Mitotic indices, anti-PCNA immunostaining, and AgNORs in thick cutaneous melanomas displaying paradoxical behaviour

Proliferating Cell Nuclear Antigen Immunoreaction in Adrenal Tumors

Aims and background

We studied, retrospectively, 33 cases of adrenal tumors of children at the Pediatric Endocrinology Unit, Children's Institute, São Paulo State University Medical School, from 1975 to 1993. All patients had at least 2 years of follow-up with a few exceptions.

Methods

Clinical follow-up data were correlated with histopathologic review, laboratory data and cell kinetic evaluation (based on detection of proliferating cell nuclear antigens).

Results

With one exception, all the patients had presented signs of androgen production and had high levels of dehydro-epiandrosterone-sulfate. Tumor weight evaluation represented a good parameter of neoplasm evolution: of 19 cases weighing less than 250 g, 17 had no evidence of disease after surgery, and 2 had an unfavorable prognosis. Of 14 cases weighing more than 250 g, only 1 had no evidence of disease and 13 had an unfavorable evolution.

Conclusions

Proliferating cell nuclear antigen (PCNA) was not helpful to evaluate adrenal neoplasm evolution: our study did not show any correlation between PCNA score and prognosis.

Human mesenchymal stem cells enhance the systemic effects of radiotherapy

The outcome of radiotherapy treatment might be further improved by a better understanding of individual variations in tumor radiosensitivity and normal tissue reactions, including the bystander effect. For many tumors, however, a definitive cure cannot be achieved, despite the availablity of more and more effective cancer treatments. Therefore, any improvement in the efficacy of radiotherapy will undoubtedly benefit a significant number of patients. Many experimental studies measure a bystander component of tumor cell death after radiotherapy, which highlights the importance of confirming these observations in a preclinical situation. Mesenchymal stem cells (MSCs) have been investigated for use in the treatment of cancers as they are able to both preferentially home onto tumors and become incorporated into their stroma. This process increases after radiation therapy. In our study we show that in vitro MSCs, when activated with a low dose of radiation, are a source of anti-tumor cytokines that decrease the proliferative activity of tumor cells, producing a potent cytotoxic synergistic effect on tumor cells. In vivo administration of unirradiated mesenchymal cells together with radiation leads to an increased efficacy of radiotherapy, thus leading to an enhancement of short and long range bystander effects on primary-irradiated tumors and distant-non-irradiated tumors. Our experiments indicate an increased cell loss rate and the decrease in the tumor cell proliferation activity as the major mechanisms underlying the delayed tumor growth and are a strong indicator of the synergistic effect between RT and MSC when they are applied together for tumor treatment in this model.

Synchronous Comparative Evaluation of Fibronectin Continuity and Cellular Growth Kinetics in Malignant Cutaneous Melanoma

Cellular fibronectin mediates the adhesion of cells with the extracellular matrix and thus probably regulates tumor invasion. Evaluation of proliferating cell nuclear antigen expression and counting of silver nuclear organizer regions potentially assess proliferative fraction and biologic aggressiveness in several malignancies. We investigated the above markers’ prognostic value in 60 malignant melanomas of the skin. Deep Clark levels were statistically associated with discontinuous fibronectin staining pattern (SPII) ( P < .05) as well as with high proliferating cell nuclear antigen and silver nuclear organizer regions indexes ( P < .01 and P < .05, respectively). Fibronectin staining pattern (SPII) was frequently observed in thick melanomas ( P < .05). High proliferating cell nuclear antigen immunoreactivity positively correlated with mitotic activity ( P < .05), the presence of vertical growth phase ( P < .05), and increased silver nuclear organizer regions counts ( P < .05). Patients with continuous fibronectin staining pattern (SPI) and low proliferating cell nuclear antigen scores were unlikely to develop metastatic disease ( P < .01). Therefore, the simultaneous comparative assessment of these factors is very promising in predicting melanomas clinical evolution.

Silver-stained nucleolar organizer regions and immunoglobulins in cutaneous squamocellular tumors

This study was conducted to elucidate the biological activity of epidermal cells in cutaneous squamocellular tumors by counting the number of silver-stained nucleolar organizer regions (AgNORs), to estimate the quantity of Ig-producing cells and the inflammatory cellular infiltrate (ICI), and to achieve a comparative evaluation. Twenty cases of actinic keratosis (AK), 20 in situ squamous cell carcinomas (ISC), and 20 invasive squamous cell carcinomas (SCCs) were assessed using a silver colloid technique. Ig-producing or binding cells and ICI were also investigated immunohistochemically. In all samples, AgNORs, Ig-producing cells, and ICI increased in proportion to the degree of malignancy. With regard to AgNORs values, a statistically significant difference was confirmed between AK and ISC (p<0.01), AK and SCC (p<0.001), and ISC and SCC (p<0.05). IgG-producing cells predominated in each case. Furthermore, a linear correlation was detected between ICI and AgNORs in AK and ISC. The significant difference in the number of AgNORs among the 3 stages of involution of SCC reinforces the value of AgNORs as a marker for malignant potential. Despite the absence of a correlation between AgNORs and the proportion of Ig-producing cells, the association between ICI and AgNORs in AK and ISC was obvious.

Silver-stained organizer regions and immunoglobulins in cutaneous keratoacanthomas and squamous cell carcinomas

The aim of this study was to investigate the biologic activity of epidermal cells in keratoacanthomas (KAs) and squamous cell carcinomas (SCCs) by counting the number of silver-stained nucleolar organizer regions (AgNORs), to estimate the quantity of Ig-producing cells and the inflammatory cellular infiltrate (ICI), and to make a comparative evaluation. Thirty KAs (10 at growth stage, 10 at mature stage, and 10 at involution stage) and 28 SCCs (nine well differentiated-Grade 1 (G1), seven moderately differentiated-Grade 2 (G2), five poorly differentiated-Grade 3 (G3), and seven pseudoadenoid) were investigated. The KAs examined had a mean number of 1.727 AgNORs (S.D. 0.232), and IgG predominated in most cases. IgG and IgE increase at the involution, IgA remains at almost the same level, and IgM decreases during the maturity stage. The SCCs examined had a mean number of 2.105 AgNORs (S.D. 0.446). IgG predominated and gradually increased in proportion to the degree of malignancy. There is a significant difference in the number of AgNORs and the proportion of Ig subclasses in contrast to the cellular infiltrate among the three stages of KA. In SCCs, the number of AgNORs and the percentage of Igs and ICI increased gradually in proportion to the degree of malignancy.

Significance of cell kinetic parameters in the prognosis of malignant melanoma: a review

Malignant melanoma has been extensively studied concerning methods of predicting progression and clinical outcome. The maximum tumor thickness as measured by Breslow's method is the cornerstone prognostic criterion, but despite this, evolution of the disease in some patients remains unpredictable, confirming that new reliable prognostic factors are awaited. Cell kinetic evaluation has been shown to be a useful tool for assessing the prognosis of breast and gastrointestinal cancer patients. Indeed, in these fields, the mitotic index and MIB-1 expression index, which are indirect estimates of the growth fraction of tumor cell population, are commonly shown to correlate with tumor grade and patient survival and presented as prognostic factors. In melanoma, results of cell kinetic investigations are conflicting: some studies have established a link between high proliferative activity and a bad prognosis, whereas other reports suggest the opposite. The aim of this review is to discuss these findings.

Ontogeny of rat chondrocyte proliferation: studies in embryo, adult and osteoarthritic (OA) cartilage

The aim of this work was to study the ontogeny of chondrocyte cell division using embryo, adult and osteoarthritic (OA) cartilage. We searched for mitosis phases and performed a comparative evaluation of mitotic index, basic fibroblast growth factor b (FGFb), transforming growth factor beta1 (TGF-beta1) receptors, cyclin dependent kinase (CDK1) and Cyclin-B expression in fetal, neonate, 3, 5, 8 weeks old rats and experimental OA. Our results showed that mitosis phases were observed in all normal cartilage studied, although, we found a decrease in mitotic index in relation to tissue development. No mitosis was detected in OA cartilage. We also found a statistical significant reduction in cell number in OA cartilage, compared with the normal tissue. Furthermore, FGFb and TGF-beta1 receptors diminished in relation to tissue development, and were very scarce in experimental OA. Western blot assays showed CDK-1 expression in all cases, including human-OA cartilage. Similar results were observed for Cyclin-B, except for 8 weeks, when it was not expressed. Our results suggest that cell division seems to be scarce, if not absent within the OA cartilage studied. Nevertheless, the existence of factors essential for cell division leaves open the question concerning chondrocyte proliferation in OA cartilage, which is likely to be present in the early stages of the disease.

Proliferative activity in oral salivary gland tumors: the role of PCNA and AgNOR assessed by a double staining technique

The aim of this study was to evaluate the role of PCNA and AgNOR in the assessment of salivary gland tumor proliferation using a double staining technique. Ten cases of pleomorphic adenoma (PA) and seventeen cases of adenoid cystic carcinoma (ACC) were examined. Numeric and morphometric parameters of AgNOR were evaluated and compared in PCNA-positive and PCNA-negative nuclei. There were statistically significant differences in AgNOR numbers, perimeters and contour indices between PCNA-positive and -negative nuclei in the PA samples. The ACC samples demonstrated significant differences only in the AgNOR areas. Our results show that in salivary gland tumors there is not always a relationship between proliferative activity evaluated by AgNOR numeric and morphometric parameters and PCNA immunostaining.

Cytomorphological variations, proliferation and angiogenesis in the prognosis of cutaneous melanoma

Depth of invasion and stage of the disease are well known prognostic indicators in cutaneous melanoma (CM). However, the role of other parameters, such as the variations in cytomorphology of melanocyte tumours, mitotic activity and angiogenesis is still open to question. The aim of this study was to analyse proliferation by mitotic activity index (MAI) and immunostaining of proliferating cell nuclear antigen (PCNA), and the intensity of neovascularization (microvessel density; MVD) in CM clinical stage I in relation to epithelioid, spindle and nevoid cell type, histological type (superficial spreading melanoma and nodular melanoma), Clark's level and Breslow thickness. Finally, the role of all parameters in the prognosis of CM was evaluated. Statistical analysis demonstrated that cytological characteristics of CM correlate only with Clark's level, while histological types correlate with MAI, PCNA and MVD. MAI and PCNA also showed correlation between groups according to Clark's level and Breslow thickness. Finally, tumour cell PCNA was found to correlate with MVD. Survival of patients with CM correlated significantly with MAI. These results suggest that cytological variation, histological type, PCNA and MVD alone are not independent prognostic parameters, whereas MAI is a potentially important prognostic marker in CM.

MIB-1 immunoreactivity correlates with biologic behaviour in canine cutaneous melanoma

The growth fraction of 68 canine cutaneous melanomas was determined by immunostaining with MIB-1, a monoclonal antibody to a Ki-67 epitope that recognizes all proliferating cells. Fifty tumours were classified histologically as benign and 18 as malignant. The Ki-67 proliferative index (percentage of positive cells over 500 neoplastic cells) was low (< 15%) in 55 cases and high (> or = 15%) in 13 cases. High Ki-67 proliferative index and histological malignancy were both associated with significantly poorer 2-year survival (P < 0.0001). However, the predictive value of the Ki-67 proliferative index (97%) was higher than the predictive value of classical histology (91%). The evaluation of the growth fraction by the Ki-67 proliferative index is highly predictive of the biological behaviour of canine cutaneous melanoma.

Prognostic value of Ki-67 expression in localized cutaneous malignant melanoma

BACKGROUND

The proliferative activity of some tumors is related to the development of metastatic disease and survival. Thus it could be used as a potential prognostic variable.

OBJECTIVE

The purpose of this study was to determine the prognostic value of the Ki-67 index and of a "proliferation-based prognostic index" (PBPI, derived as tumor thickness x Ki-67 index/100) in localized cutaneous malignant melanoma (CMM).

METHODS

The Ki-67 index (percent of total tumor nuclei) was determined in a series of 84 localized CMMs, with the use of the alkaline phosphatase-antialkaline phosphatase labeling method in formalin-fixed, paraffin-embedded material, and was correlated with other prognostic variables. Survival analysis was performed to determine whether the Ki-67 index and the PBPI could be predictive of metastatic spread or recurrent disease. A stratified analysis of these two parameters according to the tumor thickness was done.

RESULTS

An association among the Ki-67 index and location, Clark level, tumor thickness and stage, and prognostic index was detected. Increased Ki-67 index and PBPI were associated with poorer overall survival (P =.03 and P <.0001, respectively) and disease-free survival (P =.01 and P <.0001, respectively). However, after stratification for thickness, only the PBPI showed independent prognostic significance, restricted to tumors thicker than 4 mm (P =. 03).

CONCLUSION

The determination of the PBPI in CMM conveys prognostic information for localized thick (>4 mm) CMM, identifying two groups of patients with distinct outcome.

Silver-stained nucleolar organizer regions (AgNORs) as a prognostic value in malignant melanoma

The nucleolar organizer regions (NORs) are chromosomal loops of DNA and proteins involved in ribosomal synthesis. By silver staining, they can be identified as black dots (AgNORs) in the nuclei. Their size and number reflect cell and nuclear activity. Therefore, AgNOR count may correlate with the proliferative activity of tumors. In malignant melanoma, correlation between AgNOR count and the growth phase was found. However, the value of AgNORs in determining prognosis is disputable. Our purpose was to evaluate the role of AgNORs in predicting the biological behavior of melanoma. Paraffin-embedded sections of 30 cases of primary melanoma, 0.4-5 mm thick (mean, 1.6 mm) were stained with silver. Follow-up of all patients was at least 5 years. For each tumor, at least 50 cells were randomly selected for AgNOR count at a final magnification of 500, and the mean of AgNOR content was calculated. Sample parameters corresponded well to the epidemiology and the natural history of melanoma. AgNOR counts (0.78-4.26; mean, 1.42+/-0.72) correlated with tumor thickness (p = 0.01); thus, most superficial tumors had low AgNOR counts, whereas most deep tumors (> or = 1.5 mm) showed high counts. Patients who had tumors with AgNOR counts lower than the median had longer disease-free interval (DFI) than did patients who had tumors with higher counts (p = 0.02). Furthermore, in a multivariate Cox analysis, AgNOR count was independent of tumor thickness in determining DFI (p = 0.05). Therefore, AgNORs may serve as a parameter to predict more accurately the progression of melanomas (mainly thin ones). Larger studies are needed in order to consolidate these preliminary results and to characterize AgNOR value further as a prognostic factor in melanoma.

Mitotic rate and S-phase fraction as prognostic factors in stage I cutaneous malignant melanoma

Clinical data from 369 patients with clinical stage I cutaneous malignant melanoma treated in Kuopio University Hospital district between 1974 and 1989 with a mean follow-up of 6.4 years were analysed. Clinical parameters, histology, DNA index, S-phase fraction (SPF) and mitotic indices [mitotic activity index (MAI) and volume-corrected mitotic index (M/V index)] were correlated with the outcome of the disease to establish their value as predictors of stage I cutaneous malignant melanoma. In univariate survival analyses, bleeding, gender, tumour thickness, level of invasion according to Clark, TNM category, MAI, M/V index and SPF were the most significant predictors of recurrence-free (RFS) and overall survival. In Cox's multivariate analysis, tumour thickness (P = 0.0021), bleeding (P = 0.0106) and M/V index (P = 0.0058) predicted poor RFS in the 259 patients available for the analysis. Poor overall survival was predicted by MAI (P = 0.0002), bleeding (P = 0.004), SPF (P = 0.009) and male gender (P = 0.034). The present results indicate that mitotic activity index (MAI), volume-corrected mitotic index (M/V index) and S-phase fraction (SPF) are important prognostic factors in addition to the well-established Breslow thickness in stage I cutaneous malignant melanoma.

Prognostic significance of MIB-1 proliferative activity in thin melanomas and immunohistochemical analysis of MIB-1 proliferative activity in melanocytic tumors

Metastasis from thin melanomas is rare and unpredictable. In order to assess the prognostic value of the proliferation marker, MIB-1, immunohistochemical staining was evaluated in a retrospective case-control study of 11 thin melanomas with documented metastasis and 11 control tumors that failed to metastasize. Tumors selected were < 1-mm thick and were individually matched for tumor thickness, date of excision, and patient age and sex. Analysis of MIB-1 expression as both a mean and a maximum level for the case and control groups revealed no association with metastasis. Wilcoxon's matched-pairs signed-rank test had p-values of 0.45 for the maximum values and 0.79 for the mean values. For the 11 thin melanomas that metastasized, there was a weak, yet statistically insignificant, correlation between the proportion of cells positive for MIB-1 and the length of the relapse-free period [Spearman's correlation coefficient = 0.20 for the maximum level (p = 0.56) and 0.19 for the mean level (p = 0.58)]. These results suggest that MIB-1 expression may be of limited value as a prognostic marker for increased risk of metastasis in patients with thin melanomas. MIB-1 immunohistochemistry was also performed on 25 benign and 70 malignant paraffin-embedded melanocytic tumors to evaluate the level of MIB-1 expression at different stages of tumor progression. A progressive increase in MIB-1 expression was seen from benign tumors through to primary melanomas, with the highest level seen in metastatic melanomas. Within the group of primary melanomas, the MIB-1 score was shown to correlate significantly with tumor thickness and Clark's level of invasion (Spearman's correlation coefficient = 0.71 for level and 0.77 for thickness).

Studies on the proliferative activity of diethylnitrosamine-induced hepatocellular carcinomas in monkeys

In this study, synthetic phase fractions (SPFs) determined by flow cytometry and AgNOR counts were analysed in benign liver lesions (regenerative nodules and adenomas), hepatocellular carcinomas (HCCs), and lung metastases of a monkey hepatocarcinogenesis model to find out if AgNOR counts and SPFs can discriminate between malignant and non-malignant liver lesions. The average per cent SPF values and the AgNOR counts were significantly (P = 0.001) increased in regenerative liver nodules (5.30 per cent; 4.96), adenomas (5.34 per cent; 3.46) and well-differentiated HCCs (6.75 per cent; 4.47), compared with the untreated control livers (3.18 per cent; 0.98), but the differences between these three groups were not significant. In the poorly differentiated HCC group, however, the average SPF value (9.60 per cent) and AgNOR count (7.14) were significantly higher than in any of the other liver lesions examined. A significant correlation was found between the SPF values and AgNOR counts on the one hand, and differentiation and cytological grade of the HCC samples on the other. The results of this study show that the SPF values and AgNOR counts are not reliable in differentiating between regenerating liver nodules, adenomas, and experimental well-differentiated HCCs. The SPF value, however, may serve as a prognostic factor in HCC, since it was found to be significantly higher in HCCs with lung metastasis than in those without.

Immunohistochemistry: a prognostic as well as diagnostic tool?

The assessment of proliferating cell populations has been used to aid in the differentiation of benign from malignant neoplasms, and it has been hoped that assessment of proliferation markers and oncogenic determinants holds information regarding prognosis. Various markers, including Ki-67, p53 protein, bcl-2, and proliferating cell nuclear or paraffin-embedded tissue. These determinants may prove useful in understanding the biology of certain neoplasms and may carry prognostic information that influences clinical management. Results in this developing field must always be interpreted in the clinical and histological context. This article reviews the applicability of some commonly available markers to selected skin disorders.

Quantitation of proliferation-associated markers Ag-NOR and Ki-67 does not contribute to the prediction of lymph node metastases in squamous cell carcinoma of the vulva

A key prognostic parameter for vulvar carcinoma is the presence of lymph node metastases. Determination of proliferation markers has been suggested as a method to predict lymph node metastases in several tumor types. If this were true in vulvar carcinomas, reduced surgical therapy for patients with low-risk vulvar carcinoma could be considered. The authors analyzed whether the proliferation-associated markers silver nucleolar organizer region (Ag-NOR) and Ki-67 are predictors for inguinofemoral lymph node metastases in women with vulvar carcinoma. The authors also analyzed whether these proliferation markers are interrelated. Data were obtained from samples of 145 patients with T1/T2 squamous cell carcinoma of the vulva who were treated with vulvectomy and bilateral lymphadenectomy. None of these patients received preoperative therapy, and the invasion depth of the tumors was more than 1 mm. The median age was 71 years. The group consisted of 67 patients with differentiation grade 1, 64 with grade 2, and 18 with grade 3; 22% (15 of 67) of the patients with grade 1, 45% (29 of 64) with grade 2, and 43% (six of 14) with grade 3 had lymph node metastases. Formalin-fixed, paraffin-embedded sections were stained for proliferation markers Ag-NOR and MIB-1 (an equivalent of Ki-67 for fixed material). Both parameters were scored at the tumor stroma interface. Ag-NOR number and areas were quantified by interactive image analysis and Ki-67 index was scored microscopically with a grid. No relation was found between Ki-67 or Ag-NOR and lymph node metastases. A relation was found between Ki-67 and mitotic index (MI), but not between Ag-NOR and MI or Ki-67 index. Therefore, it is questionable whether Ag-NOR is, indeed, a marker for proliferation. The authors conclude that quantitation of Ki-67 and Ag-NOR does not contribute to the prediction of inguinofemoral lymph node metastases in squamous cell carcinoma of the vulva.

Increased nuclear volume in metastasizing "thick" melanomas

Tumor invasion is the most reliable prognostic factor for primary stage I melanoma. "Thick" melanomas, with a Breslow thickness of more than 4 mm, tend to have a poor prognosis. Exceptions occur: some patients have no further recurrence of tumor. In an attempt to determine prognostic markers for "thick" clinical stage I melanomas, we investigated the volume-weighted mean nuclear volume of primary melanomas with tumor invasions > or = 4.0 mm in 32 patients. Seventeen of these patients developed melanoma metastases within a follow-up period of 60 mo; 15 patients who did not developed metastases and were comparable with regard to clinical and histological criteria were selected as a comparison group. Volume-weighted mean nuclear volume (Vv) is determined by a technique that permits an unbiased, efficient, shape- and orientation-independent, 3-dimensional estimation of nuclear size in tissues. This technique has been employed successfully in the prognostic assessment of stage I and II melanomas and was recently proven to be a sensitive marker for thin, high-risk melanomas. In our patients, Vv was determined by computer-assisted image analysis on Feulgen-stained sections by stereologic estimation of the Vv. The mean Vv (+/-SD) of primary melanomas with subsequent metastatic course was 794.99 +/- 209.18 micron3 (range: 409.48-1161.9 micron3), whereas primary melanoma lesions without subsequent metastases exhibited a mean Vv 640.54 +/- 205.07 micron3 (range: 206.7-927.48 micron3). This difference was found to be statistically significant (p = 0.0439). "Thick" melanomas with subsequent metastases thus exhibited a significantly higher Vv than did melanomas that did not metastasize.

Proliferative activity in metastatic malignant melanoma: comparison of pre-treatment and post-treatment metastases

In this study, the proliferative activity of malignant melanoma metastases was assessed before and after isolated limb perfusion chemotherapy by quantitating AgNORs, mitoses and PCNA activity. No significant difference in either AgNOR count, mitotic activity or PCNA index was observed. We conclude that AgNOR count, mitotic activity and PCNA index were not significantly effected by isolated limb perfusion chemotherapy.

MIB-1 proliferative activity is a significant prognostic factor in primary thick cutaneous melanomas

Although the Breslow measurement of tumor thickness of melanoma is the most significant predictor of survival, the biologic behavior of thick lesions remains unpredictable. MIB-1, a monoclonal antibody to a Ki-67 epitope, recognizes all proliferating cells. Unlike Ki-67 antibody, which requires frozen tissue, MIB-1 can be used on formalin-fixed tissue. Proliferation, measured by MIB-1 expression and mitotic index, was assessed as a prognostic factor in a group of patients with clinical stage I thick cutaneous melanoma (tumor thickness 4 mm or greater), for which predicted survival is low. From a melanoma data base, 97 patients with this type of melanoma were identified. Of these, 64 had lesional tissue available for study. The median follow-up time was 3.8 years (range 0.42-13.6 years). The percentage of MIB-1 reactivity was scored as low at less than 10% (n = 33), intermediate at 10% to 20% (n = 17), and high at greater than 20% (n = 14). Melanomas with high MIB-1 reactivity were associated with significantly poorer cause-specific survival compared with tumors with intermediate (p < 0.0001) or low MIB-1 reactivity (p = 0.0025). Multivariate analysis demonstrated that MIB-1 reactivity was a significant independent prognostic factor related to cause-specific survival (p = 0.0002) and was more sensitive than tumor thickness or mitotic index in this select group of high-risk patients. Identification of individuals with stage I thick cutaneous melanoma who are at risk of recurrent disease may improve patient management as new therapeutic modalities become available.

Cell proliferation markers in predicting metastases in malignant melanoma

It is often difficult to predict the outcome of melanoma in patients with Clark level III-IV disease. We sought to identify markers of cell proliferation which may be useful in predicting prognosis. Patients with Clark's level III-IV malignant melanoma who had no local recurrences or metastases were matched with patients of comparable level and thickness who did experience recurrences of metastases. Cell proliferation markers p53, proliferating cell nuclear antigen (PCNA), and Ki-67 were assessed by immunohistochemistry. DNA ploidy was determined by flow cytometry. There was no difference in the expression of p53, PCNA, and Ki-67 between patients with metastases and patients without metastases. However, patients with metastases were more likely to have an aneuploid tumor cell population than were patients without metastases (p < 0.03). Expression of cell proliferation markers do not appear to help predict prognosis in advanced level melanoma; however, aneuploidy may be associated with a greater probability of metastasis.

Myoid cell proliferation in rat seminiferous tubules after ischaemic testicular atrophy induced by epinephrine. Morphometric and immunohistochemical (bromo-deoxyuridine and PCNA) studies

The proliferation of peritubular myoid cells in the testes of rats treated for 1-11 weeks with intra-scrotal injections of epinephrine was investigated using immunohistochemistry and quantitative histology. The percentage of peritubular cells that were immunopositive for proliferating cell nuclear antigen (PCNA) or that were labelled with 5'-bromodeoxyuridine (BrdU) in the S-phase of the cell cycle, were calculated in control and treated rats after 1,3,5,8 and 11 weeks of treatment. In addition, the change in the number of peritubular cells per testis was calculated using two different stereological methods. The possible correlation between the changes observed using the two proliferation indices (PCNA immunoreaction and labelling of BrdU) in peritubular myoid cells was evaluated by regression analysis. The results of the study indicate that both proliferation indices increased in peritubular cells between the third and the eighth weeks of treatment, and that this increase was correlated with an increase in the number of these cells. From weeks 8-11 of treatment, both proliferation indices decreased and the same occurred with the number of peritubular cells. We hypothesize that proliferation of the peritubular cells occurs in order to increase their secretion of extracellular matrix components leading to enlargement of the lamina propria of the seminiferous tubule.

Proliferating cell nuclear antigen may be superior to argyrophilic nucleolar organizer regions in predicting shortened survival of patients with non-small cell lung cancer

We examined proliferating cell nuclear antigen (PCNA) in 102 patients with surgically treated non-small cell lung cancer (NSCLC). PCNA labelling index (LI) tended to be higher in tumours of higher stages than those of early stages, in squamous cell carcinomas than adenocarcinomas, or in poorly differentiated adenocarcinoma than in well-differentiated. A positive correlation was observed between the PCNA LI and argyrophilic nucleolar organizer regions (Ag-NOR) count which we previously examined (r = 0.31, P = 0.002). In survival analysis of 79 patients who died of lung cancer, only age, stage and PCNA LI were found to be significant prognostic factors on multivariate analysis among seven potential prognostic factors including sex, age, year of operation, histological type, stage, Ag-NOR count, and PCNA LI. We conclude that PCNA may be superior to Ag-NOR in predicting shortened survival of patients with non-small cell lung cancer. PCNA staining can be performed with ease and it may be applied in a clinical laboratory on a routine basis to help predict prognosis of NSCLC.

Assessment of cellular proliferation of eccrine acrospiromas and eccrine sweat gland carcinomas by AgNOR counting and immunohistochemical demonstration of proliferating cell nuclear antigen (PCNA) and Ki-67

Argyrophil nucleolar organizer regions (AgNORs) were counted and immunostaining using antibodies raised against proliferating cell nuclear antigen (PCNA) and Ki-67 was carried out on eccrine acrospiroma and eccrine sweat gland carcinoma, to determine the malignant potential and prognosis of these tumours. Formalin-fixed and paraffin-embedded tissue specimens surgically excised from 25 patients with eccrine sweat gland carcinoma (20 cases of eccrine porocarcinoma, four cases of ductal sweat gland carcinoma and one case of malignant clear cell hidradenoma) and 25 patients with eccrine acrospiroma (16 cases of eccrine poroma, four cases of poroid hidradenoma and five cases of clear cell hidradenoma) were used. PCNA and Ki-67 labelling indices were categorized semiquantitatively into four grades. Significant differences were noted between eccrine sweat gland carcinoma and eccrine acrospiroma with these three methods (P < 0.01). When a cut-off of 5 was chosen, the AgNOR value distinguished eccrine sweat gland carcinoma from eccrine acrospiroma with high specificity and sensitivity. Moreover, we compared the results of these three methods between stages 1 or 2 (17 cases) and stage 3 (eight cases) eccrine sweat gland carcinomas, and no significant differences were observed. From these findings, these three methods are useful in discriminating malignant from benign lesions of eccrine tumours, but have no value in estimating the aggressiveness of eccrine sweat gland carcinomas.

Prognostic significance of nucleolar organizer regions (NORS) in malignant melanoma

Nucleolar organizer regions (NORs) are loops of ribosomal DNA (rDNA) in the nucleolus and are associated with acidic proteins. They are seen in routinely processed paraffin sections by using a one-step colloidal silver (Ag) staining method; they appear as black dots termed "AgNORs". The quantitative assay of AgNORs has been used to differentiate benign from malignant neoplasms. Melanocytic lesions differ significantly in AgNOR counts between malignant melanoma and nevi. However, conflicting results have been reported as to AgNORs' prognostic value in melanoma. A recent study showed AgNOR counts to be a more accurate prognostic indicator than Breslow's thickness. In this study, we counted the AgNORs in 26 patients with primary cutaneous melanomas (CMM) between 2.0 mm and 2.5 mm thick. Of these, 14 are alive without disease (AN) at 5 years after diagnosis (group 1) and 12 are dead of disease (DD) in less than 5 years (group 2). The AgNORs were scored in 30 nuclei per tumor, and the means were calculated. For group 1, the mean number of AgNORs per nucleus was 6.88, ranging from 3.73 to 12.70. For group 2, the mean number was 6.97, ranging from 3.63 to 11.67. Statistical analysis using analysis of variance (ANOVA) showed no significant difference between the groups (p = 0.33). In our study, AgNOR counts did not prove to be of prognostic value in malignant melanoma.

Quantification of hepatocytic proliferation in the laboratory mouse. A comparative study using immunohistochemical detection of bromodeoxyuridine (BrdU) incorporation and proliferating cell nuclear antigen (PCNA) expression

The proliferation rate in livers of 120 mice (60 males and 60 females) was analyzed by immunohistochemical detection of bromodeoxyuridine (BrdU) incorporation and proliferating cell nuclear antigen (PCNA) expression on ethanol-fixed/paraffin-embedded specimens. Mice were divided into three groups, with 20 males and 20 females in each group: mice in the first group served as controls, while mice in the second and third groups were treated with a low and a high dose, respectively, of a non-genotoxic drug candidate for 2 weeks. A dose-related increase of the proliferating hepatocyte fraction was disclosed by both immunohistochemical methods, reaching statistical significance already in the low-dose male group for BrdU incorporation and in both male and female low-dose groups for PCNA expression. A good correlation between the degree of BrdU and PCNA labeling was observed and, as expected, the percentage of PCNA expressing cells was generally higher than the percentage of BrdU-positive cells. We concluded that the detection of PCNA expression represents a reliable method for the quantification of the hepatocytic proliferating fraction in rodents and allows the use of archival material for cell kinetic investigations in toxicologic pathology.

Nucleolar organizer regions and PCNA expression in prostatic cancers

Argyrophilic nucleolar organizer regions (AgNOR) of 79 prostatic adenocarcinomas, and an immunohistochemical stain using a monoclonal antibody against proliferating cell nuclear antigen (PCNA) of 54 prostatic adenocarcinomas, obtained by needle biopsy and transurethral resection of the prostate between 1986 and 1989, were investigated. A morphological classification was devised to count silver dots based on the relations between intra- and extra-nucleolar AgNOR (type A, B, C and D). Total AgNOR counts were significantly higher in carcinoma (4.2 +/- 1.57) than in the benign prostatic lesions (1.90 +/- 0.24). Count differences of AgNOR were evident in histological differentiation, nuclear anaplasia, and presence of nucleoli, mitosis, lymphatic invasion and vascular invasion. Higher total AgNOR counts were almost always associated with type B and C AgNOR (intranucleolar AgNOR), but were not associated with type A (nucleolus without small dot) nor type D (extra-nucleolar AgNOR). This study shows the diagnostic value of AgNOR in prostatic cancer, and the importance of morphological classification of AgNOR. The survival of patients with higher AgNOR counts (> or = 4.3) was significantly poorer than survival of those with lower AgNOR counts (< 4.3). Significantly more PCNA positive cells were identified in cancer by immunohistochemical stain and correlated with the presence of mitosis, but there was no significant difference in survival rate groups classified by PCNA positivity. It is also suggested that PCNA can be a useful marker of cell proliferation in prostatic lesions, but the AgNOR counts were diagnostically and prognostically more valuable than immunohistochemical PCNA in prostatic lesions. The correlation between AgNOR and PCNA immunoreactivity was not significant.

Prognostic significance of PCNA grade in malignant melanoma

Proliferating cell nuclear antigen (PCNA) grade (a semi-quantitative assessment of the entire tumor profile) and estimation whether PCNA grade is low (0-50% positive cells) or high (51-100% positive cells) has been demonstrated to be of prognostic significance in gastric carcinoma. Sixteen vertical growth phase melanomas with 8 or more years of clinical follow-up were reacted with antibody to PCNA. PCNA grade was independently evaluated by both authors without knowledge of clinical outcome. PCNA grade was subsequently correlated with clinical outcome and other prognostic indicators. Agreement in assigning PCNA grade was noted between the two observers in 13/16 cases. However, PCNA grade failed to accurately predict patient survival or death. Additionally, PCNA grade was not significantly correlated with other recognized prognostic attributes. While interpretation of the prognostic significance of PCNA grade based upon this small series of cases should be conservative, a semi-quantitative estimate of PCNA-positive cells appears to have little utility in predicting the clinical outcome in malignant melanoma.

Comparison of proliferative activity as assessed by proliferating cell nuclear antigen (PCNA) and Ki-67 monoclonal antibodies in melanocytic skin lesions. A quantitative immunohistochemical study

Immunostaining with the monoclonal antibodies PCNA and Ki-67 provides a simple method for the assessment of growth fractions of tumors. Contrary to Ki-67, PCNA antibody can be applied on aldehyde- or alcohol-fixed and paraffin-embedded tissues, thus allowing studies on archival material. For 77 melanocytic skin lesions, we compared PCNA immunostaining on formalin-fixed tissue with Ki-67 immunostaining on frozen material of the same lesion. 16 benign melanocytic nevi (BMN, from 16 patients), 43 primary malignant melanomas (PMM, 42 patients), and 18 skin metastases of malignant melanoma (MMM, 12 patients) were included in the study. Maximum nuclear density (NDmax) of PCNA- and Ki-67-positive nuclei was assessed using interactive image analysis. NDmax values for both PCNA and Ki-67 differed significantly between the three diagnostic groups (Kruskal-Wallis H-test: p << 0.001). Mean values (given as 1000 nuclei/mm3 tissue) increased considerably from benign to malignant lesions (PCNA: BMN: 23.8 +/- 28.4 [mean +/- standard deviation], PMM: 48.1 +/- 41.0, MMM: 117.0 +/- 64.6; Ki-67: BMN: 6.4 +/- 3.3, PMM 25.0 +/- 31.1, MMM: 95.2 +/- 47.2). Correlation between NDmax values of PCNA- and Ki-67-positive nuclei was significant (Linear regression analysis: r = 0.51, p << 0.001). Furthermore, for PMM a significant correlation between histologic parameters related to prognosis (Breslow index and mitotic rate) and PCNA as well as Ki-67 expression was found (PCNA-Breslow index: r = 0.42, p < 0.01; Ki-67-Breslow index: r = 0.60, p << 0.001; PCNA-mitotic rate: r = 0.40, p < 0.01; Ki-67-mitotic rate: r = 0.50, p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)