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

Artificial Intelligence-Based Mitosis Scoring in Breast Cancer: Clinical Application

In recent years, artificial intelligence (AI) has demonstrated exceptional performance in mitosis identification and quantification. However, the implementation of AI in clinical practice needs to be evaluated against the existing methods. This study is aimed at assessing the optimal method of using AI-based mitotic figure scoring in breast cancer (BC). We utilized whole slide images from a large cohort of BC with extended follow-up comprising a discovery (n = 1715) and a validation (n = 859) set (Nottingham cohort). The Cancer Genome Atlas of breast invasive carcinoma (TCGA-BRCA) cohort (n = 757) was used as an external test set. Employing automated mitosis detection, the mitotic count was assessed using 3 different methods, the mitotic count per tumor area (MCT; calculated by dividing the number of mitotic figures by the total tumor area), the mitotic index (MI; defined as the average number of mitotic figures per 1000 malignant cells), and the mitotic activity index (MAI; defined as the number of mitotic figures in 3 mm2 area within the mitotic hotspot). These automated metrics were evaluated and compared based on their correlation with the well-established visual scoring method of the Nottingham grading system and Ki67 score, clinicopathologic parameters, and patient outcomes. AI-based mitotic scores derived from the 3 methods (MCT, MI, and MAI) were significantly correlated with the clinicopathologic characteristics and patient survival (P < .001). However, the mitotic counts and the derived cutoffs varied significantly between the 3 methods. Only MAI and MCT were positively correlated with the gold standard visual scoring method used in Nottingham grading system (r = 0.8 and r = 0.7, respectively) and Ki67 scores (r = 0.69 and r = 0.55, respectively), and MAI was the only independent predictor of survival (P < .05) in multivariate Cox regression analysis. For clinical applications, the optimum method of scoring mitosis using AI needs to be considered. MAI can provide reliable and reproducible results and can accurately quantify mitotic figures in BC.

Analysis of images for detection of oral epithelial dysplasia: A review

This paper provides a review of various image analysis approaches that have been previously used for recognition of dysplasia in images of the epithelium of the oral cavity. This domain has become especially admissible with the uncovering of the importance of image analysis which can probably be an aid to subjective diagnosis by histopathologists. Oral malignancy is a rampant form of cancer found among people of the Indian subcontinent due to various deleterious habits like consumption of tobacco, areca nut, betel leaf etc. Oral Submucous Fibrosis, a precancer, whose pathological category falls between normal epithelium and epithelial dysplasia, is caused because of these habits and can ultimately lead to oral cancer. Hence early detection of this condition is necessary. Image analysis methods for this purpose have an enormous potential which can also reduce the heavy workload of pathologists and to refine the criterion of interpretation. This paper starts with a critique of statistics of oral carcinoma in India and distribution of cancer in intra-oral sites and moves on to its causes and diagnostic approaches including causative agents, problems in curative approach and importance of image analysis in cancer detection. The various image analysis methods to appraise the cytological and architectural changes accompanied by Oral Epithelial Dysplasia in the images of the oral epithelial region have been described in relation to 2005 WHO Classification System and it was found that in future, analysis of images based on the mentioned methods has the potential in better interpretation and diagnosis of oral carcinoma.

Image analysis assisted study of mitotic figures in oral epithelial dysplasia and squamous cell carcinoma using differential stains

BACKGROUND

Mitosis is a process of cell division resulting in two genetically equivalent daughter cells. Excessive proliferation of cells due to mitosis is the hallmark in pre cancer and cancer.

AIMS

This study was conducted to count the number of mitotic figures in normal oral mucosa, oral epithelial dysplasia and squamous cell carcinoma in both Hematoxylin and Eosin (H&E) and Crystal Violet stained sections. Also the overall number of mitotic figures with both stains were compared along with the evaluation of staining efficacy of both the stains.

METHODS AND MATERIAL

The present study was conducted on 20 specimens each of the three categories. These were further divided into two groups for staining with H&E and with 1% Crystal Violet respectively. Images were captured and analyzed using image analysis software Dewinter Biowizard 4.1.

RESULTS

Comparison of mitotic figure count in three categories in sections stained with both stains showed statistically significant difference (p < 0.001). The mean number of mitotic figures seen in Crystal Violet reagent were significantly higher as seen in H&E stain (p < 0.001). The overall diagnostic efficacy of Crystal Violet was 87.6%. Crystal Violet scored over H&E stain and also helped to better appreciate metaphases in Squamous cell carcinoma and telophases in dysplasia.

CONCLUSION

Number of mitotic figures progressively increase with the advancement of the pathology. Use of 1% Crystal Violet provides better appreciation of mitotic figures and can be employed as a selective stain in routine histopathology.

p53 Protein and Proliferating Cell Nuclear Antigen (PCNA) Expression in Small Round Cell Tumors of Bone and Adjacent Soft Tissue

Sixty small cell tumors of bone and adjacent soft tissue were studied in an attempt to define the incidence of immunohistochemically detectable p53 protein and cor relate these findings with the results of proliferating cell nuclear antigen (PCNA) immunohistochemical staining and mitotic counts. All of the lesions had been for malin-fixed and paraffin-embedded; half were subjected to decalcification prior to processing. The study population included 12 Ewing's sarcomas of bone, 3 atypical Ewing's sarcomas of bone, 3 primitive neuroectodermal tumors of bone, 11 Askin tumors of the thoracopulmonary region, 11 small cell osteosarcomas of bone, 10 mesenchymal chondrosarcomas of bone, and 10 malignant lymphomas involving bone. The patients ranged in age at the time of presentation from 17 to 67 years. Overall, the incidence of p53 positivity was extremely low in these lesions, irre spective of tumor type. Positive nuclear staining with an antibody to p53 was found in none of the 12 Ewing's sarcomas, none of the 3 atypical Ewing's sarcomas, none of the 3 primitive neuroectodermal tumors of bone, 1 of the 11 Askin tumors of the thoracopulmonary region (1.5% of tumor cells positive), 1 of the 11 small cell osteosarcomas (2% of tumor cells positive), 1 of the 10 mesenchymal chondrosar comas of bone (7% of tumor cells positive), and 2 of the 10 malignant lymphomas involving bone (0.5% and 1% of tumor cells positive, respectively). The majority of tumors showed PCNA positivity within the tumor cells, although the incidence of PCNA positivity within the histologic types varied greatly; in general, the higher PCNA counts corresponded to higher mitotic counts within the individual lesions. The present study did not demonstrate any correlation between mutant p53 accu mulation detected by immunohistochemistry and tumor type, and so it is unlikely that p53 positivity will prove to be of great use in the differential diagnosis of these lesions. A correlation between p53 positivity and PCNA staining or mitotic activity was not apparent. Int J Surg Pathol 2(4):259-268, 1995

Analysis of the in vivo proliferative capacity of a whole cell cancer vaccine

A polyvalent therapeutic cancer cell vaccine containing three viable, irradiated, replication-incompetent melanoma cell lines (Canvaxin) was administered to over 2500 patients in various clinical studies. This study examines the fate of Canvaxin cells in 16 patients with Stage II, III or IV melanoma, with special attention on assessing the capacity of the vaccine cells to replicate. The survival time and the potential proliferative capacity of irradiated Canvaxin cells in humans was studied by histologic examination of biopsies of injection sites over a two-week period. The overall results show that the vaccine cell mitotic index in skin biopsies (0.12%) was approximately 6 times lower than the control value (0.71%). Similarly, there was an overall trend toward a decrease in mitotic figures during the two week observation periods. Also, there was a trend towards a decrease in the number of vaccine cells and mitotic figures with increasing cycles. The data indicate that Canvaxin cells do not proliferate after intra-dermal injection, and that cells typically associated with an immune response are present at the inoculation sites.

Comparison of tumor histology to dynamic contrast enhanced magnetic resonance imaging-based physiological estimates

PURPOSE

The purpose of this study was to compare histologically determined cellularity and extracellular space to dynamic contrast-enhanced magnetic resonance imaging (DCE MRI)-based maps of a two-compartment model's parameters describing tumor contrast agent extravasation, specifically tumor extravascular extracellular space (EES) volume fraction (ve), tumor plasma volume fraction (vp) and volume-normalized contrast agent transfer rate between tumor plasma and interstitium (KTRANS/VT).

MATERIALS AND METHODS

Obtained ve, vp and KTRANS/VT maps were estimated from gadolinium diethylenetriamine penta-acetic acid DCE T1-weighted gradient-echo images at resolutions of 469, 938 and 2500 microm. These parameter maps were compared at each resolution to histologically determined tumor type, and the high-resolution 469-microm maps were compared with automated cell counting using Otsu's method and a color-thresholding method for estimated intracellular (Vintracellular) and extracellular (Vextracellular) space fractions.

RESULTS

The top five KTRANS/VT values obtained from each tumor at 469 and 938 microm resolutions are significantly different from those obtained at 2500 microm (P<.0001) and from one another (P=.0014). Using these top five KTRANS/VT values and the corresponding tumor EES volume fractions ve, we can statistically differentiate invasive ductal carcinomas from noninvasive papillary carcinomas for the 469- and 938-microm resolutions (P=.0017 and P=.0047, respectively), but not for the 2500-microm resolution (P=.9008). The color-thresholding method demonstrated that ve measured by DCE MRI is statistically similar to histologically determined EES. The Vextracellular obtained from the color-thresholding method was statistically similar to the ve measured with DCE MRI for the top 10 KTRANS/VT values (P>.05). DCE MRI-based KTRANS/VT estimates are not statistically correlated with histologically determined cellularity.

CONCLUSION

DCE MRI estimates of tumor physiology are a limited representation of tumor histological features. Extracellular spaces measured by both DCE MRI and microscopic analysis are statistically similar. Tumor typing by DCE MRI is spatial resolution dependent, as lower resolutions average out contributions to voxel-based estimates of KTRANS/VT. Thus, an appropriate resolution window is essential for DCE MRI tumor diagnosis. Within this resolution window, the top KTRANS/VT values with corresponding ve are diagnostic for the tumor types analyzed in this study.

Interobserver agreement and reproducibility in classification of invasive breast carcinoma: an NCI breast cancer family registry study

The United States National Cancer Institute Breast/Ovarian Cancer Family Registry is the largest international Registry of this type; over 37 724 individuals have been enrolled to date. One activity of this Registry is the semicentralized pathologic review of tumors from all probands. Given the semicentralized nature of the review, this study was undertaken to determine the reproducibility, source(s) of classification discrepancies and stratagems to circumvent discrepancies for histologic subtyping and grading of invasive breast cancer among the reviewing pathologists. A total of 13 pathologists reviewed 35 invasive breast cancers and classified them by primary and secondary histologic type, Nottingham grade and score. Lymph-vascular space invasion, circumscribed margins, syncytial growth and lymphocytic infiltrate were also evaluated. A training session using a separate set of slides was conducted prior to the study. General agreement, in terms of category-specific kappa's and percent agreement, and accuracy of classification relative to a reference standard were determined. Classification of histologic subtype was most consistent (and accurate) for mucinous carcinoma (kappa=1.0), followed by tubular (kappa=0.8) and lobular subtypes (kappa=0.8). Classification of medullary subtype was moderate (kappa=0.4), but additional evaluation of degree of lymphocytic infiltrate, syncytial growth and circumscribed margins identified most cases. Category-specific kappa's were moderate to good for Nottingham grade (kappa=0.5-0.7), with the greatest agreement obtained in categorizing grade I (kappa=0.7), and grade III tumors (kappa=0.7). A flexible classification strategy that employs individual and combined criteria provides good interobserver agreement for invasive breast cancers with uniform, unambiguous histology and compensates for classification discrepancies in the more histologically ambiguous or heterogeneous cancers.

Apoptosis and nitric oxide in an experimental model of osteoarthritis in rabbit after hyaluronic acid treatment

OBJECTIVE

this study determine the effect of hyaluronic acid on chondrocyte apoptosis, as well as variations in nitric oxide levels in an experimental model of osteoarthritis elicited anterior cruciate ligament section (ACL) in a rabbit model with two differentiated developmental periods.

METHODS

apoptosis and the quantification of nitric oxide (NO) were studied in two groups of 16 animals each. All animals had both knees operated, but only the right knees were treated with hyaluronic acid (HA). In the first group hyaluronic treatment was performed five weeks after osteoarthritis induction (short term group, ST) and in the second group, 10 weeks after induction (long term group, LT). The animals in both series were sacrificed two weeks after the last dose of HA. Flow cytometry by means of Annexin labelling and the TUNEL method were used for the study of apoptosis, NO levels were measured in cultured cartilage and in the supernatant of the enzymatic digestion of the cartilage.

RESULTS

regarding apoptosis measurement, a significant reduction in apoptosis levels was observed in both series as compared to untreated knees. NO production was lower in knees treated with HA, with significant differences after cartilage digestion.

CONCLUSION

The administration of HA has been effective ameliorating the damage associated with the process of osteoarthritis induced by experimental surgery as evidenced by decreased apoptosis (TUNEL method), the results more promising in the earlier phases of the disease.

A proposal for a new and more practical grading scheme for pancreatic ductal adenocarcinoma

There is no uniformly applied grading system for pancreatic ductal adenocarcinoma (DA). The scheme advocated by the WHO is essentially that of Kloppel et al, and is based on the "highest grade" focus. Although it is precise with good prognostic value, it is unfortunately not widely applied, largely because of the lack of recognition and partly because of its complex nature (interpretation of multiple parameters). Furthermore, it is fundamentally different from the one used in Japan, which evaluates the overall pattern. To establish a more widely applicable, practical, and clinically relevant grading system, a scheme similar to Gleason's scoring system was developed and tested on 112 cases of resected pancreatic DA and was compared with the WHO system. In the grading system devised, patterns (P) of infiltration were classified as follows: P1, well-defined glands with easily discernible contours; P2, fused or poorly formed glands with ill-defined contours; P3, nonglandular patterns. A score was then obtained by the summation of the predominant and the secondary patterns. Scores < or =3 (at least some well-formed glands and no nonglandular pattern) was graded as G1, 4 as G2, and > or =5 (at least some nonglandular patterns and no well-formed glandular pattern) as G3. Seventy-three percent of the cases displayed mixed patterns, with disparate patterns (P1 with P3) in 13%, confirming the high degree of heterogeneity of DA. There was a significant correlation between grade and survival, better than the correlation between survival and either the major or minor patterns evaluated separately. The median survival for G1, G2, and G3 were 22, 14, and 8 months; 1-year survival 68%, 44%, and 33%; 2-year was 67%, 11%, and 0%; and 3-year was 23%, 4%, and 0%, respectively (P = 0.0019). In a multivariate analysis, correlating survival with grade, tumor size, and lymph node status, the grade was the strongest independent predictor of survival. Odds ratio of dying of disease were 3.56 (P < 0.0001) in G3 versus G1, 1.79 (P = 0.058) in G2 versus G1, and 1.98 (P = 0.03) in G3 versus G2. Compared with this, the same odds ratio were 1.17 (P = 0.01) in tumors >2 cm versus < or =2 cm and 1.78 (P = 0.01) in cases with positive versus negative lymph nodes. The WHO grading scheme was not found to have as good a correlation with survival in this study, with WHO grade 2 showing a better survival than 1. The reproducibility of both the proposed grading system and that of WHO were found to be moderately good (with kappa values of 0.43 and 0.44, respectively), when 32 slides of DA were graded by four independent observers. The grading scheme for pancreatobiliary adenocarcinoma proposed here is highly applicable because it is practical and readily adoptable. It reflects biologic characteristics of ductal carcinoma (prominent tubule formation and tumor heterogeneity). Most importantly, it is clinically relevant with good prognostic value. Lastly, it is also applicable for use in research, by utilizing "patterns," even in small specimens like microarrays or biopsies.

Overexpression of Nell-1, a craniosynostosis-associated gene, induces apoptosis in osteoblasts during craniofacial development

We studied the cellular function of Nell-1, a craniosynostosis-related gene, in craniofacial development. Nell-1 modulates calvarial osteoblast differentiation and apoptosis pathways. Nell-1 overexpression disrupts these pathways resulting in craniofacial anomalies such as premature suture closure.

INTRODUCTION

Craniosynostosis (CS), one of the most common congenital craniofacial deformities, is the premature closure of cranial sutures. Previously, we reported NELL-1 as a novel molecule overexpressed during premature cranial suture closure in patients with CS. Nell-1 overexpression induced calvarial overgrowth and resulted in premature suture closure in a rodent model. On a cellular level, Nell-1 is suggested to promote osteoblast differentiation.

MATERIALS AND METHODS

Different levels of Nell-1 were introduced into osteoblastic cells by viral infection and recombinant protein. Apoptosis and gene expression assays were performed. Mice overexpressing Nell-1 were examined for apoptosis.

RESULTS

In this report, we further showed that overexpression of Nell-1 induced apoptosis along with modulation of apoptosis-related genes. The induction of apoptosis by Nell-1 was observed only in osteoblastic cells and not in NIH3T3 or primary fibroblasts. The CS mouse model overexpressing Nell-1 showed increased levels of apoptosis in the calvaria.

CONCLUSION

We show that Nell-1 expression modulates calvarial osteoblast differentiation and apoptosis pathways. Nell-1 overexpression disrupts these pathways resulting in craniofacial anomalies such as premature suture closure.

Are cellular polarisation and mitotic frequency prognostic factors for local recurrence in patients with ductal carcinoma in situ of the breast?

There is still no generally accepted histopathological classification system for ductal carcinoma in situ (DCIS) of the breast. Nuclear grade, with or without other histopathological parameters (i.e. comedo-type necrosis and cellular polarisation), has been demonstrated to yield prognostic information. A detailed method for the evaluation of the mitotic frequency in DCIS, based on an approach by Contesso, was used in this study. We also investigated if cellular polarisation and mitotic frequency were important for the ipsilateral local recurrence-free interval (IL-RFI) in 121 DCIS patients who had been operated upon with breast-conserving treatment (BCT) without radiotherapy. Both cellular polarisation and the mitotic frequency were associated with histopathological and cellular biological factors (in previous evaluations), and were of borderline significance for IL-RFI in the univariate analyses. However, when nuclear grade was included in the multivariate analyses (with or without the growth pattern), neither cellular polarisation nor the mitotic frequency were of any independent prognostic value.

Pathological features of breast cancer response following neoadjuvant treatment with either letrozole or tamoxifen

Morphological characteristics, grading features, proliferation marker MIB1, apoptosis (by Tdt-mediated duTP-biotin nick-end labelling (TUNEL)), Bcl-2 expression, oestrogen receptor (ER) and progesterone receptor (PgR) status were compared in ER-positive breast cancers before and after 3 months of neoadjuvant therapy with either letrozole or tamoxifen. Daily treatment was with letrozole 2.5 mg (12 patients) or 10 mg (12 patients), or with tamoxifen 20 mg(24 patients). Letrozole treatment was associated with a pathological response in 17 of 24 (71%) patients. The predominant change in grading features was a decrease in mitosis, and the expression of MIB1 was reduced in all of the 22 evaluable cases. Whilst only marginal changes were observed in ER expression following letrozole therapy, PgR reactivity was reduced in 20 of 21 evaluable cases which were initially PgR-positive, becoming undetectable in 16 patients. Tamoxifen treatment was associated with pathological response in 15 of 24 (63%) tumours. In contrast to letrozole, the dominant change in grading feature was an increase in tubule formation, ER score was markedly reduced in most cases, and the most common effect on PgR was an increased expression. Following treatment with either tamoxifen or letrozole, variable effects were observed on the apoptotic index and expression of Bcl-2. These results indicate that both letrozole and tamoxifen have marked influences on the pathological features of breast cancer during neoadjuvant therapy. However, the effects of the two agents varied such that the phenotypes of letrozole- and tamoxifen-treated tumours differ markedly. Effects on clinical, pathological and biological endpoints were frequently disconcordant--future studies will therefore require the evaluation of multiple parameters in order to fully assess tumour response.

Apoptotic bodies as a morphological feature in serous ovarian carcinoma: correlation with nuclear grade, Ki-67 and mitotic indices

This study evaluated the relation of apoptosis with mitotic activity, Ki-67 indices, and nuclear and architectural grades in serous ovarian carcinoma. Apoptotic body (ABI) and mitotic indices (MI) were obtained by examining hematoxylin and eosin-stained sections from 35 serous ovarian carcinomas for apoptotic bodies and mitotic figures. ABI and MI were reported as the number of apoptotic bodies, and mitotic figures and immunostaining for Ki-67, respectively, as positive cells in 1000 cells. Nuclear grade was determined as grade 1 [n = 11], grade 2 [n = 13], and grade 3 [n = 11] according to recently defined criteria. There was a significant correlation between Ki-67 indices and ABI (p < 0.0001), Ki-67 and MI (p < 0.0001), as well as between MI and ABI (p < 0.0001). ABI increased with nuclear grade (p < 0.0001) and the type of the histological differentiation pattern (from glandular to papillary and solid architectural patterns) (p < 0.0001). Apoptosis, quantitated by ABI, is positively correlated with proliferation, thereby constituting a factor in the regulation of tumor growth of serous ovarian carcinomas. The positive correlation between ABI and increasing nuclear grade, mitotic activity, and architectural growth pattern may indicate that apoptotic bodies are another variable for grading serous ovarian carcinomas.

Effect of neoadjuvant treatment with anastrozole on tumour histology in postmenopausal women with large operable breast cancer

Anastrozole is an orally active, non-steroidal aromatase inhibitor which appears effective as neoadjuvant treatment of breast cancer. Histological changes have been evaluated in biopsies from large, oestrogen-receptor rich, operable breast tumours in postmenopausal women following 12 weeks of neoadjuvant anastrozole treatment (1 mg (n=12) or 10 mg (n=11)). Of the 23 patients, 18 had a clinical response following treatment. Compared with pre-treatment biopsies anastrozole-treated specimens displayed decreased cellularity and/or increased fibrosis in 15 tumours; changes in gland formation, nuclear pleomorphism, or mitoses, in 12 cases; and a reduction in Mib1 score in all tumours. Marked changes in apoptotic scores were seen following treatment but the direction of effect was inconsistent. In all 17 tumours which were positive for progesterone receptors before therapy, treatment was associated with reduced staining for progesterone receptors. There was no consistent effect of treatment on oestrogen-receptor expression. It is concluded that neoadjuvant anastrozole treatment in this patient group has marked effects on tumour histopathology but these do not always correlate with clinical response.

Kinetic profiles by topographic compartments in muscle-invasive transitional cell carcinomas of the bladder: role of TP53 and NF1 genes

We evaluated 71 muscle-invasive transitional cell carcinomas (TCCs) of the bladder by tumor compartments. Kinetic parameters included mitotic figure counting, Ki-67 index, proliferation rate (DNA slide cytometry), and apoptotic index (in situ end labeling [ISEL] of fragmented DNA using digoxigenin-labeled deoxyuridine triphosphate and Escherichia coli DNA polymerase [Klenow fragment]). At least 50 high-power fields per compartment were screened from the same tumor areas; results are expressed as percentage of positive neoplastic cells. Mean and SD were compared by tumor compartment. DNA was extracted from microdissected samples (superficial and deep) and used for microsatellite analysis of TP53 and NF1 by polymerase chain reaction-denaturing gradient gel electrophoresis. Significantly higher marker scores were revealed in the superficial compartment than in the deep compartment. An ISEL index of less than 1% was revealed in 63% (45/71) of superficial compartments and 86% (61/71) of deep compartments. Isolated NF1 alterations were observed mainly in superficial compartments, whereas isolated TP53 abnormalities were present in deep compartments. Lower proliferation and down-regulation of apoptosis define kinetically the deep compartment of muscle-invasive TCC of the bladder and correlate with the topographic heterogeneity, NF1-defective in superficial compartments and TP53-defective in deep compartments.

Cell proliferation and tumors of the central nervous system. Part 1: Evaluation of mitotic activity

Evaluation of cell proliferation has been long recognized in pathology as a mainstay of diagnosis and important in the prognostication of a variety of neoplasms. Routine light microscopic evaluation of mitotic activity has long served as a reasonable assessment of cell proliferation. Counting mitotic figures has the advantage of being inexpensive and relatively quick. The main objections leveled against utilization of mitosis counts in diagnostic decision making are related to the instability of mitotic figures due to prefixation and fixation issues and problems with interobserver reproducibility of counts. This paper reviews factors that affect the identification of mitotic figures and the determination of mitosis counts. The role mitosis evaluation plays in the evaluation of certain neoplasms of the central nervous system is discussed.

DNA topoisomerase II-alpha in pulmonary carcinoid tumors

Fifty-four pulmonary carcinoid tumors of surgically treated patients were diagnosed according to modified Arrigoni histological criteria (WHO 1999). Forty-seven typical (TC) and seven atypical carcinoids (AC) formed the basic groups. Four subgroups were selected from the TCs and consisted of cases with higher tumor size (T2) or those associated with nodal involvement (N1), tumor satellites, and tumorlets. Subgroup tumors were regarded as affections with possible increased proliferation potential. The proliferate activity was examined immunohistochemically by topoisomerase II-alpha (clone SWT3D1) on paraffin material and calculated by the number of positive nuclei per 10 HPF. The topoisomerase expression was found to be statistically different in both principal groups made up of typical and atypical carcinoids with a mean value of 49 and 135 positive nuclei per 10 high power field in TC and AC, respectively. The remaining subgroups of the TCs associated with examined characteristics (larger tumor diameter, metastases, satellites, tumorlets) were not found to be statistically different. The topoisomerase II-alpha is a marker giving valuable information about the diagnosis of pulmonary typical and atypical carcinoids.

Germline RET 634 mutation positive MEN 2A-related C-cell hyperplasias have genetic features consistent with intraepithelial neoplasia

C-cell hyperplasias are normally multifocal in multiple endocrine neoplasia type 2A. We compared clonality, microsatellite pattern of tumor suppressor genes, and cellular kinetics of C-cell hyperplasia foci in each thyroid lobe. We selected 11 females from multiple endocrine neoplasia type 2A kindred treated with thyroidectomy due to hypercalcitoninemia. C-cell hyperplasia foci were microdissected for DNA extraction to analyze the methylation pattern of androgen receptor alleles and microsatellite regions (TP53, RB1, WT1, and NF1). Consecutive sections were selected for MIB-1, pRB1, p53, Mdm-2, and p21WAF1 immunostaining, DNA content analysis, and in situ end labeling. Appropriate tissue controls were run. Only two patients had medullary thyroid carcinoma foci. Nine informative C-cell hyperplasia patients showed germline point mutation in RET, eight of them with the same androgen receptor allele preferentially methylated in both lobes. C-cell hyperplasia foci showed heterogeneous DNA deletions revealed by loss of heterozygosity of TP53 (12 of 20), RB1 (6 of 14), and WT1 (4 of 20) and hypodiploid G0/G1 cells (14 of 20), low cellular turnover (MIB-1 index 4.5%, in situ end labeling index 0.03%), and significantly high nuclear area to DNA index ratio. MEN 2A (germline point mutation in RET codon 634) C-cell hyperplasias are monoclonal and genetically heterogeneous and show down-regulated apoptosis, findings consistent with an intraepithelial neoplasia. Concordant X-chromosome inactivation and interstitial gene deletions suggest clone expansions of precursors occurring at a point in embryonic development before divergence of each thyroid lobe and may represent a paradigm for other germline mutations.

Mitotic counting in surgical pathology: sampling bias, heterogeneity and statistical uncertainty

Mitotic counting in surgical pathology: sampling bias, heterogeneity and statistical uncertainty Although several articles on the methodological aspects of mitotic counting have been published, the effects of macroscopic sampling and tumour heterogeneity have not been discussed in any detail. In this review the essential elements for a standardized mitotic counting protocol are described, including microscopic calibration, specific morphological criteria, macroscopic selection, counting procedure, effect of biological variation, threshold, and the setting of an area of uncertainty ('grey area'). We propose that the use of a standard area for mitotic quantification and of a grey area in mitotic counting protocols will facilitate the application of mitotic counting in diagnostic and prognostic pathology.

Differential expression of cytokine mRNA in skin specimens from patients with erythema migrans or acrodermatitis chronica atrophicans

Erythema migrans, the characteristic skin manifestation of acute Lyme borreliosis, is a self-limited lesion. In contrast, acrodermatitis chronica atrophicans, the typical cutaneous manifestation of late Lyme borreliosis, is a chronic skin condition. In an effort to understand pathogenic factors that lead to different outcomes in dermatoborrelioses, skin biopsy samples from 42 patients with erythema migrans and 27 patients with acrodermatitis chronica atrophicans were analyzed for mRNA expression of five pro-inflammatory cytokines (tumor necrosis factor alpha, interleukin-1 beta, interleukin-6, interferon-gamma, and interleukin-2) and two anti-inflammatory cytokines (interleukin-4 and interleukin-10) by in situ hybridization with cytokine-specific riboprobes. Among the 27 patients who had erythema migrans alone with no associated signs or symptoms, the major cytokines expressed in perivascular infiltrates of T cells and macrophages were the pro-inflammatory cytokine interferon-gamma and the anti-inflammatory cytokine interleukin-10. In the 15 erythema migrans patients who had associated signs and symptoms, including headache, elevated temperature, arthralgias, myalgias, or fatigue, a larger number of macrophages and greater expression of macrophage-derived pro-inflammatory cytokines, tumor necrosis factor alpha, interleukin-1 beta, and interleukin-6, were also found. In comparison, infiltrates of T cells and macrophages in the skin lesions of acrodermatitis chronica atrophicans patients had very little or no interferon-gamma expression. Instead, they usually expressed only the pro-inflammatory cytokine tumor necrosis factor alpha and the anti-inflammatory cytokine interleukin-4. Thus, the activation of pro-inflammatory cytokines in erythema migrans lesions, particularly interferon-gamma, seems to be important in the control of the spirochetal infection. In contrast, the restricted pattern of cytokine expression in acrodermatitis chronica atrophicans, including the lack of interferon-gamma, may be less effective in spirochetal killing, resulting in the chronicity of this skin lesion. J Invest Dermatol 115:1115-1123 2000

Clonal patterns in phaeochromocytomas and MEN-2A adrenal medullary hyperplasias: histological and kinetic correlates

The relationship among histological features, cell kinetics, and clonality has not been studied in adrenal medullary hyperplasias (AMHs) and phaeochromocytomas (PCCs). Thirty-four PCCs (23 sporadic and 11 MEN-2A (multiple endocrine neoplasia type 2A)-related tumours, the latter associated with AMH) from females were included in this study. Representative samples were histologically evaluated and microdissected to extract DNA and evaluate the methylation pattern of the androgen receptor alleles. At least two tissue samples (from the peripheral and internal zones in each tumour) were analysed with appropriate tissue controls run in every case. The same areas were selected for MIB-1 staining and in situ end labelling (ISEL). Malignant PCCs were defined by histologically confirmed distant metastases. All monoclonal AMH nodules from the same patient showed the same X-chromosome inactivated. Six sporadic PCCs revealed liver metastases (malignant PCC) and eight additional sporadic PCCs showed periadrenal infiltration (locally invasive PCC). All informative PCCs were monoclonal, except for five locally invasive PCCs and one benign PCC that revealed polyclonal patterns. Those cases also showed a fibroblastic stromal reaction with prominent blood vessels, focal smooth muscle differentiation, and significantly higher MIB-1 (126.8+/-29.9) and ISEL (50.9+/-12.8) indices. Concordant X-chromosome inactivation in nodules from a given patient suggests that MEN-2A AMH is a multifocal monoclonal condition. A subgroup of PCCs characterized by balanced methylation of androgen receptor alleles, high cellular turnover, and stromal proliferation also shows locally invasive features.

Evaluation of the interobserver agreement in the number of mitotic figures of breast carcinoma as simulation of quality monitoring in the Japan National Surgical Adjuvant Study of Breast Cancer (NSAS-BC) protocol

In the National Surgical Adjuvant Study for Breast Cancer (NSAS-BC), node-negative breast cancers were divided into higher- and lower-risk groups according to the histopathological nuclear grade given at individual collaborating hospitals, and the higher-risk group was entered into a randomized protocol of adjuvant therapy. Because the nuclear grade was the composite of nuclear atypia and mitotic counts, maintenance of interobserver agreement in mitotic counts was indispensable for the success of the protocol study. Fourteen pathologists participating in the protocol judged whether or not 20 photomicrographs suspected of showing mitotic cancer-cell figures truly showed mitoses. After standardizing the counting method, these pathologists counted the number of mitotic figures per 10 high-power fields of hematoxylin-eosin-stained main-tissue sections of 20 tumors. Areas where mitotic counts were considered to be the most frequent by each pathologist were compared for these tumors. For the judgment of whether the photomicrograph indicated mitosis, the level of interobserver agreement was moderate (kappa = 0.569). In the observations of 20 tumors, interobserver agreement level of mitotic counts was moderate (kappa = 0.506), that of nuclear atypia scoring was fair (kappa = 0.265), and that of nuclear grading was substantial (kappa = 0.633). The counted area was almost the same among the observers in 9 tumors, split into two areas in 6, and dispersed in 5. Concordance in judgment was achieved in 7 of the first 9 and in all of the third 5, but only in one of the second 6. The cause of discordance was mostly derived from tumor heterogeneity and the difference in the site where mitoses were counted. Interobserver agreement level was considered to be satisfactory, and it was expected that the case entry would be performed appropriately in the protocol study. The selection of the counting area was confirmed to be important for the acquisition of high-level agreement level in mitotic counts.

Molecular evolution and intratumor heterogeneity by topographic compartments in muscle-invasive transitional cell carcinoma of the urinary bladder

Superficial transitional cell carcinomas (TCC) of the urinary bladder have been shown to be monoclonal. However, no combined study of clonality and tumor suppressor genes (TSG) is available to date for muscle-invasive TCC. Forty-four muscle-invasive TCC of the urinary bladder selected from women were included in this study. Tumor cells located above and below the muscularis mucosa zone were systematically microdissected and used for DNA extraction. Hha-I digested and undigested samples were used to study the methylation pattern of androgen receptor alleles and undigested samples were used for microsatellite analysis of TSG (TP53, RB1, WT1, and NF1). Both loss of heterozygosity (LOH) and single nucleotide polymorphism (SNP) analyses were performed using optimized denaturing gradient gel electrophoresis. The expression of p53, pRB, and p21WAF1 was assessed by immunohistochemistry. Appropriate controls were run in every case. All except two TCC showed a monoclonal pattern with the same allele inactivated in both compartments. Microsatellite analysis of TSG revealed the same LOH/SNP pattern in both tumor compartments in 30 cases (involving more than 1 TSG locus in 8) and genetic heterogeneity in 14 cases. From the latter group, 9 cases expressed more genetic changes in the deep compartment (involving TP53 gene in all cases, WT1 gene in 2, and NF1 in 1), whereas in 4 cases the superficial compartment showed more genetic changes (three involving NF1 and one involving both RB and TP53). No statistical difference in the immunoexpression was detected, although it tended to be higher in the superficial compartment than in the deep compartment. These concordant data in polymorphic DNA regions indicate that bladder-muscle-invasive TCC are monoclonal proliferations with homogeneous tumor cell selection. Heterogeneous tumor cell selection by topography defined two different genetic compartments: superficial, NF1-defective, and deep, TP53-defective. No differences in the immunohistochemical expression were observed, precluding a more extensive clinical application.

Angiogenic Index: A New Method for Assessing Microvascularity in Breast Carcinoma with Possible Prognostic Implications

The quantitation of microvessels in breast cancer in sections immunolabeled for factor VIII, CD-34, or CD-31 currently is expressed as numbers of vessels/mm2. In an attempt to perform a more accurate method for counting microvessels, we determined the number of microvessels by 1,000 tumor cells (angiogenic index; AI). This new method minimizes the possible variations concerning the width of the microscopic fields, stroma/epithelium relations, and cellular tumor size. The present study compares the number of vessels determined by the traditional method (vessels/mm2) and AI in a series of 215 cases of ductal infiltrating carcinoma not otherwise specified. Also we studied the degree of correlation between both methods and with pathologic variables (tumor size, histologic grade, mitotic count, tumor necrosis, vascular invasion, skin infiltration, and axillary lymph node metastasis). Our results showed that the AI correlates more significantly than the classic microvessel density determination with other prognostic factors in breast cancer. In histologic grade III tumors, high AI correlates significantly with the presence of more than three axillary lymph nodes metastases. Therefore we recommend determining the degree of tumor angiogenesis by counting vessels per 1,000 tumor cells (AI) because of its reliable determination and significant correlation with other prognostic factors.

Clonality as expression of distinctive cell kinetics patterns in nodular hyperplasias and adenomas of the adrenal cortex

Although histopathologic criteria for adrenal cortical nodular hyperplasias (ACNHs) and adenomas (ACAs) have been developed, their kinetics and clonality are virtually unknown. We studied 20 ACNHs and 25 ACAs (based on World Health Organization criteria) from 45 females. Representative samples were histologically evaluated, and the methylation pattern of the androgen receptor alleles was analyzed on microdissected samples. Consecutive sections were selected for slide cytometry, flow cytometry, and in situ end labeling (ISEL). Apoptosis was studied by flow cytometry (nuclear area/DNA content plotter analysis) and by ISEL. Appropriate tissue controls were run in every case. Polyclonal gel patterns were revealed in 14/18 informative ACNHs and in 3/22 informative ACAs, whereas monoclonal gel patterns were observed in 4/18 ACNHs and 19/22 ACAs. Overlapping proliferation rates (PRs) were observed in both clonal groups, and apoptosis was detected only in G(0)/G(1) cells, especially in monoclonal ACNHs (3/4; 75%) and in polyclonal ACAs (2/3; 67%). Significantly higher PRs were observed in ACNHs with polyclonal patterns and G(0)/G(1) apoptosis and in ACAs regardless of clonality pattern and presence of G(0)/G(1) apoptosis. All except one ACNH (19/20; 95%) and 15/25 ACAs (60%) showed diploid DNA content, whereas the remaining cases were hyperdiploid. A direct correlation between PR and ISEL was observed in polyclonal lesions (PR = 29.32 ISEL - 1.93), whereas the correlation was inverse for monoclonal lesions (PR = -9.13 ISEL + 21.57). We concluded that only simultaneous down-regulated apoptosis and high proliferation result in selective kinetic advantage, dominant clone expansion, and unbalanced methylation patterns of androgen receptor alleles in ACNHs and ACAs.

Predictors of axillary lymph node metastases in patients with invasive breast carcinoma by a combination of classical and biological prognostic factors

The presence of axillary lymph node metastases (ALNMs) is the most important prognostic factor in breast carcinoma. If ALNMs were predictable without performing axillary lymph node dissection (ALND), this procedure would not be necessary in selected patients. Using a combination of some of the new biological markers with the classical ones, our objective was I) to identify the best set of predictors of ALNMs, and II) to define predictive models with either high or low probability of ALNMs. We studied 102 patients with invasive breast carcinoma. All patients underwent ALND, and at least 10 axillary lymph nodes per case were obtained. In the primary tumour we evaluated size, histological subtype and grade, lymphatic/vascular invasion and margin. Hormone receptor status, MIB1 index, microvessel density, c-erbB-2 and cathepsin D expression were assessed by immunohistochemistry, and DNA ploidy and S-phase by flow cytometry. Risk factors for ALNMs were estimated by nonlinear logistic regression analysis. The best predictors of ALNMs were: tumour size > 2 cm [OR 6.45, 95% confidence interval (CI) 21.74 to 1.91], presence of lymphatic/vascular invasion [OR 4.95, CI (14.50 to 1.69)], infiltrative margin [OR 9.87 CI (37.44 to 2.60)] and high MIB-1 index [OR 8.39, CI (33.47 to 2.10)]. Two subsets had a very high risk of ALNMs: I) tumour size > 2 cm, with lymphatic/vascular invasion and infiltrative margin; 26 (89.66%) of 29 patients of this subgroup had ALNMs, and (II) tumour size > 2 cm, with lymphatic/vascular and high MIB1 index.; eight of the nine (89%) patients of this subgroup had ALNMs. We could also identify a two-variable model with a very low risk of ALNMs constituted by tumour with circumscribed margin and low MIB-1 index. Of the 19 patients showing these features, only 1 (5.26%) had ALNMs. Therefore, pathological features of the primary tumour can help to assess the risk for ALNM in invasive breast carcinoma. Such risk assessment might avoid regional surgical overtreatment.

Routinely available indicators of prognosis in breast cancer

Diagnosis coupled with prognostication is the challenge for and charge of the pathologist. In this time of rapidly developing basic knowledge and increasing sophistication in the evaluation of prognostic information, there has also been an important re-evaluation of the validity, reliability, and relevance of classic histopathology. Also, the precision of and criteria for evaluating tumor size and status of regional lymph nodes is under study. Our emphasis in this review is tissue pathology and further, its practical relevance to patient management. Histopathology remains the basis of diagnosis universally; the addition of other elements will increase precision of prediction, particularly of responsiveness to individual therapies. Histologic grade may be integrated to substratify high and low stage cases into prognostically more useful subsets. Histologic types also interact with size and nodal status to predict patients with excellent prognosis. Further refinement of these parameters may occur by analysis within clinical, pathologic, or therapeutic subsets.

Evaluating mitotic activity in canine and feline solid tumors: standardizing the parameter

Three different methods for evaluating mitotic activity (mitotic count, mitoses/area, mitotic index) were applied to different types of canine and feline solid tumors to determine the method that is most objective and correlates best with other parameters of cell proliferation. Mitotic activity was evaluated on toluidine blue stained histological sections. Slides stained with histochemical (AgNOR proteins) and immunohistochemical (MIB1, PCNA) markers of cell proliferation were available for each case. Quantitation of mitotic activity and cell proliferation parameters was performed with an image analyzer. Mitotic activity assessment was compared with cell proliferation indices and its ability to discriminate tumors grouped on histologically based criteria including the histological type, malignant or benign characteristics, and grade. A significant correlation by linear regression analysis with other parameters assessing cell proliferation revealed that mitotic index correlated 1000% and mitoses/area and mitotic count correlated 40% of the time. In discriminating the proliferative activity of tumors grouped by histological criteria, mitotic index and mitotic count revealed 1000% concordance with the other parameters of cell proliferation, while mitoses/areas showed 80% concordance.

Cathepsin D in host stromal cells is associated with more highly vascular and aggressive invasive breast carcinoma

AIMS

To determinate the relationship between tumoral angiogenesis and cathepsin D (CD) expression in tumour and host stromal cells of invasive breast carcinoma, and to examine its association with classical prognostic factors such as lymph node status, histological grade, tumour size, mitotic rate, peritumoral lymphovascular invasion and oestrogen receptor (ER) status.

METHODS AND RESULTS

Sections from 102 invasive breast carcinoma were cut from the archival formalin-fixed, paraffin-embedded tissue blocks and stained using immunohistochemistry for the endothelial cell adhesion molecule (CD31) and CD. Microvessel density was assessed by counting vessels in the three most vascular areas at x400 field. The counts were expressed as the highest counts within any x400 field. The evaluation of immunostaining for CD was performed separately in both the parenchymal and stromal cells. Microvessel density was correlated positively with histological grade and peritumoral lymphovascular invasion, and correlated inversely with ER status. Positive CD staining of tumour cells was more frequent in positive ER tumours and was not significantly associated with the other classical prognostic factors. However, moderate to strong staining of host cells was correlated with higher histological grade, higher mitotic index and lack of ER protein. There was a statistically significant association between CD expression of host stromal cells and higher vessel count.

CONCLUSIONS

CD in host stromal cells is associated with more aggressive tumours and with a higher intratumoral microvessel density. Evaluation of CD in combination with angiogenic activity may be of some help in more accurately predicting the biological behaviour of breast carcinoma.

Age-related changes on parameters of experimentally-induced liver injury and regeneration

Age-dependent changes related to liver injury and regeneration were studied in rats aged 2, 12, and 30 months in a time period of 96 hr following a sublethal dose of thioacetamide (6.6 mmoles/kg body wt). Serum aspartate aminotransferase activity increased earlier in young rats, but the severity of injury was higher in those aged 12 months when compared to young and to old. Microsomal hepatocyte FAD monooxygenase activity was induced earlier in 2-month-old rats following intoxication and the increase was significantly lower both in the youngest and in the oldest groups when compared to adults. As a parameter of hepatocellular postnecrotic regeneration, DNA synthesis (2C --> 4C) was evaluated. The population of hepatocytes in S phase peaked more sharply and earlier in young rat hepatocytes, and was 8 to 12 times higher than the initial in hepatocytes from 2- and 12-month-old rats, while the rise was only 3 times in the oldest group. At 96 hr of intoxication the restoration towards normal in all these parameters was complete in young, incomplete in adult, and slightly detected in the oldest. Serum proliferative activity, assayed on mouse NIH 3T3 fibroblast cultures, increased preceding the necrosis and this increase was higher in 2- and 12-month-old (171% and 224%, respectively), while in the oldest the increase was only 110%. This mitogenic activity decreased in all groups during necrosis, showing a second peak, nondetectable in rats aged 30 months, parallel to regeneration. Serum TNFalpha level was absent in untreated animals and increased markedly following intoxication, the highest values being recorded at 72 hr of intoxication in serum from rats aged 12 months (347 +/- 30 pg/ml) and the lowest at 30 months (4.1 +/- 0.3 pg/ml). The serum ability to induce nitric oxide synthase activity on peritoneal macrophages ex vivo showed significant time- and age-dependent changes in nitric oxide release: a decrease throughout necrosis and an increase during regeneration. We conclude that the main age-related changes in the sequenced process of liver injury and regeneration are the delayed response in the development of cell killing and regeneration and the decreased regenerative ability, which significantly delays the restoration of liver function.

Morphometric grading in breast cancer: thresholds for mitotic counts

Three hundred sixty-four cases of invasive ductal breast cancer diagnosed during the years 1988 to 1991 were analyzed to determine quantitative thresholds for mitotic activity. Mitotic counts were calculated in each sample and expressed as standardized mitotic index (SMI) and mitotic activity index (MAI). Based on Kaplan-Meier curves, univariate and multivariate analysis of Cox's regression, and maximum efficiencies of ROC analysis, optimal thresholds were determined on the basis of survival and recurrence of disease. In our material, with a follow-up time of 5 years 9 months, we found two thresholds--a lower and a higher--for both SMI (17 mitoses/mm2 and 32 mitoses/mm2) and MAI (13 mitoses/10 HPF and 35 mitoses/10 HPF). The thresholds were the same in the whole material and in subgroups divided according to the patients' age and axillary lymph node status at the time of diagnosis, and tumor size. The thresholds clearly separated patients with favorable, intermediate, and unfavourable outcome of disease. In our material, the risk of breast cancer death associated with the determined thresholds (ranging from 4.7 to 3.8) clearly exceeded those of menopausal status, axillary lymph node status and tumor size. The risk of breast cancer death associated with the determined thresholds was still emphasized in the groups of premenopausal and axillary lymph node-negative patients, and with tumor size less than 2 cm in diameter (risk ratios, 11.8, 6.0, and 6.7, respectively). The results suggest that the presented quantitative thresholds could be applied in grading of invasive ductal breast cancer.

Correlation between mitotic and Ki-67 labeling indices in paraffin-embedded carcinoma specimens

The mitotic index (MI) and the Ki-67 labeling index (LI) are both understood to measure cellular proliferation, but their relationship is poorly defined. We determined the mitotic index in hematoxylin and eosin-stained paraffin sections of 189 consecutive carcinomas and performed immunohistochemistry on sections from the corresponding blocks using the Ki-67-specific monoclonal antibody Ki-S5. The distributions of MI and LI in the entire series were clearly different, the former fitting a Poisson function in contrast to a broad-tailed unspecific distribution of the latter. Both indices were closely correlated in mammary carcinomas and non-small cell lung cancers, and to a slightly lesser extent in colorectal adenocarcinomas. No significant association was found in small cell lung cancers. In squamous cell carcinomas, the two parameters were inversely correlated. A good agreement between MI and LI values was observed in well-differentiated and moderately well-differentiated cancers regardless of their histological type, whereas in poorly differentiated carcinomas the correlation was not significant. We conclude that MI and LI measure different proliferation characteristics. Their relationship appears to depend on the tumor type and the degree of differentiation. Rather than artifacts due to processing or evaluation techniques, specific differences in cell cycle kinetics are likely to account for these discrepancies.

Survival analysis of 200 pulmonary neuroendocrine tumors with clarification of criteria for atypical carcinoid and its separation from typical carcinoid

Neuroendocrine tumors of the lung embrace a spectrum from low-grade typical carcinoid (TC), intermediate-grade atypical carcinoid (AC), and high-grade categories of large cell neuroendocrine carcinoma (LCNEC) and small cell carcinoma (SCLC). We studied 200 neuroendocrine lung tumors to critically evaluate the Arrigoni histologic criteria for AC using statistical analysis to delimit more rigorously an intermediate survival for AC between TC and the high-grade tumors of LCNEC and SCLC. Histologic features that might predict prognosis were used for Kaplan-Meier and Cox proportional hazards survival analysis, and an optimal mitotic range for AC was calculated. The optimal mitotic range for AC was 2 to 10 mitoses per 2 mm2 of viable tumor (10 high-power fields). Based on this finding, we collapsed mitoses into three categories (< 2; 2-10; > or = 11) and performed Cox multivariate analysis for all 200 neuroendocrine tumors. Mitotic counts were the only independent predictor of prognosis. Based on this analysis, we propose that AC be defined as a tumor with neuroendocrine morphology, mitotic counts between 2-10 per 2 mm2 of viable tumor (10 high-power fields), or coagulative necrosis. Using these criteria, the 200 neuroendocrine tumors were classified as 51 TC, 62 AC, 37 LCNEC, and 50 SCLC. The 5- and 10-year survival was 87% and 87% for TC, 56% and 35% for AC, 27% and 9% for LCNEC, and 9% and 5% for SCLC, respectively. After stratification for stage, survival for AC was significantly worse than for TC (p < 0.001); for LCNEC and SCLC it was significantly worse than for AC; but the survival for LCNEC was no different than that for SCLC.

Necrogenic and regenerative responses of liver of newly weaned rats against a sublethal dose of thioacetamide

The hepatocellular necrogenic and regenerative responses of newly weaned rats (21 days old) to a sublethal dose of thioacetamide (6.6 mmol kg-1) were studied in comparison to adult (6-month old rats), in terms of liver injury, antioxidant defense systems and cell proliferation. Hepatocellular necrosis, detected by serum aspartate aminotransferase, was less severe in newly weaned rats than in adult animals and was parallel to previous changes in the activity of microsomal FAD monooxygenase system responsible for thioacetamide biotransformation. Liver damage in hepatocytes from newly weaned rats was also detected by the decreased levels of glutathione and protein thiol groups (47%, p < 0.001 and 52%, p < 0.001 vs. untreated, respectively) and by the enhanced malondialdehyde production (334%, p < 0.001) and glutathione S-transferase activity (384%, p < 0.001). No significant differences were detected in these values when compared to adults. Changes in cytosolic and mitochondrial superoxide dismutase and catalase activities in hepatocytes from newly weaned rats at 24 h, following thioacetamide (49%, p < 0.001; 50% and 53%, p < 0.001 vs. untreated, respectively), were less severe against those in adult hepatocytes at 48 h of intoxication, and the increases in glutathione peroxidase and glutathione reductase activities were significantly lowered: 25% (p < 0.001) and 41% (p < 0.001), respectively. Post-necrotic DNA synthesis in hepatocytes from newly weaned rats peaked at 48 h of intoxication, while in adults a more intense peak appeared at 72 h preceded by a sharp decrease in tetraploid population. These differences indicate that the lower necrogenic response against the same dose of thioacetamide in newly weaned rats may be due to the lower rate of thioacetamide biotransformation and to the earlier onset of cell division. Accordingly, the growing liver from newly weaned rats presents advantages against the necrogenic aggression of thioacetamide, first, because the diminished activity of its specific microsomal detoxification system, and second because the earlier increase in the proliferative response prevents the progression of injury permitting an earlier restoration of liver function.

Cellular proliferation in breast ductal infiltrating carcinoma. Correlation with clinical and histopathological variables

To evaluate four methods to study cellular proliferation (mitotic count, mitotic index, PCNA and MIB1) in a series of breast ductal invasive cancer NOS, and the possible correlations between these different methods and other pathological variables, we studied 110 ductal invasive carcinomas NOS specimens. Mitoses per 1000 tumor cells and per 10 HPF, and immunostaining for PCNA and MIB1 were evaluated. Other accepted prognostic factors such as tumor size, histologic grade, estrogen and progesterone receptors measured by immunostaining and axillary status were obtained. Correlation between the four methods to evaluate cellular proliferation and these other variables was performed. Mitotic count, mitotic index, PCNA and MIB1 showed a good rate of correlation (r = 0.71-0.53, p < 0.05), with the exception of MIB1-mitotic index which was weak (r = 0.38, p < 0.05). A strong association between cellular proliferation, with independence of the method applied, and histologic grade, ER and PR was obtained. No association was observed with tumor size and lymph node involvement. In conclusion, there was a strong correlation between the four methods to evaluate cellular proliferation. Mitotic count (per 10 HPF) and MIB1 show a better correlation with other morphological variables. None of the evaluated methods are associated with the tumor size and axillary status, suggesting that mitotic count is the most accurate method to analyse cellular proliferation in routine practice.

Prognostic value of histopathologic parameters and DNA flow cytometry in squamous cell carcinoma of the pyriform sinus

A retrospective study of a group of 51 patients who underwent surgery for squamous cell carcinoma of the pyriform sinus was performed. Primary tumors and lymph nodes were reviewed histologically. The primary tumors were also examined by flow cytometry for DNA ploidy and cell cycle analysis. Sixteen (33%) of the cases were aneuploid and 64% had a moderate or high S-phase fraction. The overall 3-year survival rate was 49% (25/51). In the univariate analysis, tumor size, lymphatic invasion, inflammatory infiltrate, presence of lymph node metastases, clinical and histologic N status, size and number of lymph nodes involved, and presence of extracapsular extension all correlated with survival. When multivariate analysis was used, the only independent prognostic factors were tumor size, lymphatic invasion, and histologic N status. Ploidy and S-phase fraction did not contribute further prognostic information.

Obvious peritumoral emboli: an elusive prognostic factor reappraised. Multivariate analysis of 1320 node-negative breast cancers

This study was conducted to determine the prognostic influence of obvious peritumoral vascular emboli as prospectively determined by a simple routine slide examination in patients with operable node-negative breast cancer. Obvious peritumoral emboli (OPE) were defined by the presence of neoplastic emboli within unequivocal vascular lumina (including both lymphatic spaces and blood capillaries) in areas adjacent to but outside the margins of the carcinoma. OPE were assessed routinely on 5 microns thick haematoxylin and eosin-stained sections for each of 1320 primary operable node-negative breast cancers from 1975 to 1992 at our institution. OPE and other prognostic variables (tumour size, SBR grade, oestrogen and progesterone receptor status) were correlated to overall survival (OS) and metastasis-free interval (MFI) by means of univariate and multivariate analysis with a median follow-up of 103 months. OPE were found in 19.5% of tumours. In univariate analysis, OPE were related to tumour size (P = 6.3 x 10(-5)) and histologic grade (P = 4.9 x 10(-7)). Statistically significant correlations were found with OS (P = 4.6 x 10(-5)) and MFI (P = 6.4 x 10(-9)). Furthermore, in multivariate analysis, OPE was an independent prognostic variable, the most predictive factor for MFI (P = 7.7 x 10(-7)) before tumour size and grade, and was second after tumour grade for OS (P = 0.002). This study on a large unicentric series and with a long follow-up confirms the prognostic significance of vascular emboli in patients with operable node-negative breast carcinoma. Importantly, vascular emboli were found to be accurately detectable by a simple routine and non-time-consuming method. Therefore, such obvious vascular emboli should be considered as an important cost-effective, prognostic variable in patients with node-negative breast carcinoma.

Prognostic significance of DNA ploidy and proliferative index (MIB-1 index) in gastrointestinal stromal tumors

The DNA content and proliferative index of 61 gastrointestinal stromal tumors (GIST) were measured by image analysis and correlated with the lesion's clinicopathological features and patient's survival. DNA analysis was performed on cytospin single-cell preparations obtained from the paraffin-embedded tissue blocks. MIB-1 was the proliferation marker used on paraffin sections. DNA aneuploidy was detected in 12 tumors (18%), and high MIB-1 index (>22%) in 12 lesions (18%). DNA aneuploidy and high MIB-1 index statistically correlated with high mitotic rate (> or = 5 x 10 high-power field [HPF]) (P < .001) and with the presence of necrosis (P < .05). The patient's survival was significantly correlated with DNA ploidy (P < .01), MIB-1 index (P < .00001), mitotic rate (P < .00001), presence of necrosis (P < .0001), and size of the tumor (P < .01). Multivariate regression analysis showed that only MIB-1 index was an independent parameter in predicting the clinical outcome for patients with GIST. The mitotic rate was the only other independent prognostic factor when MIB-1 index was not allowed to enter the model.

p53 protein expression in ductal carcinoma in situ (DCIS) of the breast

Abnormalities in p53 gene expression have been implicated in many inherited and sporadic forms of malignancies in humans. Immunohistochemical staining using monoclonal antibody D0-7 for the p53 protein expression was performed in 81 cases of pure DCIS, 14 benign breast lesions and 2 cases with normal breast tissue. Expression of p53 protein was detected in 15 (18.5%) cases of pure DCIS. Thirteen (25%) of the 52 comedo type DCIS showed p53 protein expression compared with 2 (6.9%) of the 29 non-comedo types (P < 0.02). p53 protein expression was also associated with high nuclear grade (P < 0.001) and high mitotic index (P < 0.05). The pattern of p53 protein staining was diffuse in one comedo type DCIS, regional in 6 comedo types, and focal in the remaining 8 cases (6 comedo type and 2 micropapillary type DCIS). The patient with comedo type DCIS showing diffuse staining has a family history of breast cancer in the first and second degree relatives (sister and maternal aunt). Clinical follow-up data was available in 52 cases. Follow-up period ranged from 9 to 55 months. Three patients, who were primarily treated by local excision, have had a documented local recurrence in the form of residual tumor within a short interval of 5 to 11 months. In all these three patients both the original and the recurrent tumors are negative for p53 protein expression. The difference in the local recurrence rate between p53 positive (0/15) and p53 negative (3/37) cased does not reach statistical significance (p > 0.05). We interpret that the local tumor recurrence in these three cases within a short period after primary excision is due to the presence of residual tumor at the excision site and is independent of the p53 gene alteration. It is concluded that p53 protein expression in DCIS is associated with comedo subtype, high nuclear grade, and high mitotic index, and is a promising new parameter to evaluate the cellular biology and prognosis of DCIS.

Standardized mitotic counts in breast cancer. Evaluation of the method

Twenty-one pathologists and technicians participated in a study evaluating the variation present in mitotic counts for prognostication of breast cancer. The participants counted the mitotic figures in 20 breast cancer samples from ten high power fields (mitotic activity index, MAI, giving the results in mitotic figures per 10 fields) and also made a correction for field size and area fraction of the neoplastic epithelium to get the standardized mitotic index (volume fraction corrected mitotic index, or M/VV index, giving the result in mitotic figures per square mm of neoplastic epithelium). The difference in variation between the two methods was not big, but the standardized mitotic index (SMI) showed consistently smaller variation among all participants and different subgroups. Experienced pathologists had the highest variation in mitotic counts, and specially trained technicians, the lowest. The efficiency of the mitotic counts in grading (the grading efficiency) was used to evaluate the mitotic counts. In groups without special training for mitotic counts the mean grading efficiency was lower (experienced and training pathologists both on average had the potential to grade 88% of the cases correctly) than in the group specially trained for the purpose (trained technicians had the potential to grade 95% of the cases correctly). Among the specially trained technicians, the grading efficiency was of the same magnitude as the grading efficiency achieved in determining the S-Phase fraction of cells from paraffin embedded breast cancers by flow cytometry in different laboratories. The results suggest that special training is helpful in making mitotic counts more reproducible, and that in trained hands, the mitotic counts give results comparable to more sophisticated methods of determining proliferative activity in breast cancer.

MIB-1 staining index and peritumoral brain edema of meningiomas

BACKGROUND

Growth rates and tumor aggressiveness of meningiomas are thought to be closely related to brain edema development. However, histopathologic data alone are not consistently accurate predictors of the behavior and clinical course of a meningioma.

METHODS

The authors examined 57 histologically proven intracranial meningiomas to identify factors, including growth fractions determined by MIB-1 immunostaining, that may influence the development of meningioma-associated peritumoral brain edema. There were 54 benign, 2 atypical, and 1 anaplastic meningiomas. The MIB-1 staining index (SI) percentage was defined as the number of MIB-1 positive cells divided by the total number of tumor cells in a 1.037-square millimeter area on the slide. The extent of peritumoral brain edema was determined using preoperative magnetic resonance imaging. The extent of edema was classified as Grade 0,1, or 2 (GR0, GR1, or GR2), in order of increasing severity.

RESULTS

The MIB-1 SIs of the 57 cases ranged from 0.06-6.8% (median, 0.80%). There were 26 GR0, 20 GR1, and 11 GR2 edema cases. The MIB-1 SI rose in order of increasing edema severity. There was a statistically significant correlation between the MIB-1 SI and the extent of brain edema (P<0.0001), and also between the tumor size and the extent of brain edema (P=0.001). Meningothelial and atypical/anaplastic meningiomas were associated with peritumoral brain edema more often than any other subtype (P<0.005).

CONCLUSIONS

Growth fractions, as determined by MIB-1 immunostaining, rise with increasing severity of peritumoral brain edema, indicating a close relationship between tumor aggressiveness and edema development.

Hepatic stimulator substance administration enhances regenerative capacity of hepatocytes in cadmium-pretreated partially hepatectomized rats

The liver is of central importance in the metabolism of essential and toxic metals such as cadmium (Cd). Cd pretreatment suppressed the regenerative capacity of hepatocytes, which normally occurs 24 hr after partial hepatectomy, due to the inhibition of the activity of the enzyme thymidine kinase. The effect of hepatic stimulator substance (HSS) administration (10, 20, and 40 mg protein/kg body weight) on hepatocyte proliferation was investigated in Cd-pretreated partially hepatectomized rats. HSS administration partly restored the suppressed hepatocyte DNA biosynthesis in Cd-pretreated partially hepatectomized rats. The hepatocyte mitotic activity and the percentage of proliferating cell nuclear antigen-positive nuclei were in accordance with the liver proliferative status. The administration of HSS did not affect in a statistically significant manner the activity of the enzyme thymidine kinase in Cd-pretreated partially hepatectomized rats. It is suggested that the administration of HSS ameliorates the diminished hepatocyte regenerative response to partial hepatectomy in this model of acute liver injury, due to Cd intoxication.