Expression of mitoses per thousand cells and cell density in breast carcinomas: a proposal

Morphometric applications in anatomic pathology

The components of the cell and tissue changes in many diseases are variable and can therefore be quantified. Characterization of these quantitative changes provides data that is useful not only for making a definitive, cell- and tissue-based diagnosis of disease, but also for predicting the course of disease. The spectrum of changes found in malignant tumors, ie, cell grade, architecture, cellularity, extent of invasion, nature and extent of inflammatory reaction, exemplify this range of quantifiable features. The diagnosis and prognosis of nonneoplastic diseases, ie, myopathy and metabolic bone disease, can also be determined by quantitating tissue changes. Morphometry is the quantification of changes in the "objects" of tissues, ie, cells and organelles, and their organization, using quantitative evaluation tools. The principles of morphometry have been known for a century. With the increasing availability of affordable, powerful computer systems and increasingly flexible and user-friendly software has come easier ability to measure these changes. This article discusses the principles of morphometry with illustrations of types of analysis (ie, area fraction, object counting, shape and size analyses, and mutliparametric analyses) using examples of these applications with discussions of error sources and limitations of morphometry.

Can you count on the mitotic index?

The mitotic index (MI) is the most commonly use quantitative measure in anatomic pathology but has been widely criticized for supposed "irreproducibility." In this article, the authors show that mitotic figure (MF) counts may be described by a Poisson distribution, give confidence intervals for the MI, and show that the supposed irreproducibility is largely a consequence of the counting techniques. They also show how to obtain the MI to a predetermined level of precision and present an analysis of why mitotic figure counting works, when properly used, despite the inherently low precision of the estimates that are usually obtained.

Prognostic significance of nuclear DNA content and proliferative activity in renal cell carcinomas. A clinicopathologic study of 58 patients using mitotic count, MIB-1 staining, and DNA cytophotometry

BACKGROUND

For a variety of human malignancies, static DNA cytophotometry and immunostaining for the Ki-67 antigen using the antibody MIB-1 have provided significant prognostic information.

METHODS

Surgical specimens of 58 renal cell carcinomas (RCCs) were investigated by conventional histology, DNA cytophotometry, and MIB-1 immunostaining.

RESULTS

The MIB-1 indices and DNA data were found not only to be significantly correlated with various other morphologic parameters, but also to the clinical behavior of RCC. In the course of this study (median observation period: 31 months), 27% of patients died from RCC. None of these patients belonged to the group of 37 patients with RCCs exhibiting diploid or euploid DNA histograms. Lethal outcome occurred in only 16 of the 21 patients (76%) with noneuploid or aneuploid histogram tumors (P < 0.0001). According to their MIB-1 indices and upon choosing different cutoff levels, the 58 RCCs were categorized into 2 groups with either low or high proliferative activity. Using the median and the mean MIB-1 index as cutoffs, none of the patients with tumors showing low proliferative activity had died, whereas 16 of 29 patients (55%) or, respectively, 16 of 25 patients (64%) with tumors exhibiting high proliferative activity, had died from RCC (P < 0.0001).

CONCLUSIONS

In addition to tumor grade and stage, both a high MIB-1 index and a noneuploid or aneuploid DNA histogram of a given RCC have the potential to identify tumor patients with an impaired prognosis.

Proliferation Markers and Their Uses in the Study of Endocrine Tumors

A growing body of literature supports the view that the proliferative activity (PA) of tumor cells is an important prognostic indicator for a variety of different tumors. We examined the role of PA in diagnosis and prediction or malignancy of endocrine tumors (ETs) of pituitary gland, pancreas, thyroid, parathyroid glands, adrenal glands, paraganglia, gastroenteric tract, and lung. The data in the literature indicate that the assessment of PA is not a diagnostic indicator of malignancy especially at the individual case level, whereas it can be useful for identifying subsets of malignant tumors with different aggressiveness potential, as well as for choosing therapeutic options in metatstatic lesions. We hope that, in the near future, multiparametric approaches including PA markers, cell growth and differentiation factors, and oncogenes will yield valuable information for diagnosis and prognosis of ETs also in individual cases.

Histological grading of breast carcinomas: a study of interobserver agreement

Interobserver variation in the histological grading of breast carcinoma was investigated using the hypothesis that optimal fixation, more precise grading guidelines, some experience, the use of training and test sets, and a comparison of results with an expert group might allow higher levels of agreement. For the training sets sections from 50 consecutive cases of breast carcinoma received at the Sir Charles Gairdner Hospital (SCGH) and fixed in both B5 and buffered formal saline (BFS) were graded by consensus of three pathologists at the SCGH and independently by consensus of two pathologists at the Nottingham City Hospital (NCH) using a modified Scarff-Bloom-Richardson histological grading system with guidelines as suggested by NCH pathologists. The section quality and degree of preservation of nuclear morphology were judged by NCH pathologists to be superior for B5-fixed material. Complete agreement in grade between SCGH and NCH results was achieved for 83.3% of B5-fixed cases and 73.5% of BFS-fixed cases (P = .05) with relative disagreement rates (RDRs) of 0.15 and 0.29 and kappa statistic values of 0.73 and 0.58, respectively. Approximately 80% complete agreement was achieved for tubule formation, nuclear score, and mitotic count, with RDRs ranging from 0.19 to 0.27 and kappa values from 0.46 to 0.69. There was a consistent bias in the SCGH results toward a higher tubule score in both B5- and BFS-fixed material because of a difference in interpretation of cribriform or complex gland patterns and a consistent bias in SCGH results toward a lower nuclear size/pleomorphism score for B5 and BFS material. For the test set sections from 50 further consecutive cases of breast cancer fixed in B5 were examined using similar criteria but taking into account the sources of error shown by the training set. Approximately 80% complete agreement was again achieved for grade components and grade (RDRs, 0.18 and 0.72). Systematic bias was reduced in the test set, but no other improvement was observed. Of the tumors designated as grade I by NCH, 87.5% were called grade I tumors by SCGH in the B5 training set, 84.6% in the B5 test set, and 66.6% in the BFS training set. The levels of agreement shown in both the training and test sets were satisfactory and represented a significant improvement over our previous study, suggesting that experience and precise grading guidelines are of value. The similar levels of agreement in training and test sets suggest that reasonable results can be achieved without direct training by expert groups.(ABSTRACT TRUNCATED AT 400 WORDS)

neu overexpression correlates with extent of disease in large cell ductal carcinoma in situ of the breast

In a retrospective study of ductal carcinoma in situ (DCIS) of the breast, the expression of the neu oncogene was determined immunohistochemically in 76 women treated by local excision or mastectomy. The histopathological features, including the extent of the lesion, histological subtype, cell type, and number of mitoses, were related to neu overexpression. Immunopositivity was found only in DCIS of large cell type, where it correlated with extent of disease but not with mitotic rate. Our findings, together with previous experimental evidence, suggest that this relationship is a consequence of the effect of the neu protein on cell motility.

Quantitative histopathology in ductal carcinoma of the breast. Prognostic value of mean nuclear size and mitotic counts

BACKGROUND

The prognostic value of quantitative histopathology was investigated in a retrospective study of 71 patients with ductal carcinoma of the breast. All patients were treated according to a standardized protocol. The median follow-up was 6 years.

METHODS

Measurements were performed in microscopic fields that were sampled systematically from the whole tumor area of a routine histologic section. The unbiased stereologic method of point-sampled intercepts was used to estimate the mean nuclear volume, [vv(nuc)]. Using a test system with points and counting frames, estimates were obtained of the mean nuclear profile area, [aH(nuc)], the nuclear volume fraction, [Vv(nuc/tis)], the nuclear profile density (ND), the mitotic profile frequency (MF), and the mitotic profile density (MD). Traditional clinicopathologic parameters and biochemical estrogen receptor status were recorded.

RESULTS

Single-factor survival analyses were significant regarding regional lymph node status, tumor dimension, clinical stage, age, aH(nuc), and vv(nuc) (P < or = 0.03). A tendency for prognostic value of MF was found (P = 0.10), whereas Vv(nuc/tis), ND, MD, histologic grade, and estrogen receptor status were insignificant. In a multivariate Cox analysis of patients with positive lymph nodes including the variables of tumor dimension, age, ND, vv(nuc), and MF, only vv(nuc) (P = 0.01) or MF (P = 0.004) were parameters of independent prognostic value.

CONCLUSION

The present feasibility study suggests that stereologic estimates of the mean nuclear volume and morphometric estimates of the mitotic profile frequency are of independent prognostic value for patients with ductal breast cancer with positive axillary lymph nodes. The prognostic information resulting from the two variables are correlated closely and cannot be separated in this study. Consequently, larger studies are needed. In addition, the independent value of quantitative histopathology in patients with lymph node negative breast cancer should be assessed.

Tumor vascularization, mitotic index, histopathologic grade, and DNA ploidy in the assessment of 114 head and neck squamous cell carcinomas

BACKGROUND

Quantification of tumor vascularization recently has been shown to a parameter of potential clinical significance. Several basic and clinical studies have demonstrated that tumor growth correlates significantly with angiogenesis.

METHODS

To determine the utility of quantification of tumor vascularization and mitotic index for the pathobiologic assessment of head and neck squamous cell carcinoma, a prospective study of 114 consecutively recruited primary neoplasms was performed. Tumors were also studied for differentiation, keratinization, nuclear atypia, growth pattern, inflammation, desmoplasia, vascular tumor emboli, and DNA content.

RESULTS

In this cohort, tumor vascularization was correlated with mitotic index (P < 0.001), nuclear grade (P = 0.03), presence of tumor emboli in the peripheral microvessels (P = 0.05), and lymph nodal status (P = 0.03). A strong relationship between poor differentiation and high N classification (P < 0.001), differentiation and keratinization (P < 0.001) and tumor cell emboli and clinically involved lymph nodes (P = 0.01) was also observed. Emboli were more rare in laryngeal and oropharynx/oral cavity tumors than in hypopharynx/epilarynx (P = 0.02).

CONCLUSIONS

This study indicates that tumor vascularization, differentiation, and tumor emboli in peripheral microvessel network are important histologic parameters in the assessment of squamous cell carcinoma of the head and neck.

Cocaine-induced liver injury in mice elicits specific changes in DNA ploidy and induces programmed death of hepatocytes

Liver injury was induced by a single dose (60 mg/kg) of cocaine in male albino Swiss mice untreated or pretreated with phenobarbital (in drinking water 1 gm/L), for 5 days before cocaine administration. One parameter of liver injury, serum isocitrate dehydrogenase activity, showed sharp increases at 24 hr of cocaine treatment; we also noted decrease hepatic levels of ATP, GSH, cytochrome P-450 and NADPH/NADP+ ratio and increases in malondialdehyde concentration. Histopathological study of liver slices showed perivenous and periportal necrosis induced by cocaine in untreated mice and mice pretreated with phenobarbital, respectively. A regenerative postnecrotic response, which peaked at 48 hr, was demonstrated by the appearance of mitotic cells. Mitotic index analysis showed that proliferative cells appear to be unevenly distributed in the hepatic acinus and were mainly located in the vicinity of the damaged acinar region. Genomic DNA ploidy and the distribution of DNA in the phases of the cell cycle were studied in nuclei of isolated hepatocytes. At 12 hr of cocaine administration, both in untreated and phenobarbital-pretreated mice, the following changes were observed: a sharp decrease in tetraploid (4N) cells (40% to 17% and 25% to 6%, respectively) and octoploid (8N) cells (5% to 2% and 2% to 1%, respectively), together with the appearance of a hypodiploid population (13% and 31%, respectively). Hypodiploid population was characterized as apoptotic cells by detection of DNA fragmentation in agarose gel. These results suggest that a significant percentage of cell death induced by cocaine occurs by means of the apoptosis death program. Comparison of the initial values of DNA ploidy with those obtained at 7 days of cocaine administration showed remarkable increases in polyploid populations (4N and 8N) and a decrease in diploid cells (2N), indicating that the process of differentiation occurs when liver restores its functionality.

Use of the mitotic counts for the prognosis and grading of breast cancer. Method evaluation study

Reproducibility of the volume fraction-corrected mitotic index (M/VV index) was studied in 144 unselected breast cancer specimens. The influence on decision making of variation in determining the index was also analysed. In the complete series of specimens the correlation between two observers, one subjectively estimating the epithelial fraction of tumor epithelium and the other using point-counting (10 x 10 ocular grid), was good (Pearson's r = 0.82, p < 0.001, 95% CI 0.70-0.92). A subset of 30 specimens was used to evaluate the grading efficiency (GE) of the M/VV index method. The mean grading efficiency as estimated from this subset varied between 90% and 93%. The average minimum GE value was 82.8% (SD = 3.4%). The findings suggest that when the M/VV index method is used, the grading is correct on average in 90% or more of the cases, but dependent on the cutoff point. The over-all grading efficiency of the M/VV index method was comparable to that obtained from published S-phase fraction data on breast cancer specimens from three independed laboratories. We conclude that the M/VV index in breast cancer analysis is a sufficiently reproducible method in mitosis counting, and that it can be used with subjective or point count estimation of the area fraction of neoplastic epithelium.

Proliferative activity assessed by anti-PCNA and Ki67 monoclonal antibodies in canine testicular tumours

The recent availability of monoclonal antibodies raised against cell cycle nuclear antigens makes possible, by means of immunohistochemical techniques, an easy and quick method of evaluating tumour kinetic activity, in addition to older methods such as measurement of the mitotic index. Some of these antibodies can be used on formalin-fixed paraffin wax-embedded samples, thus allowing the use of archival material. In the present study the proliferative activity of testicular tumours of the dog (seminomas and Sertoli and Leydig cell tumours) was investigated with two monoclonal antibodies to proliferating cell nuclear antigen (PCNA) clone PC10, and Ki67 clone MIB1. The former recognizes a formalin-resistant epitope of PCNA, and MIB1 the same antigen as Ki67 in formalin-fixed, paraffin wax-embedded sections after incubation in a microwave oven. Three parameters of proliferative activity were considered: PCNA and Ki67 indices (percentage of nuclear area positive to PCNA and to Ki67), and mitotic index (number of mitoses per 1000 cells). The PCNA index and Ki67 index revealed a good correlation in linear regression analysis (P < 0.001) as did the mitotic index (P < 0.01). None of the parameters considered revealed a significant difference in proliferative activity of the three types of tumour (P > 0.05-Spearman test), but in both seminomas and Sertoli cell tumours the progression from tubular to diffuse pattern paralleled an increase in growth fraction. It is interesting that some seminomas of the diffuse type, often considered on histological grounds to be the most malignant, showed the highest values of the above-mentioned parameters.

Increased mitotic activity as a negative prognostic indicator in pleomorphic xanthoastrocytoma. Case report

Pleomorphic xanthoastrocytoma is a recently characterized neoplasm with a favorable prognosis despite aggressive histological features. The authors report a case of pleomorphic xanthoastrocytoma that recurred 4 years after complete gross resection. The original tumor exhibited histological features characteristic of this neoplasm, but up to 4 mitoses/10 high-power fields were present focally. The recurrent tumor contained small foci of classical pleomorphic xanthoastrocytoma, but consisted predominantly of glioblastoma multiforme. Transitional zones contained nests of glial fibrillary acidic protein (GFAP)-immunopositive cells surrounded by delicate collagenous and reticulin-rich septa. Electron microscopy of the transitional zone showed continuous basal lamina investing cells containing bundles of intermediate filaments. These were GFAP-positive by immunogold electron microscopy, confirming the astrocytic nature of pleomorphic xanthoastrocytoma. This example illustrates the capacity of this tumor to evolve into glioblastoma. The indolent clinical behavior of most pleomorphic xanthoastrocytomas is evident from a literature review, which confirms the prolonged survival of many patients after onset of symptoms. Completeness of excision, subjectively assessed at surgery, did not influence the risk of recurrence or survival up to 10 years after initial resection. Postoperative radiotherapy did not improve survival, but may reduce the probability of recurrence; more studies are needed to corroborate this finding. The data compiled herein support the designation of pleomorphic xanthoastrocytoma as a distinct astrocytic neoplasm with a favorable prognosis. An increased mitotic rate has not previously been correlated with a worse outcome, and should not be used to exclude this diagnosis. However, anaplastic transformation of pleomorphic xanthoastrocytoma confers a much worse prognosis, and this case suggests that increased mitotic activity may be a negative prognostic indicator since it may herald subsequent anaplastic transformation.

Measurement and prediction of the short-term response of soft tissue sarcomas to chemotherapy

BACKGROUND

Preoperative chemotherapy has been advocated for the treatment of soft tissue sarcomas, yet there is little information about how these tumors respond pathologically to therapy or whether tumor response can be predicted from a pretreatment biopsy.

METHODS

Biopsy was done of 25 intermediate- or high-grade soft tissue sarcomas before they were treated with three cycles of doxorubicin and cisplatin and resected. The authors compared the pathologic features of the treated tumors with clinical and radiologic evidence of response to identify the pathologic features that best reflected chemotherapeutic effect. They analyzed the pretreatment biopsy specimens by light microscopic study and flow cytometry to identify parameters that predict short-term response to chemotherapy.

RESULTS

In the treated tumors, the clearest indicator of early chemotherapeutic effect was the percentage of the resected mass composed of viable neoplasm. Eleven of 25 resection specimens contained less than 15% viable neoplasm (patients with pathologic response); 9 of these had 5% or less. Flow cytometric estimates of the proliferative rate in the initial biopsy specimen predicted early chemotherapeutic effect; 7 of 10 tumors with S-phase fractions (SPF) greater than 6% responded pathologically, whereas only 3 of 12 tumors with lower SPF responded (P = 0.041). Initial tumor grade, cell type, percent tumor necrosis, mitotic rate, cellularity, and ploidy did not predict chemotherapy response.

CONCLUSION

These results indicate that soft tissue sarcomas often respond dramatically to chemotherapy, that the amount of residual viable sarcoma is an indicator of short-term effect, and that flow cytometric estimates of cell proliferation predict early response to chemotherapy.

Relationship between genomic DNA ploidy and parameters of liver damage during necrosis and regeneration induced by thioacetamide

Thioacetamide proved to be a potent necrogenic agent when a single dose of 6.6 mmol/kg was administered intraperitoneally to rats. Its necrogenic ability was assessed on the basis of morphological and biochemical changes. The injury of centrilobular hepatocytes showed a peak of cell death 24 hr after thioacetamide administration; it was followed immediately by the regenerative response. Parallel increases of serum aminotransferases, isocitrate dehydrogenase and gamma-glutamyl transferase activities were observed. Severe liver damage was also evident at 24 hr on the basis of glutathione depletion (29% of control), malondialdehyde production (169%), cytochrome P-450 level decrease (26%) and increased activity of glutathione S-transferase (160%). We checked the regenerative response by determining nuclear DNA content in isolated hepatocytes 0, 6, 12, 18, 24, 36, 48 and 72 hr after thioacetamide administration. Changes in DNA cell distribution between G0-G1, S and G2 + M phases of the cell cycle were observed. The sharp decrease in the percentage of the tetraploid cell population (G2 + M phases) and the abrupt increase of the S-phase cells at 36 and 48 hr suggest transition from adult to fetal in hepatocyte populations obtained 24 and 36 hr after thioacetamide treatment. At 72 hr of treatment, hepatocyte populations showed recovery to adult state. In the shift from the adult to fetal, registered at 24, 36 and 48 hr after thioacetamide administration, mitosis seemed to precede the synthesis of DNA.