Argyrophilic Nucleolar Organizer Regions Research Articles

Clinical evaluation of canine mast cell tumor treatment between combined vinblastine and prednisolone and single prednisolone

Thirty three dogs having cutaneous mast cell tumors (MCT) were divided into two groups; group 1 had 23 dogs that were treated with vinblastine and prednisolone and group 2 had 10 dogs that were treated with prednisolone. Evaluation of the 33 pre- and post-treated tissue samples was performed on their clinical stages, histopathological features, expression of proliferative markers such as argyrophilic nucleolar organizer regions (AgNORs), proliferative cell nuclear antigen (PCNA) and Ki-67 and clinical response. All cases were diagnosed as MCT grade II without post-treatment changes in histopathological grade. An increase of uniform nucleus, stroma but a decrease of cytoplasm, the number of visible nucleolus, intralesional vascularization, eosinophilic aggregation, and the mean of mitotic index (pretreatment = 1.6 cells/HPF, post-treatment = 1.1 cells/HPF) was observed in the post-treated samples of both groups. With regard to the clinical evaluation, 18 dogs (78.2%) were partially responsive and the rest (21.8%) were stable in group 1 while five dogs (50%) were partially responsive, three dogs (30%) were stable, and the remaining two dogs (20%) were progressive in group 2. The median survival time of the group 1 cases was 101 days and for the group 2 cases was 175 days. In addition, mean ± standard deviations of AgNORs (dots/cell), PCNA (%), and Ki-67 (%) were 1.83 ± 0.4, 18.67 ± 9.25, and 6.86 ± 7.23 in the pretreatment group 1 and 1.59 ± 0.3, 12.4 ± 7.15, and 1.9 ± 1.35 in the post-treatment group 1, respectively. Mean ± standard deviations of AgNORs, PCNA and Ki-67 were 1.83 ± 0.42, 18 ± 20.01 and 6.74 ± 5.42 in the pretreatment group 2 and 1.67 ± 0.28, 6.28 ± 5.59 and 2.3 ± 1.55 in the post-treatment group 2, respectively. All proliferative markers decreased differently statistically after treatment (P < 0.05). In conclusion, the MCT dogs treated with vinblastine and oral prednisolone and single oral prednisolone were shown to have a decrease in histopathological malignancy characteristics which included AgNORs, PCNA, Ki-67 indices.

Correlation between the Histopathological Diagnosis by AgNOR Count and AgNOR Area in Canine Mammary Tumors

Mammary tumors are the most common type of tumor in female dogs. The histopathological diagnosis is usually made by a hematoxylin-eosin (HE) staining of the tumor, which then requires a pathologist's judgment for assessment of malignancy. The purpose of this study was to investigate an alternative silver staining of some argyrophilic nucleolar organizer regions (AgNOR) for improving the diagnostic accuracy with mammary tumors. There is a correlation between the histopathological diagnosis by AgNOR count and AgNOR area in canine mammary tumors. Seventy-three canine mammary tumors from 33 female dogs. The AgNOR staining was evaluated retrospectively in 73 canine mammary tumors with a parallel HE staining as a "Gold Standard." Both a quantitative manual counting method and a qualitative computerized morphometric method were tested. The result from both methods indicated a clinically relevant difference in the mean values of the AgNOR in the following 4 categories: malignant, benign, hyperplastic, and normal mammary tissue. The counting method was superior, with 89% of the cases given a correct diagnosis of a malignant or a nonmalignant canine mammary tumor. The 2 methods were then compared to test their ability to classify the tumors correctly. Again, the counting method was the most reliable method, with a sensitivity of 80% and a specificity of 76% when the upper 50% of the AgNOR counts were presumed malignant. The results indicated that an AgNOR test could be an aid to pathologists as a prognostic indicator or to assist them in deciding between a benign or a malignant diagnosis in questionable cases.

Prognostic value of a proliferation index including MIB1 and argyrophilic nucleolar organizer regions proteins in node-negative breast cancer

This study was designed to evaluate a cell proliferation marker, including the percentage of cycling cells (MIB1), and the duration of the cell cycle (assessed by argyrophilic nucleolar organizer regions proteins [AgNORs] measurement). We included 90 patients with invasive node-negative breast cancer. None received chemotherapy. With the help of a double-staining technique, a proliferation index (PI) was determined by multiplying the percentage of MIB1-positive cells by the mean area of the AgNORs present in those MIB1-positive cells. PI was evaluated for its impact on overall survival (OS) and disease-free survival (DFS). We demonstrated that PI was correlated to OS. For DFS, it conserved its high prognostic value only in univariate analysis. The global amount of AgNORs was more discriminative for DFS. PI and AgNOR quantification supplied additional prognosis information in node-negative patients, and we propose to integrate them in further studies.

Argyrophilic nucleolar organizer regions in inflammatory, premalignant, and malignant oral lesions: A quantitative and qualitative assessment

Argyrophilic nucleolar organizer regions (AgNORs) have found widespread application in the past, especially in tumor histopathology. This study was undertaken to evaluate the significance of various AgNOR parameters and to assess their role in differentiating hyperplastic, premalignant, and malignant lesions. The study sample consisted of archival biopsy specimens of ten squamous cell carcinomas, ten premalignant lesions, and five inflammatory lesions. Two biopsies from normal mucosa acted as control. AgNORs were assessed both quantitatively and qualitatively. The data were analyzed using Student's independent t-test, one-way analysis of variance (ANOVA), and multiple range test (Tukey-HSD). Quantitatively significant difference existed in the number of AgNORs between the normal mucosa, inflammatory lesions, and carcinomas, but the premalignant lesions failed to differ significantly from the normal mucosa. The number of AgNORs was found to be related to epithelial proliferation. Qualitatively, in terms of size, shape, and pattern of distribution, the normal mucosa and inflammatory lesion were alike, but the premalignant and malignant lesions differed significantly from the normal, with a marked degree of AgNOR pleomorphism being observed in carcinomas. AgNOR quantity is strictly proportional to the proliferative activity of the cell and does not necessarily indicate malignancy. It is the qualitative characteristics of AgNOR that help to differentiate hyperplastic, premalignant, and malignant lesions.

Argyrophilic Nucleolar Organizing Regions and Ki67 Equally Reflect Proliferation in Fine Needle Aspirates of Normal, Hyperplastic, Inflamed, and Neoplastic Canine Lymph Nodes (n = 101)

Background: The count of argyrophilic nucleolar organizing regions (AgNOR) has been considered a useful variable that reflects cellular proliferation in canine lymph nodes, but it has not been compared with other markers of proliferation. Hypothesis: Ki67 and AgNORs are equally useful as markers of tissue proliferation in fine needle aspirates of canine lymph nodes. Animals: A total of 101 dogs.Material and Methods: Prospective, observational study of a convenience sample of dogs. Two smears were prepared for a May‐Gruenwald‐Giemsa stain and a Ki67/AgNOR double stain. In addition, CD3/CD79a immunostaining was performed when cytologic examination revealed a lymphoma. The dogs were grouped as normal (n = 26), reactive hyperplasia (n = 25), lymphadenitis (n = 31), and lymphoma (n = 19), based on the physical examination and the cytologic findings. The AgNOR count/cell, AgNOR area/cell and the percentage of cells staining positive for Ki67 were evaluated in 100–167 cells (median, 113 cells) by using automatic image analysis. Results: Mean (SD) AgNOR counts/cell were 1.36 6 0.19 in normal dogs, 1.55 ± 0.26 in lymphadenitis, 1.65 ± 0.32 in reactive hyperplasia, and 3.67 ± 1.08 in lymphoma. The percentage of Ki67 positive cells was 2.67 ± 0.99% in normal lymph nodes, 5.04 ± 3.34% in lymphadenitis, 5.36 ± 2.14% in reactive hyperplasia, and 30.2 ± 10.8% in lymphoma. All variables were significantly higher in dogs with lymphoma compared with the other groups (P &lt; .0001). The sensitivity and the specificity of the AgNOR count for diagnosing lymphoma were 95 and 96% at a cutoff value of .2.04 AgNORs/cell. The cutoff value for the Ki67 positive cells was .10.40% (sensitivity, 95%; specificity, 98%).Conclusion and Clinical Importance: The results indicated that both AgNOR and Ki67 counts were good diagnostic tools for assessment of proliferation in aspirates of canine lymph nodes.

Molecular Cytogenetics of Blind Mexican Tetra and Comments on the Karyotypic Characteristics of GenusAstyanax(Teleostei, Characidae)

Astyanax mexicanus is popularly known as the blind Mexican tetra or blind cave tetra and has been extensively studied regarding various aspects of its biology and genetics. Despite the identification of linkage maps of genes related to quantitative trait loci by many recent studies, only its diploid number was known from a cytogenetical point of view. With the purpose of providing a base for comparative studies and for the elucidation of physical maps for the species, cytogenetical studies were performed in a group of 10 blind specimens from Mexico. All the individuals presented 2n = 50 chromosomes and a karyotypic formula composed of 8M + 18SM + 12ST + 12A. A few specimens presented one or two B microchromosomes of the acrocentric type. Although simple argyrophilic nucleolar organizer regions (Ag-NORs) were evidenced, fluorescence in situ hybridization (FISH) with an 18S rDNA probe evidenced eight sites, and six sites were observed with a 5S rDNA probe. Little constitutive heterochromatin was observed, mainly related with the Ag-NORs and located close to the centromeres, including those from the B microchromosomes. A few pericentromeric heterochromatin regions were mainly constituted by GC, including the one from the Ag-NOR. Very subtle markings were observed by FISH with an As-51 satellite DNA probe. The B microchromosome did not present ribosomal genes or satellite DNA. Chromosomal aspects of the genus Astyanax are discussed.

Cellular Proliferation in Canine Cutaneous Mast Cell Tumors: Associations withc-KITand Its Role in Prognostication

Canine cutaneous mast cell tumor (MCT) is a common neoplastic disease in dogs. Due to the prevalence of canine MCTs and the variable biologic behavior of this disease, accurate prognostication and a thorough understanding of MCT biology are critical for the treatment of this disease. The goals of this study were to evaluate and compare the utility of the proliferation markers Ki67, proliferating cell nuclear antigen (PCNA), and argyrophilic nucleolar organizing region (AgNOR) as independent prognostic markers for canine MCTs and to evaluate the use of these markers in combination, as each marker assesses different aspects of cellular proliferation. An additional goal of this study was to evaluate the associations between cellular proliferation and c-KIT mutations and between cellular proliferation and aberrant KIT protein localization in canine MCTs. Fifty-six MCTs treated with surgical excision alone were included in this study. Each MCT was evaluated for Ki67 expression, PCNA expression, and KIT protein localization using immunohistochemistry; for AgNOR counts using histochemical staining; and for the presence of internal tandem duplication c-KIT mutations using polymerase chain reaction amplification. In this study, increased Ki67 and AgNOR counts were both associated with significantly decreased survival. On the basis of these results, we recommend that the evaluation of cellular proliferation, including evaluations of both Ki67 expression and AgNORs, should be routinely used in the prognostication of canine MCTs. Additionally, the results of this study show that MCTs with aberrant KIT protein localization or internal tandem duplication c-KIT mutations are associated with increased cellular proliferation, further suggesting a role for c-KIT in the progression of canine MCTs.

Canine Subcutaneous Mast Cell Tumour: Diagnosis and Prognosis

The aim of this study was to characterize the pathology and clinical outcome of the subcutaneous variant of canine mast cell tumour. Fifty-three cases satisfying the inclusion criteria were selected from the pathology archive of the College of Veterinary Medicine, University of Tennessee. Referring veterinarians provided information on outcome. These dogs had a median age of 9 years (range 3-17 years). After characterizing tumours histologically, nuclear expression of proliferating cell nuclear antigen (PCNA) and Ki67 (MIB-1 clone) was determined immunohistochemically and mast cell origin was confirmed with c-Kit staining. Counts of argyrophilic nucleolar organizer regions (AgNOR) were determined by silver staining. Nuclear labelling was counted in 100 tumour cells. Margins were recorded as incomplete in 66% of dogs, and metastases occurred in 6% of dogs. The estimated minimum mean survival time from date of diagnosis was 1199 days, ranging from 55 to >1780 days. The median scores from immunohistochemical labelling were PCNA 0.05 and Ki67 0.03 per 100 tumour cells. The median score for AgNOR staining was 1.25 per 100 tumour cells. The patterns of c-Kit expression included membranous labelling in 20 tumours, stippled cytoplasmic labelling in 23 tumours and diffuse cytoplasmic labelling in 10 tumours. Age (r=-0.61, P=0.14) and AgNOR score (r=-0.58, P=0.17) had moderate, but non-significant, negative associations with survival. PCNA (r=-0.32, P=0.47), Ki67 (r=-0.22, P=0.64) and c-Kit immunolabelling was not associated with survival. The subcutaneous variant of canine mast cell tumour is distinct in having features of intermediate histological grade and extended mean survival times, suggesting a slightly better long-term prognosis than for higher grade dermal variants. Expression of nuclear proliferation markers is not associated with outcome.

Studies on argyrophilic nucleolar organizer regions (AgNORs) in a spontaneous mammary gland ductal carcinoma of a captive rhesus monkey

A spontaneous mammary gland ductal carcinoma was diagnosed in a 13-year-old female captive rhesus monkey ( Macaca mulatta). The expression of argyrophilic nucleolar organizer regions (AgNORs) was studied to investigate the correlation between the histologic invasiveness and cell proliferation activity assay for predicting the biologic behavior of this tumor type. The results of this study show that the AgNOR size in tumor cells reflect the degree of malignancy when compared with the pattern of peripheral blood lymphocytes of the same individual. This is the first study showing a significant AgNOR feature of a malignant breast tumor in a rhesus monkey and it longs to provide additional diagnostic tool in tumor pathology.

Quantitative analysis of argyrophilic nucleolar organizer regions and epidermal growth factor receptor in ameloblastomas

The aim of this study was to evaluate the proliferation activity by means of the quantification of the argyrophilic nucleolar organizer regions (AgNORs) and the patterns of expression of the epidermal growth factor receptor (EGFR) in ameloblastomas. The methods of evaluation included the H/E stain for the morphologic analysis, the silver impregnation technique for quantification of the AgNORs and the immunohistochemical stain with anti-EGFR antibody in 11 cases of ameloblastoma. The results did not show a significant statistical difference as per quantification of the AgNORs. The expression of the EGFR on the epithelial islands of ameloblastoma was not uniform, and the location of the expression was also variable. The predominant expression was that of cytoplasm and the islands with an expression of membrane only were rare and generally smaller in size. The tumor presents an irregular growth. Smaller islands are associated with a higher proliferation activity and therefore could be responsible for tumor infiltration.

Comparison of Argyrophilic Nucleolar Organiser Regions (AgNORS) with Proliferating Cell Nuclear Antigen (PCNA) in Different Grades of Transitional Cell Carcinoma of Urinary Bladder

Objective : To Compare Argyrophilic Nucleolar Organiser Regions (AgNORs) pattern with Proliferating nuclear antigen (PCNA) in different grades of transitional cell carcinoma. Design : Descriptive and Comparative study. Material and Methods : A total of fifty transurethrally resected bladder tumour samples (TUR BT) were collected from Mayo Hospital, Lahore and Services Hospital, Lahore and processed for H&E, AgNOR stain and PCNA stain. The grading of tumours were made on H&E stain. While AgNOR pattern and PCNA labeling index were recorded for each case. Results : A significant higher proportion of cases (p<0.02) with 3+ AgNOR dispersion were seen in grade III tumours. The AgNOR proliferative index in grade III tumour was significantly higher (p<0.05) as compared with grade II tumours. The cases with AgNOR dispersion of 3+ had significantly higher mean PCNA labeling index (p<0.02) when compared tumours of 2+ AgNOR dispersion. Conclusion : AgNOR and PCNA have significant role in grading of transitional cell carcinoma. The demon-stration of AgNOR dispersion is also a simple and cost effective procedure and could be considered as a substitute for PCNA labeling index. Key words: Nuclear organizer regions, PCNA, Transitional cell carcinoma.

Argyrophilic Nucleolar Organizing Regions and Ki67 Equally Reflect Proliferation in Fine Needle Aspirates of Normal, Hyperplastic, Inflamed, and Neoplastic Canine Lymph Nodes (n &amp;hairsp;=&amp;hairsp; 101)

The count of argyrophilic nucleolar organizing regions (AgNOR) has been considered a useful variable that reflects cellular proliferation in canine lymph nodes, but it has not been compared with other markers of proliferation. Ki67 and AgNORs are equally useful as markers of tissue proliferation in fine needle aspirates of canine lymph nodes. A total of 101 dogs. Prospective, observational study of a convenience sample of dogs. Two smears were prepared for a May-Gruenwald-Giemsa stain and a Ki67/AgNOR double stain. In addition, CD3/CD79a immunostaining was performed when cytologic examination revealed a lymphoma. The dogs were grouped as normal (n = 26), reactive hyperplasia (n = 25), lymphadenitis (n = 31), and lymphoma (n = 19), based on the physical examination and the cytologic findings. The AgNOR count/cell, AgNOR area/cell and the percentage of cells staining positive for Ki67 were evaluated in 100-167 cells (median, 113 cells) by using automatic image analysis. Mean (SD) AgNOR counts/cell were 1.36 +/- 0.19 in normal dogs, 1.55 +/- 0.26 in lymphadenitis, 1.65 +/- 0.32 in reactive hyperplasia, and 3.67 +/- 1.08 in lymphoma. The percentage of Ki67 positive cells was 2.67 +/- 0.99% in normal lymph nodes, 5.04 +/- 3.34% in lymphadenitis, 5.36 +/- 2.14% in reactive hyperplasia, and 30.2 +/- 10.8% in lymphoma. All variables were significantly higher in dogs with lymphoma compared with the other groups (P < .0001). The sensitivity and the specificity of the AgNOR count for diagnosing lymphoma were 95 and 96% at a cutoff value of >2.04 AgNORs/cell. The cutoff value for the Ki67 positive cells was >10.40% (sensitivity, 95%; specificity, 98%). The results indicated that both AgNOR and Ki67 counts were good diagnostic tools for assessment of proliferation in aspirates of canine lymph nodes.

Preventing Liver Metastasis by Resecting the Primary Pancreatic Carcinoma at an Early Stage of Intrapancreatic Transplantation in Hamsters

To determine whether early primary pancreatic tumor resection can prevent liver metastases of intrapancreatic transplantation in a hamster model. Cells from the PGHAM-1 cell line were transplanted into the pancreases of 30 Syrian golden hamsters. A suspension of 5 x 10(6) cells was injected into the splenic lobe of each pancreas. The primary pancreatic tumor was resected in 15 of the hamsters 10 days after transplantation (resection group). Fifteen other animals with transplantation but without resection served as controls (control group). All hamsters were killed 21 days after transplantation. The primary pancreatic tumors were measured for size and volume and examined histologically and immunohistologically for angiogenesis and tumor proliferation. In the resection group, small pancreatic tumors 4.7 +/- 0.94 mm in diameter were found and resected 10 days after transplantation. Neither pancreatic tumors nor liver metastases were found in the resection group at the end of the experiment. All animals in the control group had pancreatic tumors 12.3 +/- 3.29 mm in size, and 11 of 15 (73.3%) had liver metastases. The primary pancreatic tumors in the group with liver metastasis were significantly larger in diameter and volume than those in this group without liver metastasis (p<0.01). In the control group, proliferation of the primary pancreatic tumor, evaluated according to argyrophilic nucleolar organizer region, showed no differences within the pancreatic tumor group. On the other hand, the microvessel density of pancreatic tumors with liver metastases was significantly higher than that of tumors without liver metastases. Our results suggest that 10 days after transplantation, the pancreatic tumors were small in size and volume and ready to proliferate but not yet ready to begin metastasizing through angiogenesis. This is one reason why early resection of the primary tumor prevents liver metastasis.

Morphometry and digital AgNOR analysis in cytological imprints of benign, borderline and malignant serous ovarian tumours

The aim of the study was to determine values of a quantitative morphometry analysis of nuclear characteristics and argyrophilic nucleolar organizer regions (AgNORs) in differential cytodiagnosis of benign, atypically proliferating (borderline) and malignant serous ovarian tumours. Cytological imprints of benign (n = 20), borderline (n = 19) and malignant (n = 20) ovarian serous tumours were analysed. A computerized, digital analysis was used to determine morphometric nuclear features, the number and characteristics of single AgNORs, cluster AgNORs, total AgNOR and AgNOR area/nucleus (relative area) ratio. According to their size AgNORs were classified in three categories. A one-way variance analysis and post hoc test (Scheffé) were used for statistical analysis. The morphometric nuclear analysis showed that benign, borderline and malignant serous ovarian tumours are statistically different (P < 0.001) according to the area and outline, the values being highest in malignant tumours and lowest in the borderline group. Digital analysis of AgNORs in benign, borderline and malignant groups showed that the total AgNOR number increases with progression of the lesion (meaning tumour malignancy) significantly (P < 0.001) between benign and malignant as well as between borderline and malignant serous ovarian tumours (P < 0.001). The progression of the lesion malignancy was accompanied by a significant (P < 0.001) progressive increase of the total and relative AgNOR area per nucleus. The AgNOR size increases from benign to malignant tumours and a statistically significant difference (P < 0.001) was observed in all three groups regarding small and large AgNORs. Combining different markers of morphometric nuclear characteristics and AgNOR values could improve differential cytodiagnosis of benign, borderline and malignant serous ovarian tumours.

Prognostic Significance of Intratumoral Microvessel Density in Canine Soft-Tissue Sarcomas

The prognosis of canine soft-tissue sarcomas (STS) has traditionally been based on histologic grading. We have recently demonstrated the prognostic value of cellular proliferation markers in canine STS. Another method of predicting the behavior of neoplasms is intratumoral microvessel density (IMD), which is a measure of tumor angiogenesis. The prognostic significance of IMD has been documented in many human neoplasms and in a limited number of canine and feline neoplasms. To evaluate the prognostic value of IMD in canine STS, we studied 57 STS and compared IMD with histologic features, histologic grade, cellular proliferation, metastatic propensity, and survival. Using immunohistochemistry, the STS were labeled with anti-factor VIII-related antigen (FVIII-RA) and anti-CD31 antibodies to determine 3 IMD parameters: mean microvessel density, high microvessel density, and microvessel area. Using FVIII-RA and CD31, increasing IMD was statistically associated with increasing histologic grade, necrosis scores, and mitotic scores. Higher FVIII-RA IMD values were significantly associated with higher median argyrophilic nucleolar organizing region (AgNOR) values (as previously investigated) and increased metastatic propensity. Fibrosarcomas appear to be the least vascularized of STS. There is no correlation between IMD and survival. Our results indicate that IMD is of prognostic value for histologic grade, histologic features, cellular proliferation (based on AgNOR), and metastatic propensity of canine STS, specifically when using FVIII-RA as the endothelial marker. Assessing histologic grading, cellular proliferation, and IMD of canine STS at the time of diagnosis could therefore provide better prognostic information for the veterinary clinician.

A statistical model predicting high hepatocyte proliferation index and the risk of developing hepatocellular carcinoma in patients with hepatitis C virus‐related cirrhosis

Incidence of hepatocellular carcinoma in hepatitis C virus-related cirrhosis is 4% per year. Although cost-effective, current screening could be improved. To develop a statistical model including non-invasive parameters able to identify patients at high risk of developing hepatocellular carcinoma. One hundred and fifty-eight patients (73F:85M) with compensated chronic hepatitis C virus liver disease underwent evaluation, including argyrophilic nucleolar organizer regions proliferation index, and were followed up for 56.18 +/- 1.44 months. Fifty-six patients had chronic hepatitis without cirrhosis and low argyrophilic nucleolar organizer regions proliferation index (< or =25%), 65 had hepatitis C virus-related cirrhosis and low argyrophilic nucleolar organizer regions proliferation index and 37 had hepatitis C virus-related cirrhosis and high argyrophilic nucleolar organizer regions proliferation index (>25%). Groups were similar for gender and viral genotype distribution. None of the patients with chronic hepatitis without cirrhosis developed hepatocellular carcinoma, compared with 6.1% of low argyrophilic nucleolar organizer regions proliferation index and 30.6% of high argyrophilic nucleolar organizer regions proliferation index (P = 0.002). By multivariable logistic regression analysis, the following parameters were independently associated with hepatocellular carcinoma development and used for the development of the statistical model: platelets (OR 0.98), gamma-globulins (OR 0.111), alanine aminotransferase/aspartate aminotransferase ratio (OR 0.07), serum ferritin (OR 1.0) and ultrasonographic pattern (coarse OR 2.9, coarse nodular OR 10.12). The statistical model properly allocated 95.9% of patients with low argyrophilic nucleolar organizer regions proliferation index and 72.2% of patients with high argyrophilic nucleolar organizer regions proliferation index. The model, to be validated in large prospective studies, may help tailoring screening according to the risk of hepatocellular carcinoma development.

Association of argyrophilic nucleolar organizing regions, Ki-67, and proliferating cell nuclear antigen scores with histologic grade and survival in dogs with soft tissue sarcomas: 60 cases (1996—2002)

To determine whether argyrophilic nucleolar organizing regions (AgNORs), Ki-67, and proliferating cell nuclear antigen (PCNA) scores were associated with histologic grade and survival in dogs with soft tissue sarcomas (STSs). Retrospective study. 60 dogs with STSs. Medical records were examined and histologic specimens were reviewed. Tissue specimens obtained from archival materials were used to prepare sections for histologic staining for AgNOR and immunohistochemical staining for Ki-67 and PCNA labeling. Follow-up monitoring was obtained by reevaluation or telephone conversations with referring veterinarians or owners. 27 (45%) STSs were grade 1, 23 (38%) were grade 2, and 10 (17%) were grade 3. The mean and median AgNOR, Ki-67, and PCNA scores were determined, and significant positive associations among AgNOR and Ki-67 scores with histologic grade and mitotic score were detected. Fifty-four dogs had adequate follow-up examinations and were included in survival analysis and evaluation of prognostic factors. Overall median survival time was > 1,306 days. Twelve of 54 (22%) dogs died of tumor-related causes. Metastatic disease developed in 8 of 54 (15%) dogs. Results of univariate analysis indicated that increased mitotic score, increased AgNOR score, increased Ki-67 score, incomplete surgical margins, noncurative intent surgery, Ki-67 score greater than the median Ki-67 score, and AgNOR score greater than the median AgNOR score were prognostic factors for decreased survival time. Results of multivariate analysis indicated that increased AgNOR score was the only prognostic factor for decreased survival time. Results suggested that AgNORs and possibly Ki-67 should be routinely evaluated with histologic grading for STSs in dogs.

Mitotic Polyploidization in Trophoblast Giant Cells of the Alpaca

Genome multiplication is a typical feature of trophoblast giant cell (TGC) development in many species. Elevated nuclear DNA contents can be achieved by modified cell cycles with a complete lack of mitosis (endoreduplication) or with incomplete mitoses. The aim of this study is to characterize genome multiplication in the alpaca TGC. Placental tissues of gestation days 150, 264 and 347 (near term) and term placentae were processed for light microscopy and for transmission electron microscopy. Each TGC showed many nuclear profiles. Observation of serial sections revealed that TGCs are truly multinucleate with several highly lobulated nuclei. Feulgen staining showed that TGC nuclei have a higher DNA content than nuclei of other trophoblast cells. The number of argyrophilic nucleolar organizer regions (AgNORs) in nuclear profiles of TGC was between 15 and 100, while other trophoblast cells showed 1 or 2 AgNORs. Large multipolar mitotic figures with maximal diameters of 80 µm were observed in the alpaca placentas on gestation days 264 and 347. No cytokinesis was seen in TGC. The results show that the mode of genome multiplication in the alpaca TGC is mitotic polyploidization. Subsequent acytokinetic mitoses may lead to an accumulation of chromosomes and centrioles in TGC. With increasing ploidy levels, the shape of these polyploidizing mitoses becomes more irregular. The restitution of nuclei after these complex multipolar mitoses is likely to result in the irregular nuclear shape in TGC.

Evaluation of argyrophilic nucleolar organizer region staining in predicting the behavior of meningiomas.

BACKGROUNDThe number of argyrophilic nucleolar organizer regions (AgNOR) correlates with cellular proliferative activity. Comparing non-recurrent, recurrent, atypical and malignant meningiomas we studied the value of the routine applicability of the AgNOR count in the prognostication of this tumor.PATIENTS AND METHODSTwo hundred and thirty-eight meningiomas were reviewed blindly and graded using WHO grading schema. Eighty-one cases were selected and arranged in six groups according to clinical data and grading: 14 benign non-recurrent meningiomas; 14 primary benign recurrent meningiomas and their subsequent benign recurrences; 14 atypical; 11 malignant and 14 spinal meningiomas. Silver-stained slides were prepared and mean, median and standard deviation of AgNOR dots determined.RESULTSThere was a proportionate increase of AgNOR dots with increasing tumor grade. There was a significant difference between benign non-recurrent tumors versus benign recurrent (P<0.0001) and atypical or malignant (P<0.0001) tumors. A difference was also noted between the recurring tumors versus malignant ones (P= 0.002) but no significant difference was seen between recurrent and atypical; atypical and malignant; intracranial and intraspinal; and primary of recurring meningiomas with their subsequent recurrences. A mean AgNOR count of <2.3 could separate benign tumors from atypical or malignant meningiomas with 93% specificity; and 93% of tumors with benign histology had no recurrence potential if their mean AgNOR count was less than 1.8.CONCLUSIONThis study indicates that in meningioma, the AgNOR count has a good correlation with tumor grading and recurrence, which may aid pathologists and clinicians in predicting tumor behavior.

A new scoring system using multiple immunohistochemical markers for diagnosis of uterine smooth muscle tumors

The diagnosis of uterine smooth muscle neoplasms by light microscopy is difficult. Multiple classification schemes have been proposed based on mitotic rate, nuclear atypia, and the presence or absence of necrosis. None of these classification systems has been entirely successful. This study was undertaken to evaluate the use of selected immunohistochemical and histochemical markers in differentiating these tumors, in addition to accepted morphologic criteria. Ten cases of each of the following: leiomyosarcomas (LMS), atypical leiomyomas (AL), cellular leiomyomas (CL) and usual leiomyomas (UL), were classically evaluated for histological diagnosis and were stained for Ki-67 (MIB-1), bcl-2 and p53 using monoclonal antibodies and the avidin-biotin peroxidase method, and argyrophilic nucleolar organizer region (AgNORs). The number of stained cells was counted in the most positively stained region in a 4 mm2 square cover glass mounted on each slide. The mean value was calculated for each group of tumors. The data for Ki-67 (MIB-1), bcl-2, p53 and AgNOR staining respectively, were significantly higher in LMS by comparison to UL, CL or AL. Because many singular cases had superimposed data being difficult to diagnose, a new scoring system for pathological evaluation was created. The results obtained by this scoring system suggest that immunohistochemical markers Ki-67 (MIB-1), bcl-2, p53 together with the AgNOR staining could be useful, by the scoring system, as an adjunct to the current accepted morphologic criteria in differentiating smooth muscle tumors of the uterus.