Expression of p120, Ki-67 and PCNA as proliferation biomarkers in imprint smears of prostate carcinoma and their prognostic value

The cell proliferation markers p120, Ki-67 and proliferating cell nuclear antigen (PCNA) recognize nuclear antigens. The expression of these proteins by immunostaining methods was reported to be of value in determining the prognosis of patients with malignant diseases. In this study, we evaluated the prognostic significance of the expression of nuclear antigens p120, PCNA and Ki-67 in prostate cancer and compared the results with other prognostic factors. Imprint smear samples obtained from 70 patients immediately after radical prostatectomy for prostatic carcinoma were immunostained with monoclonal antibodies against p120, Ki-67 and PCNA. The immunostaining results were correlated with Gleason score, tumour differentiation, stage and prostatic specific antigen (PSA) levels. Our findings demonstrate that p120, Ki-67 and PCNA expression in prostatic carcinoma smears, correlated significantly with the degree of Gleason score (P < 0.001). When combining p120, Ki-67 and PCNA positivity with tumour differentiation there was a significant association among these parameters (P < 0.001). Overexpression of p120, Ki-67 and PCNA, was also associated with increased PSA serum levels (>4 ng/ml) (P < 0.001). The distribution of p120, Ki-67 and PCNA expression in prostate carcinomas was not statistically significant for Ki-67 (P = 0.69) and p120 (P = 0.22) but was significant for PCNA (P < 0.001) as far as the histological stage (T2a, T2b, T2c, T3a). P120, Ki-67 and PCNA expression had significant prognostic value for disease-free survival. Our results conclude that nuclear antigens p120, Ki-67 and PCNA appear to be additional markers in the field of prognosis of prostatic carcinoma.     

Flow cytometric multiparameter analysis of proliferating cell nuclear antigen/cyclin and Ki-67 antigen: a new view of the cell cycle

Flow cytometric multiparameter analysis of two proliferation-associated nuclear antigens (proliferating cell nuclear antigen (PCNA)/cyclin and Ki-67) was performed on seven human hematopoietic cell lines. PCNA/cyclin, an S phase-related antigen, was detected using an autoantibody and a fluorescein isothiocyanate-labeled anti-human antibody. The Ki-67 antigen, which in cycling cells is expressed with increasing levels during the S phase with a maximum in the M phase, was detected using a monoclonal antibody and a phycoerythrin-conjugated anti-mouse antibody. In some experiments the PCNA/Ki-67 staining was combined with a DNA stain, 7-amino actinomycin D, and simultaneous detection of the three stains was performed by a single laser flow cytometer. Using this technique four distinct cell populations, representing G1, S, G2, and M, respectively, could be demonstrated in cycling cells on the basis of their PCNA/cyclin and Ki-67 levels. The cell cycle phase specificity could be verified using metaphase (vinblastine, colcemide) and G2 phase (mitoxantrone) blocking agents, as well as by stainings with a mitosis-specific antibody (MPM-2). Also, G0 cells could be discriminated from G1 cells in analysis of a mixture of resting peripheral mononuclear blood cells and a proliferating cell line. This technique can be valuable in detailed cell cycle analysis, since all cell cycle phases can be visualized and calculated using a simple double staining procedure.     

Image analysis of in situ cell cycle related changes of PCNA and Ki-67 proliferating antigen expression

Abstract. This study reports on the proliferating cell nuclear antigen (PCNA) and Ki-67 cell cycle related expression and distribution pattern analysed in the same cells. MCF-7 cells were synchronized by mitotic detachment and triple stained for DNA, PCNA and Ki-67. The major cell type was identified on each time sample as a function of the PCNA/Ki-67 pattern, and both antigens as well as DNA were quantified. During G₁ phase, the expression of PCNA greatly increased whereas Ki-67 content decreased. During S phase, nuclear Ki-67 content continuously increased especially in the second half of this phase, mainly due to the accumulation of the antigen in the nucleoli. During G₂ phase, the antigen significantly passed into the nucleoplasm, its content continued to increase and reached its maximum in mitotic cells. Nuclear PCNA content mostly increased in the first part of S phase and sharply declined in mitotic cells as the antigen shifted to the cytoplasm. Cells showing PCNA positive Ki-67 negative labelling were observed in all time samples from the beginning of the experiment. Their nuclear size, DNA content (of G₁ cells), PCNA content (equivalent to the content of some late G, cells) and time occurrence (their percentage increased after the last late G₁ cells had disappeared) tend to indicate that these cells have left the cycle by the end of G₁ phase to enter a quiescent state. Cells coming out of mitosis split into two groups according to their Ki-67/PCNA content. The biggest fraction was PCNA negative and Ki-67 positive while the smallest showed positive staining for both antibodies. Cells of this second cohort slowly lost their 1–67 while their PCNA content increased as they moved through G₁. Concurrently, most of the cells of the first cohort (here called Q2 and Q3 cell types) lost their Ki-67 without increasing their PCNA content; then they joined cells of the second cohort by increasing their PCNA content at the end of G, phase. Some cells of this first cohort can also increase their PCNA and thus reach cells of the first cohort before the end of G₁ phase. The existence of these two main cell cohorts suggests that cells after mitosis differ in some way that make them progress dlfferently through G₁. Some cells seem to go through early G₁ (G_1a and late G₁ (G_lb) while others may come out of mitosis committed to go through the following cycle by directly entering late G₁ compartment.     

Cell cycle-related proteins: a flow cytofluorometric study in human tumors

We used 2-parameter flow cytometry (FCM) to investigate the relationship between the cell cycle phases and 3 proteins whose expression is known to increase in proliferating cells: the surface antigen transferrin receptor (Trf-r), the "cyclin" (a proliferating cell nuclear antigen, PCNA), and the nuclear antigen recognized by the monoclonal antibody (MoAb) Ki-67. FITC-labeled antibodies against Trf-r, PCNA, and the Ki-67-reactive antigen, as well as propidium iodide-DNA distribution, were simultaneously measured on human leukemia HL-60 and K562, and breast carcinoma MCF-7 cell lines and on fresh human leukemic and glioblastoma cells. The 70% ethanol fixation for Trf-r and PCNA and the 95% acetone fixation for Ki-67 plus permeabilization (with 0.1% and 1% Triton X100, respectively, for the surface and the nuclear antigens) produced cell suspensions with negligible cell clumping, high-quality DNA profiles, and bright specific immunofluorescent staining. The investigated proteins have different relationships with the proliferative state of the cell. Trf-r is expressed mainly at the transition from G0/G1 to S-phase. PCNA expression is prominent in late G1 and through S-phase and decreases in G2-M. The Ki-67-reactive antigen is widely distributed in G1, S, and G2-M phases. Knowledge regarding the relationships between proliferation-associated antigens and cell cycle phase in normal and neoplastic cells could improve our understanding of the mechanisms underlying growth regulation and neoplastic transformation. Bivariate FCM is an easy method for obtaining these data from large numbers of cells.     

Measurement of cell proliferation in gastric carcinoma: comparative analysis of Ki-67 and proliferative cell nuclear antigen (PCNA)

Summary Immunostaining to identify nuclear antigens expressed throughout the cell cycle provides a convenient way of assessing proliferating kinetics in tumours. We studied proliferation activity of gastric carcinomas by Ki-67 and PCNA immunostaining and the two methods were compared. The mode of tissue preparation differed, fresh frozen for Ki-67 and formalin-fixed paraffin-embedded for PCNA. Immunostaining with avidin-biotin was used in both. The labelling index (LI) and a semi-quantitative grading of cell proliferation were assessed in both markers. Significant correlation was shown between LI and grading with either Ki-67 and PCNA. However, no correlation was found between PCNA and Ki-67. This lack of relationship between the two markers may be attributed to a number of factors. 1. The most likely is the marked inter- and intra-tumour heterogeneity of gastric carcinomas reflected in high standard deviation values. 2. Preparation of tissue and small size sampling with Ki-67. 3. Long life of PCNA leading to detection of cells that have recently left the cell cycle. 4. One may be observing deregulated expression of DNA as seen in certain tumours. PCNA offers the advantage of being applicable to archival material.     

Proliferating cell nuclear antigen and Ki-67 antigen expression in human haematopoietic cells during growth stimulation and differentiation

Abstract. By flow cytometric dual parameter analysis of proliferating cell nuclear antigen (PCNA) and the Ki-67 antigen a detailed cell cycle analysis can be performed. In this study the co-ordinated expression of these two growth-related antigens was investigated in human haematopoietic cells at entrance into the cell cycle as well as at exit from the cycle. In mitogen-stimulated peripheral blood lymphocytes entering the first cell cycle, the Ki-67 antigen was found to be expressed in S phase cells and not in G₁ cells. Thus, the Ki-67 antigen expression in PCNA-positive S phase cells differed between continuously cycling cells and cells entering the cell cycle. Based on this difference, it was possible to visualize and evaluate the recruitment of cells into the first cell cycle from a resting stage. This new cell cycle parameter can give additional information concerning tumour growth. The Ki-67 antigen was also studied during different stages of G₁ and was found to be expressed at high levels in early G₁ cells compared with other parts of G₁.     

Washless double staining of unfixed nuclei for flow cytometric analysis of DNA and a nuclear antigen (Ki-67 or bromodeoxyuridine).

Washless methods for double staining of nuclear antigen and DNA in unfixed nuclei were compared with established methods for staining of fixed cells. The methods were tested on phytohemagglutinin (PHA)-stimulated normal human blood lymphocytes for the double staining of 1) Ki-67 antigen and DNA and 2) bromodeoxyuridine (BrdUrd) and DNA, in continuously BrdUrd-labeled cells. With respect to the discrimination between antigen-positive and -negative subpopulations, there was no statistically significant differences between the results from direct (Ki-67) or indirect (Ki-67 or BrdUrd) washless staining of unfixed nuclei and the results from staining of fixed cells. Washless staining of unfixed nuclei was found to be rapid and simple and resulted in greater precision of the DNA analysis and in less aggregation and loss of cells.     

Cell proliferation in prostatic carcinoma: comparative analysis of Ki-67, MIB-1 and PCNA

Summary Antibodies to assess the proliferative index of tumours are being increasingly employed together with established markers for prognostic evaluation. This study set out to compare three cell proliferation markers, Ki-67, MIB-1 and PCNA, utilizing a semiquantitative method of assessment, in 20 human prostatic carcinomas. The streptavidin-biotin immunostaining system was used for the monoclonal antibodies MIB-1 and PCNA and an indirect immunoperoxidase assay for the monoclonal antibody Ki-67. Significant correlations were found between the expression of Ki-67 in frozen tissues and MIB-1 in formal saline-fixed wax-embedded tissues (p = 0.0003); between Ki-67 and PCNA expression in Bouin's-fixed tissues (p </ 0.0001); and MIB-1 (formalin-saline-fixed tissues) and PCNA (Bouin's-fixed tissues) (p </ 0.0001). A more intense nuclear staining pattern with less heterogeneity was observed for MIB-1 compared with PCNA, suggesting the antibody of choice, on formal saline-fixed tissues, is MIB-1, which closely correlated with Ki-67, a marker we have previously shown to be of prognostic value in prostatic carcinoma.     

Evaluation of immunohistochemical markers of germ cells' proliferation in the developing rat testis: a comparative study

Germ cells' proliferation during testicular organogenesis in Wistar rat embryos and neonates [14.5, 18.5, 20.5 days post conception (dpc), birth (day 0), 1, 3, 5, 7 days post partum (dpp)] was evaluated via immunohistochemistry, using the PCNA and Ki-67 nuclear antibodies. Estimation of the reactive/total cell ratio, per visual field [labeIing index (LI)] was achieved using the Image Pro Plus Software. Immunostaining of the fetal testis, with both antibodies, revealed increasing germ cells' numbers between 14.5 dpc and birth. From birth onwards, a sharp decline of germ cells' population was observed in the first 3 days of postnatal life. Then, a transient increase of the LI, between 3 and 5 dpp, was noted. Afterwards, proliferation of germ cells ceased. These results indicate that, during fetal and neonatal life, two peaks of proliferative activity of germ cells are noticed. Following estimation of the LI for both PCNA and Ki-67, a prominent labeling for the first antibody was observed throughout the examined period. Ki-67 staining follows a similar pattern, showing, however, significant fluctuation in the obtained values, in comparison to PCNA. The significant differences observed don't seem to be simply a result of the different half lives of the two markers, but rather a consequence of additional underlying cellular activity associated with PCNA, such as DNA repair.     

PCNA、Ki67 在胰腺疾病中的研究进展

PCNA、Ki-67是与细胞增殖有关的核抗原,在增殖的组织细胞中呈阳性表达,反映组织细胞的增殖活性,是细胞增殖的重要标记物。PCNA、Ki-67在正常发育的胚胎组织、糖尿病、胰腺肿瘤、胰岛移植等胰腺疾病及其他疾病中均高表达,同时也与其他系统肿瘤和疾病密切相关。PCNA、Ki-67作为增殖指标可以用于评价胰腺疾病、胰岛细胞移植后细胞再生数量及其他疾病的诊断、治疗及判断预后。目前已将它们视为细胞的标志物,用于细胞增殖的动力学研究,在临床病理上具有很大的应用前景。未来PCNA、Ki67将广泛应用于临床及基础研究,尤其用于研究胰腺疾病的新靶点、探索糖尿病的发病机制,对疾病的预防和治疗及胰岛移植具有一定的应用前景及意义。     

Proliferating cell nuclear antigen in normal urothelium and urothelial lesions of the urinary bladder: a quantitative assessment using a true color image analysis system

To evaluate proliferating cell nuclear antigen (PCNA) staining for assessing proliferative activity in routine pathology specimens of urinary bladder, the bladder carcinoma cell line J82 and a total of 122 specimens of normal bladder and urothelial lesions were stained with the antibody clone PC10 against proliferating cell nuclear antigen. In in vitro plateau cultures the proportion of PCNA-positive cells exceeded that of Ki-67-positive cells, and only very few cells were negative. In formalin-fixed tissues, the PCNA staining pattern, which should be confined to replicon units in the nucleus, was optimized by 1 h postfixation in an organic solvent (methacarn). Sections showed positive nuclear staining confined to basal and some suprabasal cells in normal urothelium and grade 1 dysplasias, but more generalized nuclear staining in all other neoplastic lesions. In addition, stromal cells adjacent to invasive tumors showed nuclear positivity in some instances. Using quantitative true color image analysis of sections counterstained with hemalum, the degree of brown staining of the PCNA reaction product is contrasted with the blue staining of the nuclear area. With this method low contrast specific staining not appreciated optically can be reliably detected. Image analysis data confirmed observations made on noncounterstained sections and showed significant differences between grade 1 and 2 dysplasias as well as between grade 1 dysplasia and all grades of papillary tumor. Furthermore, a significant difference in PCNA staining indices was found between grade 1 and 3 bladder carcinomas. The results indicate that PCNA staining using the PC10 antibody is not confined to the proliferative fraction of neoplastic urothelium. In contrast with data from normal tissue and malignant hematological neoplasms, the amount of PCNA is regulated differently in urothelial neoplasms, emphasizing the biological differences between the following two sets: mild dysplasia and moderate dysplasia; mild dysplasia and papillary carcinomas. The use of image analysis to standardize the detection process after controlled staining conditions is advisable in order to provide reliable data. Supported by the DFG project: Knuechel/Urothelcarcinom 263     

Simultaneous flow cytometric analysis of surface markers and nuclear Ki-67 antigen in leukemia and lymphoma

The monoclonal antibody Ki-67 identifies an antigen present during the late G1, S, G2, and M phases of the cell cycle, whereas resting cells do not express this antigen. Immunostaining with Ki-67 provides a simple method with which to determine the growth fraction of a malignant cell population without requiring a laborious procedure or use of radioactive materials. Thus far, detection of Ki-67-positive cells by flow cytometry was limited because of nuclear location of the antigen. In this study, periodate-lysine-paraformaldehyde (PLP) fixation of cells in suspension, labeling with Ki-67, and the subsequent flow cytometric analysis of the tumor growth fraction is described. Fixation with PLP at -10 degrees C for 15 min rendered the plasma membrane permeable without destroying cell surface antigens. Thus double immunofluorescence studies using both a surface marker and Ki-67 could be performed. This offers the additional advantage of being able to define the phenotype of proliferating cells. This method was applied to determine the growth fraction in peripheral blood and bone marrow samples of patients with leukemia and non-Hodgkin's lymphoma. The results of Ki-67 studies in 91 patients are shown. A wide variability of individual Ki-67 values was observed within each entity. Use of this flow cytometric procedure substantially facilitates the quantification of proliferating cells in pathological blood and bone marrow samples.     

Cyclin D1 Immunoreactivity in Meningiomas

Objective Cyclin D1 is an important nuclear protein required for progression of cells through the G1 phase of the cell cycle. The proliferative potential of meningiomas has been studied using various proliferative markers. However, there have been only few published studies evaluating Cyclin D1 immunoreactivity in meningiomas. Purpose of the study The aim of our study was to analyze the Cyclin D1 expression in meningiomas and correlate it both with proliferation markers Ki67 and PCNA, and with meningiomas of WHO grade. Material and methods We evaluated immunoreactivity for proliferative markers (Cyclin D1, Ki-67, and PCNA) in a consecutive series of 64 meningioma samples obtained from patients who underwent surgical resection because of cerebral or spinal meningiomas. Immunohistochemical staining with Ki-67, PCNA, and Cyclin D1 was performed using the microwave processing procedure and LSAB+ methodology. The number of positive cells for each antibody has been determined and shown in percentage in relation to 1000 counted cells. Results All meningioma samples showed immunostaining for Ki-67, PCNA, and Cyclin D1 antibodies. The Cyclin D1 scores exhibited a close correlation with Ki-67 and PCNA immunostaining (P < 0.01). Some meningiomas (15 cases) showed a combination of nuclear and cytoplasmatic (fine granular) Cyclin D1 immunoreactivity. All proliferative indexes have been in positive correlation with meningioma grade. Conclusion Our comparative study of proliferative markers in meningiomas demonstrated Cyclin D1 as a very useful proliferative marker in meningiomas.     

Splenic haematopoiesis in primary (idiopathic) osteomyelofibrosis: immunohistochemical and morphometric evaluation of proliferative activity of erythro- and endoreduplicative capacity of megakaryopoiesis (PCNA- and Ki-67 staining)

Using monoclonal antibodies against proliferating cell nuclear antigen or PCNA (PC10) and the Ki-67 antigen (MIB1), an immunohistological and morphometric study was performed on routinely processed splenic tissue from ten patients with primary (idiopathic) osteomyelofibrosis (OMF). To determine the proliferation capacity of erythroid precursors and the endoreduplicative activity of megakaryocytes, corresponding antibodies (Ret40f and CD61) were applied in combination with the cell-cycle markers (sequential double-immunostaining). Morphometric analysis revealed no significant differences in PCNA or Ki-67 reactivity in either cell lineages. In comparison with previous studies on normal bone marrow, in splenic tissue showing myeloid metaplasia, the numbers of PCNA-labelled proerythroblasts, erythroblasts and megakaryocytes were conspicuously increased. Considering the ineffective erythropoiesis in OMF, there seemed to be a disproportional enhancement in PCNA and Ki-67 immunostaining of the red cell lineage. Similarly, the small size of megakaryocytes in advanced, OMF-associated myeloid metaplasia was in keeping with an impairment of endoreduplicative activity. In addition to various other contributory factors, anaemia in OMF may be partially caused by secondary folate (haematinic) deficiency. From experimental studies this defect is known to cause an abnormal arrest in the S-phase of the cell-cycle, comparable to that characterising pernicious anaemia. As a sequel of this pathomechanism, an undue overexpression of PCNA and Ki-67 has to be assumed, that is not necessarily associated with DNA synthesis or cell cycling. This work was supported by a grant from the Deutsche Forschungsgemeinschaft (DFG-Th 390/1-3)     

Effect of ionic strength in immunocytochemical detection of the proliferation associated nuclear antigens p120, PCNA, and the protein reacting with Ki-67 antibody.

This study was aimed at revealing whether or not ionic interactions between the epitope of the antigen detected by Ki-67 antibody, or the proliferation-associated proteins PCNA or p120, and neighboring cellular constituents impede detectability of these antigens in HL-60 cells by indirect immunofluorescence assay. To this end, the ionic strength (NaCl concentration) of the solutions in which cells were suspended during their fixation with 0.5% paraformaldehyde was increased, to up to 1.65 M NaCl, to weaken the intra- and/or intermolecular ionic interactions during the process of crosslinking, and the cells were then immunostained. Fluorescence of cells reacting with Ki-67 antibody was maximally increased after their treatment with 1.15 M NaCl; the average increase was nearly 110% above the level seen with the standard methodology utilizing 0.15 M NaCl. The increase was greater for cells in the G1 phase of the cell cycle compared to cells in S or G2. Fluorescence of cells stained with the PCNA antibody was maximally enhanced after cell treatment with 0.65 M NaCl. The enhancement, however, varied depending on the source of the antibody; it was nearly 200% in the case of the antibody provided by Boehringer and over 100% by DAKO. Detection of the nucleolar antigen p120 was not significantly affected by 0.65-1.65 M NaCl. The data indicate that ionic interactions between cellular constituents indeed play a role in masking the epitope of PCNA and the antigen detected by Ki-67.(ABSTRACT TRUNCATED AT 250 WORDS)     

盐酸酸化可改善核抗原免疫荧光染色

免疫荧光染色(immunofluorescent staining, IF)技术广泛用于细胞或组织内抗原定性、定量或定位检测。然而,依常规染色步骤操作,在有些胞核抗原的检测中很难得到令人满意的结果。有研究者采用盐酸酸化预处理用于细胞增殖标记物5-溴-2-脱氧尿嘧啶核苷(BrdU)的荧光染色并获得良好效果。但此方法是否也适用于其他类型的胞核抗原,尚不清楚。为系统全面分析盐酸酸化在胞核抗原免疫荧光染色中的作用,本文以成年C57BL小鼠主要嗅觉表皮(MOE)为材料,分别对Ki-67、5-甲基胞嘧啶(5mC)和5-羟甲基胞嘧啶(5hmC)三种不同类型的胞核抗原进行盐酸酸化处理免疫荧光染色。结果显示,当血清封闭和抗体浓度等条件一致时,室温下盐酸酸化2 h,Ki-67的染色效果最佳,而阴性对照与未酸化组均未出现阳性信号;同样经过盐酸处理2 h,5mC和5hmC染色也呈现较强的阳性信号。该研究表明,在一些胞核抗原免疫荧光染色中,使用盐酸酸化处理可显著提高染色效果。     

PCNA independence of Ki-67 expression in HPV infection.

12 Infectious Wart lesions were stained using the streptavidin-biotin immunoperoxidase method for PCNA10, MIB-1 (Ki-67 equivalent antigen) and Human Papilloma Virus antigen to study the effect of HPV presence on epidermal proliferation. Using strict methods to avoid observer bias, Ki-67 antigen was found in a high proportion of nuclei in the suprabasal layers together with HPV antigens, in the absence of PCNA staining. This finding indicates that DNA synthesis related, Ki-67 antigen bearing structures can be raised in the human nucleus in the absence of induction of PCNA bearing structures, suggesting also structural independence between the antigen bearing molecules.     

PCNA/cyclin expression and BrdU uptake define different subpopulations in different cell lines.

Monoclonal antibodies (MAb) to a 36 KD protein, proliferating cell nuclear antigen (PCNA/cyclin), have been previously shown to be capable of identifying proliferating cells in vitro as well as in alcohol-fixed, paraffin-embedded tissue specimens. The routine use of these anti-PCNA/cyclin MAb in investigative studies and in diagnostic pathology requires a clearer understanding of the distribution of PCNA/cyclin in the different cell populations found in tissue specimens. We therefore compared the ability of MAb to three nucleus-associated proliferation markers (MAb 19A2 to PCNA/cyclin; Ki-67 to an undefined proliferation-related marker; BU-1 to 5'-bromodeoxyuridine (BrdU) incorporated into DNA) to identify the proliferating cell fraction of various cells in vitro. The cell lines were chosen to represent a spectrum of proliferation rates (high to low) and cell lineage (mesenchymal vs epithelial, non-transformed vs malignant): (a) HeLa and A-431 (two malignant carcinoma cell lines with high proliferation rates); (b) SK-5 (a non-transformed fibroblast cell line with a low proliferation rate); (c) HUVE (a non-transformed human umbilical vein endothelial cell line with a low proliferation rate). Single and double labeling immunofluorescence studies were performed after uniform 1-hr incubations with BrdU. Comparison of the overlapping distributions of detectable PCNA/cyclin expression and BrdU incorporation demonstrated substantial qualitative and quantitative differences between the different cell lines. In two of the four cell lines (HeLa, A-431) the BrdU staining distributions formed inclusive subsets of the PCNA-positive cell populations. In the HUVE cell line the two populations overlapped incompletely. In one cell line, SK-5, the two populations were mutually exclusive. MAb Ki-67 demonstrated a pattern in the SK-5 cell line that was strongly predictive of PCNA positivity, while showing no associated patterns in the other three cell lines. We conclude that PCNA/cyclin expression detected by MAb may define different cell subpopulations in different cell types relative to those incorporating BrdU or expressing the target antigen for Ki-67. This has implications for the clinical study of mixed cell populations using these antibodies.     

Selected markers of proliferation and apoptosis in the parathyroid lesions: a spatial visualization and quantification

The aim of the paper was to apply a method for quantitative assessment of proliferation and apoptosis markers, based on their 3D visualization, in cases of parathyroid adenoma and hyperplasia. Material was obtained from 49 patients (32 females and 17 males) with primary hyperparahyroidism. Quantitative immunohistochemistry studies of Ki-67, proliferating cell nuclear antigen (PCNA) and bcl-2 were performed on digital microscopy images with the use of 3D visualization. The use of spatial visualization method allowed us to perform objective quantitative assessment of the studied immunohistochemical markers. The average cell nuclear fraction of Ki67+ was 1.8% in hyperplasia and 1.9% in adenoma cases while 3.5% in the controls. The highest expression of PCNA was found in parathyroid hyperplasia (22.9%) and significantly decreased in adenoma (12.5%) and in the control group (16.8%). The lower expression of bcl-2 in hyperplasia cases (mean area fraction of 0.172 per 1 μm², in contrast to 0.643 in adenomas and 0.648 in control) suggested that principal cells can be ready for apoptosis and may confirm the important role of bcl-2 protein in etiopathogenesis of hyperplasia of the parathyroid gland while PCNA might be a useful marker for differentiating adenoma from early hyperplasia in primary hyperparahyroidism cases.