Assessment Of Proliferative Activity Research Articles

Counting mitoses: SI(ze) matters

The assessment of proliferative activity by counting mitoses is something that most if not all histopathologists practice, as it is required for diagnosis and/or grading of many tumours. In the past, mitoses were often counted ‘per high power field’, which was convenient, but was regarded as scientifically questionable even 40 years ago, as it ignored the fact that microscope fields may differ substantially, even at the same high power (×400) magnification.1 Other features such as vessels, cell numbers or apoptoses are also counted in some circumstances, and the same issues apply.

Extragingival peripheral ameloblastoma arising in the infratemporal fossa: A case report with an assessment of proliferative activity

AbstractBackgroundPeripheral ameloblastoma is an extraosseous variant of ameloblastoma. We report a rare case arising in an extragingival location.Case PresentationThe patient was a 79‐year‐old man with a firm nodule in the right‐side buccal mucosa. Imaging examinations showed a well‐demarcated mass in the right masticator space (infratemporal fossa). The diagnosis of ameloblastoma was made from the biopsy specimen. After conservative tumor excision, the patient had no recurrence during the follow‐up period of eight and a half years. The Ki‐67 labeling index indicated the nonaggressive nature of the tumor.ConclusionConservative surgery is applicable to extragingival peripheral ameloblastomas.

Invasive lobular carcinoma of the breast: assessment of proliferative activity using automated Ki-67 immunostaining

Invasive lobular carcinoma (ILC) is almost always classified as Nottingham histological grade 2. Despite this, prognosis is markedly varied, with some ILCs behaving more akin to grade 3 invasive ductal carcinoma (IDC). Methods to separate these aggressive ILCs are needed. Digital image analysis (DIA) of the Ki-67 biomarker has potential in this regard; thus, we sought to determine the feasibility of its use for automated evaluation of ILC. An initial pilot study demonstrated no ILC specific changes were required to our Ki-67 DIA algorithm for reproducible results. Subsequently, 42 consecutive cases of ILC were evaluated by visual mitosis counting in H&E stained sections and by DIA on Ki-67 stained sections. Ki-67 proliferative index (PI) DIA showed significant correlation with visual mitosis counting on H&E stained sections (rs=0.63; p<0.05), significant strong correlation (rs=0.78; p<0.05) and substantial agreement (κ=0.62) with manual/visual Ki-67 assessment and significant positive associations with grade, nodal status and 'pleomorphic' ILC subtype, and a wide stratification of values in classical/grade 2 ILC. In conclusion, DIA of Ki-67 PI in ILC is feasible, correlates with mitotic index, manual/visual Ki-67 PI and clinico-pathological variables. The broad stratification of Ki-67 PI in classical/grade 2 ILC supports its practicability as a biomarker with prognostic and predictive potential, although large studies with outcome data are required for validation.

A standardised diagnostic approach to pituitary neuroendocrine tumours (PitNETs): a European Pituitary Pathology Group (EPPG) proposal

The 2017 World Health Organization (WHO) classification proposes to type and subtype primary adenohypophyseal tumours according to their cell lineages with the aim to establish more uniform tumour groups. The definition of atypical adenoma was removed in favour of high-risk adenoma, and the assessment of proliferative activity and invasion was recommended to diagnose aggressive tumours. Recently, the International Pituitary Pathology Club proposed to replace adenoma with the term of pituitary neuroendocrine tumour (PitNET) to better reflect the similarities between adenohypophyseal and neuroendocrine tumours of other organs. The European Pituitary Pathology Group (EPPG) endorses this terminology and develops practical recommendations for standardised reports of PitNETs that are addressed to histo- and neuropathologists. This brief report presents the results of EPPG's consensus for the reporting of PitNETs and proposes a diagnostic algorithm.

Correlation between TopIIα and ki-67 expression in tumors of luminal, primary operable breast cancer without HER2/neu overexpression in postmenopausal women as a prognostic factor.

e12065 Background: Assessment of proliferative activity is important in terms of tumor prognosis. Topoisomerase IIα (TopIIα) and ki-67 are common markers of breast cancer (BC) cell proliferation. The purpose of the study was to assess the correlation between TopIIα and ki-67 expression as a prognostic factor in luminal, primary operable breast cancer without Her 2 neu overexpression in postmenopausal women. Methods: 60 postmenopausal patients with BC (invasive ductal carcinoma) were equally divided into 3 groups: I –luminal A BC, surgical treatment with subsequent radiotherapy and hormonal therapy; II – luminal B BC, surgical treatment with subsequent radiotherapy and hormonal therapy; III – luminal B BC, surgical treatment with subsequent radiotherapy, polychemotherapy and hormonal therapy. Mean age of patients: I – 76.16±3.14 years, II – 65.0±3.91, III – 74.0±2.54 years. Immunohistochemical study was performed with mouse monoclonal ki-67 (Thermo scientific) and TopIIα (Santa Cruz Biotechnology) antibodies using the Reveal Polyvalent HRP-DAB Detection System. Results were analyzed using the STATISTICA 10.0 program (StatSoftInc., USA). Results: The average expression levels of the ki-67 marker in the groups were: I - 12.3±1.4%, II - 15.1±3.1%, III - 37.0±7.1%; TopIIα expression – 3.5±1.6%, 16.0±5.9%, 21.7±6.4%, respectively. The statistically significant Spearman correlation between TopIIα and ki-67 was observed both as general in groups (r = 0.787 at p &lt; 0.001) and in groups with luminal B subtype (groups II and III). Strong positive correlation between TopIIα and ki-67 was registered in groups II (r = 0.941 at p &lt; 0.01) and III (r = 0.864 at p &lt; 0.001) with luminal B subtype. Weak correlation was observed in group I with luminal A subtype (r = 0.477 at p≥0.05). Conclusions: The study revealed a correlative increase in the level of TopIIα with simultaneous overexpression of the ki-67 protein in the studied groups. This indicator can be considered predictive for breast cancer.

Immunocytochemical study of canine lymphomas and its correlation with exposure to tobacco smoke.

Aim:Canine lymphoma is one of the most common canine neoplasms, but little is known regarding the effects of exposure to tobacco smoke on their biologic behavior. As cytology is the most frequent diagnostic method of canine lymphoma, the aims of this study were to perform an immunocytochemical study of canine lymphomas, including subtyping and cell proliferation analysis, and to establish their correlation with tobacco smoke exposure.Materials and Methods:A total of 23 dogs diagnosed with lymphoma were subjected to careful fine-needle biopsies of enlarged lymph nodes. The smears were air-dried, fixed with cold acetone, and immunocytochemically stained using CD3, PAX5, and Ki-67. Owners were requested to complete an epidemiologic questionnaire.Results:According to the updated Kiel classification, 65% were B-cell lymphomas - three low grade (LG) and 12 high grade (HG) and 35% were T-cell -two LG and six HG. Thirteen tumors presented high Ki67 indexes (>40%) (11 HG and 2 LG), two revealed moderate ones (20-40%) (1 HG and 1 LG), and three had low indexes (≤20%) (1 HG and 2 LG). Both a significant positive correlation and a significant linear-by-linear association (p=0.018) were observed between high Ki67 indexes and smoking owners (r=0.753, p=0.002) as well as with the number of smokers in the household (r=0.641, p=0.001). Moreover, the mean percentage of Ki67+ cells from the group of “smoker owners” was statically higher (p=0.011) than that from the “non-smoker owners.”Conclusion:The results suggest that cytological diagnosis of canine lymphomas benefits from being complemented with immunocytochemical studies that include subtyping and assessment of proliferative activity, both contributing for the prognosis and therapeutic planning. Furthermore, exposure to tobacco smoke seems to be related to the biological behavior of canine lymphomas.

Significance of immunohistochemistry method for diagnosing of stomach tumors

The article is dedicated to the diagnosis of malignant tumors of the stomach, analyzing divergences of diagnoses after routine morphological researches and immunomorphological methods with monoclonal antibodies using, assessment of proliferative activity of different groups of tumors of this localization. Our investigation demonstrated that in the group of gastric tumors mistaken primary diagnoses were identified in 33 of 62 cases (53.2%). Proliferative score estimation is too important to determine the potential for malignancy of gastrointestinal stromal tumors and the degree of differentiation of neuroendocrine cancers.

16. Assessment of ki67 proliferative activity in breast carcinoma: a comparison of rapid manual assessment with computerised image analysis

Background There has been increasing interest in recent years in molecular assessment of proliferative activity (PA) as a means of stratifying prognosis in some subsets of invasive breast carcinoma. In addition to commercial molecular risk stratification tools, which are strongly influenced by proliferative markers, recent consensus guidelines have suggested incorporation of Ki67 assessment of PA by immunohistochemistry into treatment selection decisions in some circumstances. Despite this, there are significant practical obstacles to measurement of PA outside a research setting. In particular, recommended manual methods involve counting a minimum of 1000 cells, which is likely to be too time consuming for ready incorporation into a busy clinical workload. Aims and Methods We conducted a prospective study of 70 cases in routine practice to compare two less time consuming methods of Ki67 assessment: a rapid semi-quantitative manual method and computerised image analysis. The latter has previously been shown to be strongly correlated with formal manual assessment. We also sought to determine whether dual staining with cytokera-tin and Ki67 was necessary to exclude background cells from automated proliferation assessment. Results We found that rapid semi-quantitative manual assessment showed only a fair correlation with automated counting (correlation coefficient 0.7). There was a strong correlation between single stained and dual stained specimens by automated assessment (correlation coefficient 0.9). Conclusions Our results suggest that computerised image analysis may be the best alternative to formal manual Ki67 counting when that method is impractical in busy clinical practice.

Comparison of Methods for Proliferative Index Analysis for Grading Pancreatic Well-Differentiated Neuroendocrine Tumors

Assessment of proliferative activity is required for grading well-differentiated pancreatic neuroendocrine tumors. However, a standardized method for obtaining the Ki-67 proliferative index is lacking. This study compared proliferative activity obtained by 3 methods: single-field hot spot (Ki-67 HS) and 10 consecutive field average (Ki-67 CFA) using the Ventana image analysis system (Ventana Medical Systems, Tucson, AZ) and mitotic index (MI). These methods resulted in discrepant grades in 30 (67%) of our 45 cases. With the current Ki-67 cutoff of more than 2% for intermediate-grade tumors, MI, CFA, and HS resulted in specificities of 91%, 94%, and 31%, respectively, for detecting metastasis, with positive predictive values (PPVs) of 25%, 67%, and 31%, respectively. At a higher Ki-67 cutoff of 7.5%, HS analysis resulted in a specificity of 94% and PPV of 71% for predicting metastasis. While single-field HS analysis may be practical and reliable at a higher cutoff, this study emphasizes the variability that can exist when different methods of assessment are used.

Assessment of Proliferative Activity by AgNOR and PCNA in Prostatic Tissues of Ram Lambs Implanted with Zeranol

The aim of this study was to assess cellular proliferation using silver-stained nucleolar organizer regions (AgNOR) and the proliferating cell nuclear antigen (PCNA) in various tissues in the prostate of ram lambs implanted with increasing zeranol doses and to compare the sensitivity of different tissues of lamb prostate to zeranol. Twenty-four Akkaraman lambs were implanted with increasing zeranol doses, including 12 mg (n = 8), 24 mg (n = 8) and 96 mg (n = 8), with eight lambs serving as controls. After 33 days, the prostate tissues of the lambs were stained using AgNOR and PCNA techniques. The prostate tissues were divided into two compartments--the epithelial tissues, including glandular acinus, collecting duct and penile urethra, and the non-epithelial tissues, including interstitial tissue and striated muscle. AgNOR dots and PCNA index on each prostatic tissue were counted under a light microscope and were evaluated statistically. AgNOR staining in the treatment groups showed a higher score in the non-epithelial tissues than the epithelial components, whereas the PCNA index was significant in the epithelial tissues and non-epithelial tissues had very low PCNA immunostaining. According to the PCNA index, collecting duct epithelium showed more sensitivity to increasing zeranol doses and according to AgNOR counts, there was no difference of sensitivity to zeranol among tissues of the same origin. Both AgNOR counts and PCNA indexes seem to be valuable proliferating markers for the epithelial components of ram prostate, but PCNA index had no significance in relation to the non-epithelial components in contrast to AgNOR counts. Therefore, the controversial results arising from the combined use of both techniques as proliferating markers for the ram prostate should be considered in further studies.

Assessment of Proliferative Activity and Angiogenesis in Ameloblastoma : A Comparison Based on Patient Age

Background. Plexiform ameloblastoma is more common in younger patients while and the follicular pattern is more frequently seen in older patients. However, factors implicated in determining the microscopic growth pattern of ameloblastoma are unclear.Methods. A total of 23 cases of ameloblastoma were included in this study and were divided into 2 groups according to age : group A≤15 years (12 cases), and group B≥60 years (11 cases). Each group was assessed for predominant histological pattern (follicular vs. plexiform) and for immunoreactivity with 2 monoclonal antibodies : Ki-67 and CD31. Ki-67 labeling index, intratumor microvessel density (IMVD) and intratumor microvessel area (IMVA) were calculated in each case.Results. The majority of cases in group A exhibited a plexiform pattern, while the follicular pattern predominated among group B. Ki-67 labeling index, IMVD, and IMVA were significantly higher in group A than in group B. When the 2 histological patterns of ameloblastoma were compared, only IMVD and IMVA were statistically higher in plexiform ameloblastoma.Conclusions. Our results suggest that angiogenesis could affect the pattern of tumor growth in ameloblastoma. Both angiogenesis and growth pattern were influenced by patient age.

Flow cytometry and quantitative immunohistochemical study of cell cycle regulation proteins in invasive breast carcinoma: prognostic significance.

Between January 11, 1991 and January 8, 1992, 104 patients with previously untreated, invasive, primitive breast carcinoma were admitted to the authors' hospital. For each patient, flow cytometry DNA analyses on frozen samples and on immunohistochemical staining were performed, including Ki-67, cyclin A, p53, and p21(waf1) (p21), with assessment of the percentages of positive nuclei were assessed. Correlations with classic clinicopathologic data and survival (overall, metastasis free, or recurrence free) and a multivariate analysis were performed. After a multivariate analysis according to a Cox model that was stratified by age, tumor size, tumor grade, lymph node status, and receptor status, among the factors studied, the presence of p21 was the unique remaining prognostic factor for patients with invasive breast carcinoma. Because of the lack of a correlation between p21 and proliferative factors (Ki-67, S-phase, and cyclin A), the authors combined p21 with those markers and found that, for the different combinations, after statistical analysis, only p21 combined with S-phase or with cyclin A and lymph node status were salient survival prognostic factors. Immunohistochemical study of proteins involved in the cell cycle and assessment of proliferative activity using flow cytometric DNA analysis aided the authors in singling out correlations of cyclin A and S-phase, along with p21, with metastasis free survival and overall survival in patients with invasive breast carcinoma. These promising results will require confirmation in a larger series of patients.

The correlation among different immunostaining evaluation methods for the assessment of proliferative activity in uveal melanoma

Purpose. Proliferative index of uveal melanoma cells serves as a prognostic factor. However, different methods are being used to determine proliferative index using immunostaining for proliferative markers. The major differences among assessment methods are whether the mean proliferative activity of all tumor cells in a section or for areas of rapidly proliferating cells is determined, and whether 10 or 20 fields are being evaluated. We aimed to assess the correlation among proliferative indexes obtained by different immunostaining evaluation methods. Methods. Sections from 60 formalin-fixed paraffin-embedded uveal melanomas were immunostained with MIB-1 antibody. Immunostaining was assessed by counting immunoreactive cells in semi-randomly selected fields (nonselective method) and in areas with maximal immunoreactivity (selective method). Proliferative activity indexes according to the two methods in 10 and 20 high power fields (one high power filed = 0.785mm²) were calculated and compared. Results. The mean positive cell counts per mm² (MPCC/mm²) according to the selective and the non-selective methods were 29.8 ± 8.1 and 10.7 ± 2.4 respectively (p = 0.004, paired t-test). Despite these different values, there was a good correlation between the MPCC/mm² obtained by the nonselective and the selective methods for each tumor (r = 0.737, p < 0.0001, Pearson correlation). In addition, according to both methods, the readings of the first 10 fields and those of fields 1-20 correlated well. Conclusions. Mean proliferative activity of uveal melanoma cells correlates with the proliferative activity in localized areas of the tumor with rapidly proliferating cells. Therefore, uveal melanomas are classified similarly by the selective and non-selective methods of immunostaining evaluation. However, the two methods yield different proliferative index values for the same tumors, a fact that should be taken into account when comparing results of studies in which different techniques were used for immunostaining evaluation.

Assessment of Proliferative Activity in Colorectal Carcinomas by Quantitative Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR)

The monoclonal antibody Ki-67 and the isospecific monoclonal antibody MIB-1 are routinely used in oncology to assess the proliferation index of tumor cells. A more objective and sensitive method is the determination of the of Ki-67 protein-specific mRNA by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). In 25 resected colorectal adenocarcinomas of different stages and grades we determined between 0.2 and 4.4 amol (10−18 mol) Ki-67 protein-specific mRNA per microgram total RNA (median = 0.88 amol). The corresponding Ki-67 indices (expressing the percentage of Ki-67/MIB-1 positive tumor cells) ranged from 41 to 81% (median = 61%). We found a good correlation between Ki-67 index and mRNA expression (r = 0.75), a significant correlation between both data and tumor stage (primary tumor, regional nodes, metastasis [pTNM] staging classification) (p < 0.001), but not between both data and tumor grade. Both Ki-67 indices (p = 0.05) and mRNA levels (p = 0.014) correlated significantly to the patients' survival. These results demonstrate that the Ki-67 protein-specific quantitative RT-PCR is a useful method for the characterization of tumor cell proliferation.

Prognostic Relevance of a Histological Grading System Using MIB-1 for Adult Soft-Tissue Sarcoma

Several histological grading systems have been proposed and found as strong indicators of outcome in soft-tissue sarcomas. However, a putative independent prognostic influence of recently developed biological and molecular markers remains to be established. This study investigated the prognostic relevance of a histological grading system based on the assessment of proliferative activity in adult soft-tissue sarcomas of the extremities, trunk, head, and neck. Tissue blocks from 95 of 108 patients without distant metastases or regional lymph node involvement were available. Immunohistochemical staining for MIB-1 and p53 was done on paraffin-embedded sections. All clinicopathologic and immunohistochemical variables and patient survival were assessed using univariate and multivariate analyses. Variables included histological grading based on the modified Fédération Nationale des Centres de Lutte Contre le Cancer (FNCLCC) system using the MIB-1 score for the estimation of the proliferative potential of the tumors. Variables associated with overall survival were tumor site in the trunk, head and neck, mitosis count, necrosis, MIB-1 score, FNCLCC grade, modified FNCLCC grade using the MIB-1 score, and stage (all p values <0.05). In multivariate analysis, the modified grade proved to be the most significant predictor of shortened overall survival, in addition to tumor site in the trunk, head, and neck. Overexpression of p53 did not correlate with increased risk of tumor mortality. Using MIB-1 to replace mitosis counts in the FNCLCC system improves grading of soft-tissue sarcomas, and this in conjunction with other important factors appear to be more accurate prognostic factors for survival, and for patient selection in investigational adjuvant treatment trials.

Assessment of proliferative activity in breast cancer: MIB-1 immunohistochemistry versus mitotic figure count

The proliferative activity is one of the most important single prognostic parameters in breast cancer diagnosis and the time-honored measure of proliferative activity, the mitotic figure count, is an integral component of most combined prognostic scores. The detection of the cell cycle-specific antigens Ki-67, and the development of anti-Ki-67 antibodies, including the paraffin-reactive antibody MIB-1, have established immunohistochemical detection of cell cycle-specific antigens as a measure of proliferative activity in breast cancer diagnosis. The current study was performed to correlate mitotic figure counts with the proliferative activity as assessed by MIB-1 immunohistochemistry, taking into consideration the interobserver reliability of 5 pathologists in estimating mitotic figure counts. In 32 consecutive invasive ductal breast carcinomas, mitotic figure counts were performed independently by 5 pathologists. Mitotic activity was expressed as number of mitotic figures per 10 high-power fields and in a 3-tier score according to the Scarff Bloom Richardson system. Immunohistochemistry was performed using MIB-1 antibody, heat-induced epitope retrieval, and the standard avidin-biotin-immunoperoxidase method. MIB-1 immunohistochemistry was assessed in 3 representative 20 × fields by semiquantitative estimation (% of tumor cells positive) and by image analysis (number of MIB-1-positive cells/mm 2). We found a high degree of interobserver correlation among 4 experienced pathologists, in both mitotic figures per 10 high-power fields and the 3-tier scoring system. We observed significant, albeit weak, correlations between semiquantitative and quantitative MIB-1 immunohistochemistry and the number of mitotic figures per 10 high-power fields ( r between .36 and .53), but this significance was lost in 3 of the 5 observers when mitotic activity was expressed in the 3-tier scoring system. This study confirms mitotic figure counting in the hands of experienced pathologists as a valid, reproducible means of assessing proliferative activity in routine breast cancer diagnosis. The statistically significant, albeit only weak, correlation with MIB-1 immunohistochemistry is in agreement with results obtained by others and suggests that MIB-1 immunohistochemistry cannot be translated by a simple conversion factor into combined prognostic scores to replace the time-honored mitotic figure counts.

Proliferative activity as measured by MIB-1 labeling index and long-term outcome of visual pathway astrocytomas in children.

Although most visual pathway tumors are low-grade gliomas their biologic behavior is highly unpredictable. In order to determine whether assessment of proliferative activity can assist in predicting tumor behavior, we studied the MIB-1 labeling indices (MIB-1 LIs) in surgical specimens and monitored tumor growth in 31 consecutive children operated on between 1978 and 1997. The MIB-1 LIs at diagnosis varied from 0-10.6% (mean +/- SD, 3.27 +/- 2.49%). Tumor progression occurred in 19 patients leading to death in seven, three of whom had neurofibromatosis type 1 (NF1). No association between MIB-1 LI at initial diagnosis and both progression free and overall survival was apparent. However, the MIB-1 LIs increased to 15.2% and 18% in two patients with NF1 who developed highly malignant gliomas 6 and 6.5 years after irradiation. In the remaining patients the MIB-1 LIs did not change significantly over time in a total of 17 repeat surgeries. Three patients with LIs of 6.8%, 10.6% and 8.8% are stable after 6, 4.5 and 3.5 years with partial resection, biopsy and subtotal resection, respectively, and no further therapy in the first two and chemotherapy in the latter. Three patients (10%) with LIs of 6.4%, 4.8% and 2.2% either presented with or developed leptomeningeal spread during follow-up. While MIB-1 LI does not appear to assist in clinical decision making patient numbers were too small to find out whether response to chemotherapy varies with proliferative potential.

Assessment of Proliferative Activity Using the MIB1 Antibody Helps to Distinguish Polymorphous Low Grade Adenocarcinoma from Adenoid Cystic Carcinoma of Salivary Glands

Salivary polymorphous low grade adenocarcinoma (PLGA) and adenoid cystic carcinoma (AdCC) bear a superficial histological and immunophenotypic resemblance to each other, but can usually be separated by conventional microscopic examination. However, this is not always so, such as with PLGAs displaying plentiful cribriform structures, and when only limited tissue from small biopsies is available for study. Twenty-one cases of PLGA and 20 cases of AdCC from the surgical pathology files in Plzen, Exeter and Helsinki were incubated with the MIB1 antibody using the supersensitive avidin-biotin peroxidase technique after microwave pretreatment. The antibody recognizes the cell cycle associated antigen Ki-67 on routinely processed formalin-fixed paraffin-embedded tissues. The percentage of positively stained tumor cell nuclei constituted the MIB1 index. It was found that the PLGAs had a mean MIB1 index of 2.4% (range 0.2-6.4), while the AdCCs had a mean value of 21.4% (range 11.3-56.7). Within the PLGA group, the 12 tumors which did not form micropapillae had a somewhat lower mean MIB1 index (1.4%) than those nine in which such structures constituted a significant but minor component (3.4%). These results indicate that the MIB1 index was significantly higher in the AdCCs than the PLGAs and that the figures showed no overlap zone. We conclude, therefore, that immunohistochemical staining with the MIB1 antibody appears to be a potentially useful supplementary diagnostic tool in differentiating difficult cases of PLGA from AdCC.

Nuclear morphometry, immunohistochemical staining with Ki-67 antibody and mitotic index in the assessment of proliferative activity and prognosis of primary malignant melanomas of the skin.

Nuclear morphometry, immunohistochemical staining with Ki-67 antibody and mitotic index were studied in primary cutaneous malignant melanomas. The number of Ki-67 positive cells/ 200 tumor cells did not correlate with any nuclear morphometrical parameters, and it only approached but did not reach significant correlation with melanoma thickness according to Breslow. The nuclear area, short axis and long axis correlated with melanoma thickness, but the nuclear axis ratio (which reflects the sphericity of nuclei) and melanoma thickness did not show significant correlation. Mitotic index was higher in thick melanomas and in melanomas with high Ki-67 positivity, large nuclear area, long nuclear short axis, and small nuclear axis ratio. In Cox's stepwise proportional hazard model, melanoma thickness and the nuclear axis ratio were significant independent prognostic factors for patient survival, while the nuclear area, short axis and long axis, gender, age, Clark level, mitotic index and Ki-67 positivity lacked significant independent prognostic value. The results suggest that the proliferative activity of tumor cells does not alone explain the great importance of tumor thickness as prognosticator in melanoma. The thickness of melanoma measured according to Breslow and the nuclear axis ratio are more efficient prognosticators in melanoma than parameters associated with proliferation.

Proliferation Markers and Their Uses in the Study of Endocrine Tumors.

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