Mitotic index

About: Mitotic index is a research topic. Over the lifetime, 3914 publications have been published within this topic receiving 101766 citations.

Evidence That Human Cardiac Myocytes Divide after Myocardial Infarction

Abstract: Background The scarring of the heart that results from myocardial infarction has been interpreted as evidence that the heart is composed of myocytes that are unable to divide. However, recent observations have provided evidence of proliferation of myocytes in the adult heart. Therefore, we studied the extent of mitosis among myocytes after myocardial infarction in humans. Methods Samples from the border of the infarct and from areas of the myocardium distant from the infarct were obtained from 13 patients who had died 4 to 12 days after infarction. Ten normal hearts were used as controls. Myocytes that had entered the cell cycle in preparation for cell division were measured by labeling of the nuclear antigen Ki-67, which is associated with cell division. The fraction of myocyte nuclei that were undergoing mitosis was determined, and the mitotic index (the ratio of the number of nuclei undergoing mitosis to the number not undergoing mitosis) was calculated. The presence of mitotic spindles, contractile ri...

Prognostic value of tumor infiltrating lymphocytes in the vertical growth phase of primary cutaneous melanoma.

Abstract: BACKGROUND Primary cutaneous melanoma is often infiltrated by lymphocytes that provide the opportunity to study what may be the local immunologic reaction to the tumor and to correlate the presence of these lymphocytes with overall survival. In an attempt to delineate the histologic diagnostic criteria, to classify different categories of lymphocytic infiltrates, previously described by Elder et al. as brisk, nonbrisk, and absent, and to verify their prognostic significance, we reviewed 285 consecutive cases of primary cutaneous melanomas (American Joint Committee on Cancer Stage I and II). METHODS In addition to clinical variables (age, sex, and location of tumor) and the presence of tumor infiltrating lymphocytes in the vertical growth phase, the histopathologic attributes reviewed included mitotic rate, thickness, and regression. The results were derived from independent histopathologic review by two pathologists (C.G.C., M.C.M., Jr.) on separate occasions. A multivariate analysis of survival was performed with the Cox's regression model. RESULTS The 5- and 10-year survival rates for melanoma with a vertical growth phase and a brisk infiltrate were 77% and 55%, respectively. For tumors with a nonbrisk infiltrate, the 5- and 10-year survival rates were 53% and 45%, respectively, and for tumors with absent tumor infiltrating lymphocytes, the 5- and 10-year survival rates were 37% and 27%, respectively. Mitotic index, thickness, and tumor infiltrating lymphocytes were statistically (univariate analysis) significant prognostic factors (P = 0.003, 0.000001, 0.0003, respectively), whereas the presence or absence of regression is not. In the univariate statistical analysis, the sex of patients and site of melanoma also were statistically significant (P = 0.00001 and 0.002 respectively), whereas age (P = 0.98) was not statistically significant. The multivariate analysis of thickness, mitotic rate, and tumor infiltrating lymphocytes showed that thickness and presence of tumor infiltrating lymphocytes were significant and independent histologic prognostic factors. With regard to the clinical factors, sex retained its independent prognostic significance. The histologic characteristics of melanoma with vertical growth phase (brisk, nonbrisk, and absent) are exemplified. CONCLUSIONS We demonstrated that when categories of tumor infiltrating lymphocytes are strictly defined, they indeed have very strong predictive value for primary cutaneous melanomas with a vertical growth phase. This work confirms the work of Clark et al. and fully illustrates the brisk, nonbrisk, and absent categories of infiltration. Finally, a multivariate analysis comparing thickness, mitotic rate and presence of tumor infiltrating lymphocytes showed that only thickness and presence of tumor infiltrating lymphocytes are significant and independent positive histologic prognostic factors. Cancer 1996;77:1303-10.

Problematic uterine smooth muscle neoplasms. A clinicopathologic study of 213 cases.

Abstract: A recent trend in the classification of uterine smooth muscle neoplasms (USMNs) into clinically benign and clinically malignant groups has been to move from exclusive reliance upon mitotic index (MI) to an approach that incorporates additional histopathologic characteristics. In furtherance of this goal, we assessed a variety of histopathologic features of 213 problematic smooth muscle neoplasms for which we had > or = 2 years of clinical follow-up data or for which there was an unfavorable outcome. One hundred and thirteen of these patients have had a minimum follow-up of 5 years, and 48 have been followed for > or = 10 years. Cases eliminated from the study group included USMNs with a significant myxoid or epithelioid component and cases of intravenous leiomyomatosis. USMNs, whether cellular or not, with no cytologic atypia and with a mitotic index (MI = number of mitotic figures [mf]/10 high-power fields [hpf]) of or = 10 mf/10 hpf, four of 10 failed.(ABSTRACT TRUNCATED AT 400 WORDS)

Prognosis of gastrointestinal smooth-muscle (stromal) tumors: dependence on anatomic site.

Abstract: Although the significance of various prognostic factors, such as tumor size and mitotic index (MI), has been well established for smooth-muscle tumors of the stomach, the significance of these factors in other sites is less well defined. We studied 1004 patients with gastrointestinal smooth-muscle tumors for whom vital status could be determined. The average MI and tumor size varied significantly among the five major sites examined: esophagus (53 cases), stomach (524 cases), small bowel 252 cases), colon/rectum (108 cases), and omentum/mesentery/peritoneum (67 cases). There was a significant difference in site-specific survival (p = 0.001), with 10-year survival varying between 50% and 70%. Multivariate analysis demonstrated tumor location (p = 0.0320), size (p = 0.0003), MI (p < 0.0001), and patient age (p < 0.0001) to each carry independent prognostic value. The significance of MI was highly site dependent. Separation of survival curves for the stomach, using a threshold for analysis of either 5 or 10 mitotic figures/50 high-power fields, was very good. In contrast, small-bowel tumors showed little separation between survival curves, regardless of whether a threshold of 1, 5, or 10 mitotic figures MF/50 high-power fields was used to distinguish groups. In no site were tumor size and MI alone sufficient to provide an accurate long-term prediction of prognosis. Although tumor location, size, MI, and age have independent value in predicting the prognosis of patients with gastrointestinal smooth-muscle tumors, better methods are still required to accurately predict clinical course.