index values

The mitotic index for Grade 1 tumor is \(3.31\%\) and for Grade 3 tumor is \(7.5\%\).

Step2: Relate Mitotic Index to cell proliferation

A higher mitotic index (\(MI\)) means a higher rate of cell division (proliferation).

Answer:

The mitotic index of Grade 3 tumor (\(7.5\%\)) is higher than that of Grade 1 tumor (\(3.31\%\)). This indicates that cells in Grade 3 tumor are dividing (proliferating) at a faster rate than cells in Grade 1 tumor.