Percentage Of PCNA-positive Cells Research Articles

Quantitative Analysis of Extracellular Matrix Proteins in Hypertrophic Layers of the Mandibular Condyle and Temporal Bone during Human Fetal Development

A computer image analysis of immunostained extracellular matrix (ECM) proteins (collagen types I, II, III and V, fibronectin and tenascin) in hypertrophic layers in the mandibular condyle and temporal bone of human fetuses, which ranged in gestational age from 12 to 32 weeks, was performed. The percentage of cells positive for proliferating cell nuclear antigen (PCNA) increased in almost the same manner in each region. The level of PCNA was markedly elevated at 16 weeks. The percentage of PCNA-positive cells was low in temporal bone and in the bone-forming layer of the mandibular condyle at 24 weeks. Specific concentration patterns of proteins in the ECM were found at each stage of development. The extent of accumulation of fibrillar collagen and of fibronectin differed, while those of other proteins in the ECM, such as tenascin, osteocalcin and osteonectin, were similar at the two sites.

Transforming growth factor alpha (TGFα) in hepatocellular carcinomas and adjacent hepatic parenchyma

We examined stage T1 to T4 hepatocellular carcinomas (HCC) to determine whether transforming growth factor alpha (TGFα) presence differed between early- and late-stage HCC and between tumors with low and high proliferative rates. Paraffin sections from 36 HCC were evaluated for TGFα and the proliferation markers Kiel 67 antigen (Ki67) or proliferating cell nuclear antigen (PCNA) by immunoperoxidase staining. In 12 cases, double staining for TGFα and Ki67 was also performed. Eighty-one percent of tumors and 94% of adjacent liver sections contained TGFα. A trend toward inverse correlation was seen between the percentage of TGFα-positive tumor cells and the proliferative rate as determined by Ki67 staining. No clear correlation of TGFα to either tumor stage or percentage of PCNA-positive cells was seen. This study confirms the presence of TGFα in the majority of early- and late-stage HCC. Positivity within tumor tissue is consistent with autocrine or paracrine stimulation. A trend toward inverse correlation between TGFα-producing cells and the number of cycling cells suggests that rapidly proliferating tumors may consume this growth factor at an accelerated rate. Alternatively, other hepatic mitogens may have more functional significance in these latter tumors. Finally, the presence of TGFα in peritumoral hepatocytes suggests these cells as potential sources of paracrine stimulation for HCC.

The Value of PCNA and AgNOR Staining in Endoscopic Biopsies of Gastric Mucosa

The aim of the present study was to examine the usefulness of the quantification of PC10-positive-cells and of Argyrophilic Nucleolar Organizer Regions (AgNORs) in gastric biopsies for the identification of gastric mucosal proliferative lesions. Fifty seven paraffin-embedded endoscopic biopsies were classified into four histologic groups: normal, inflammatory, dysplastic and neoplastic mucosa. The percentage of PC10-positive cells was determined by immunohistochemistry. The AgNOR parameters determined included the total number of all identifiable silver precipitations in the nucleus, the mean number of silver precipitations per cluster, and the presence of morphologically heterogenous silver precipitations. Group comparisons were performed using the Kruskall Wallis and Dunn non-parametric tests with a significance level of 5%. A discriminant analysis (followed by the jack-knife procedure) was performed using the three AgNOR parameters plus the percentage of PCNA-positive cells as the independent variables and histological groups as the dependent variable. All three AgNOR parameters, as well as the percentage of PCNA-stained nuclei, showed their highest values in the carcinoma group. However, no good differentiation among the four histologic groups was obtained using only one of these parameters, since there was always considerable overlap among them. By combining all the parameters in a linear discriminant analysis, we obtained a correct classification in 48 out of 57 cases. Within the classification errors there was only one false positive carcinoma, which was in fact a dysplasia and only one false negative carcinoma erroneously classified as dysplasia. The number of cells with heterogenous AgNORs was the most important parameter for the discriminant analysis. No correlation between PCNA values and the AgNOR parameters could be found, thus indicating that they do not represent the same phenomenon in the cell cycle. We concluded that the use of a combination of various proliferation parameters in a linear discriminant analysis may be helpful for differentiating gastric mucosal lesions. The peculiar AgNOR morphology is an important variable which should be taken in consideration in quantitative studies. PCNA and AgNORs seem to represent different physiological phenomena in the cell cycle.

Immunocytochemical study of the maxilla and maxillary sinus during human fetal development.

We quantitatively examined the distribution of the proliferating cell nuclear antigen (PCNA), which is associated with cell division, and of components of the ECMs (collagen types I and III, tenascin and osteonectin) in the immature zones at three sites: palatine, inferior and vertical surface region of the fetal human maxilla as well as the maxillary sinus (MS) at 12, 16, 20, 24, and 28 weeks gestation. The percentage of PCNA-positive cells was the highest at 16 weeks in the immature zones of maxilla. Tenascin and fibrillar collagens (collagen types I and III) were especially present in the cellular zone linked to the bone and cartilage matrices of the immature zones of the maxillary bone at 20-24 weeks gestation. The osteonectin was detected on the maxillary bone from 24 weeks. These distributions of ECMs revealed the specific and contrasting profiles of development in the human maxillary bone and might reflect the formation of paranasal sinus as MS.

Cell proliferation in the developing human kidney.

In a previous study, utilizing antibodies to proliferating cell nuclear antigen (PCNA), we determined the proliferation index (PI) (percentage of PCNA-positive cells) of intrinsic renal cell populations in the normal adult and pediatric kidney. We have found that the PI in both adult and pediatric kidneys was very low (below 0.5 in all examined cell populations). In our present study, we investigated cell proliferation in the developing human kidney with an antibody to PCNA. Histologically normal kidneys were collected from 25 fetuses (spontaneous abortions and stillborns) ranging from 10 wk of gestation to term. Immature mesenchyme (blastema), immature early tubules, ampulla of ureteric bud, proximal tubules, Tamm-Horsfall protein (THP)-positive tubules, distal tubules, collecting ducts, and glomeruli were evaluated separately. The PI for each cell population was calculated. The PI of immature early tubules remains high (33-43) throughout embryonic life. The PI of blastemal cells is initially similarly high, but gradually decreases starting from the second trimester. The PI of THP-positive tubules, distal tubules, collecting ducts, and glomeruli starts out relatively high (5.9, 8.6, 6.0, and 12.4, respectively) and decreases gradually as term approaches (1.8, 1.3, 1.2, and 1.4, respectively). Interestingly, as soon as proximal tubules become differentiated (appearance of light microscopic features of proximal tubular epithelium with TP lectin positive brush border), their PI becomes very low (below 1) irrespective of the age of the kidney. This is the first quantitative study to show changes of the PI in various renal cell populations during human nephrogenesis. These changes in the PI relate to the stage of differentiation of the developing nephron segments.

Protective action of hepatocyte growth factor for acute liver injury caused by D-galactosamine in transgenic mice.

Hepatocyte growth factor (HGF) has been reported to be a potent mitogen for hepatocytes in vivo and in vitro. Recent reports have shown that HGF has cytoprotective actions in acute liver injury models, but its mechanisms remain to be resolved. In the present study, we investigated whether HGF could work as an anti-hepatitis agent for acute liver injury caused by D-galactosamine (D-GalN) using transgenic (TG) mice expressing HGF in hepatocytes, compared with wild-type (WT) mice of their siblings. After administration of 3 g/kg body weight of D-GalN, elevated serum transaminase levels and severe liver damage that were observed in WT mice were significantly improved in TG mice. In TG mice, the percentage of proliferating cell nuclear antigen (PCNA)-positive hepatocytes was high at 0 hours after D-GalN treatment, and increased at 24 hours. The percentage of PCNA-positive cells in WT mice was very low at 0 hours and 24 hours after treatment, but increased at 48 hours. To clarify the mechanisms via which HGF acts, we measured hepatic HGF and prostaglandin E2 (PGE2) contents after D-GalN administration by an enzyme immunoassay. Total hepatic HGF contents, which were composed of murine (endogeneous) and human (derived from transgene) HGF, in TG mice were higher than those in WT mice at 0, 12, and 24 hours after administration of 3 g/kg body weight of D-GalN. Hepatic PGE2 contents in TG mice were also significantly higher than those in WT mice. Hepatic PGE2 contents had a positive correlation with total HGF contents at both 12 hours and 24 hours after the treatment. Moreover, an administration of 0.5 μg of anti-HGF antibody into the portal vein suppressed hepatic PGE2 contents of mice, compared with saline- injected mice in acute liver injury. Anti-PGE2 antibody administration caused more severe liver damage than saline solution. A survival rate of TG mice that were given 6 g/kg body weight of D-GalN–a lethal dose of D-GalN–was improved compared with WT mice. These results provided direct evidences that HGF worked as an anti-hepatitis agent against acute liver injury caused by D-GalN, and that this action might be exerted through accelerated hepatic PGE2 production. (Hepatology 1997 Nov;26(5):1241-9)

Protective action of hepatocyte growth factor for acute liver injury caused by D-galactosamine in transgenic mice

Hepatocyte growth factor (HGF) has been reported to be a potent mitogen for hepatocytes in vivo and in vitro. Recent reports have shown that HGF has cytoprotective actions in acute liver injury models, but its mechanisms remain to be resolved. In the present study, we investigated whether HGF could work as an anti-hepatitis agent for acute liver injury caused by D-galactosamine (D-GalN) using transgenic (TG) mice expressing HGF in hepatocytes, compared with wild-type (WT) mice of their siblings. After administration of 3 g/kg body weight of D-GalN, elevated serum transaminase levels and severe liver damage that were observed in WT mice were significantly improved in TG mice. In TG mice, the percentage of proliferating cell nuclear antigen (PCNA)-positive hepatocytes was high at 0 hours after D-GalN treatment, and increased at 24 hours. The percentage of PCNA-positive cells in WT mice was very low at 0 hours and 24 hours after treatment, but increased at 48 hours. To clarify the mechanisms via which HGF acts, we measured hepatic HGF and prostaglandin E2 (PGE2) contents after D-GalN administration by an enzyme immunoassay. Total hepatic HGF contents, which were composed of murine (endogeneous) and human (derived from transgene) HGF, in TG mice were higher than those in WT mice at 0, 12, and 24 hours after administration of 3 g/kg body weight of D-GalN. Hepatic PGE2 contents in TG mice were also significantly higher than those in WT mice. Hepatic PGE2 contents had a positive correlation with total HGF contents at both 12 hours and 24 hours after the treatment. Moreover, an administration of 0.5 μg of anti-HGF antibody into the portal vein suppressed hepatic PGE2 contents of mice, compared with saline- injected mice in acute liver injury. Anti-PGE2 antibody administration caused more severe liver damage than saline solution. A survival rate of TG mice that were given 6 g/kg body weight of D-GalN-a lethal dose of D-GalN-was improved compared with WT mice. These results provided direct evidences that HGF worked as an anti-hepatitis agent against acute liver injury caused by D-GalN, and that this action might be exerted through accelerated hepatic PGE2 production.

Increased nuclear ploidy, not cell proliferation, is sustained in the peroxisome proliferator-treated rat liver.

Peroxisome proliferators are believed to induce liver tumors in rodents due to sustained increase in cell proliferation and oxidative stress resulting from the induction of peroxisomal enzymes. The objective of this study was to conduct a sequential analysis of the early changes in cell-cycle kinetics and the dynamics of rat liver DNA synthesis after treatment with a peroxisome proliferator. Immunofluorescent detection of proliferating cell nuclear antigen (PCNA) and bromodeoxyuridine (BrdU) incorporation into DNA during S phase we used to assess rat hepatocyte proliferation in vivo during dietary administration of Wy-14,643, a known peroxisome proliferator and hepatocarcinogen in rodents. Rats were placed on diet containing 0.1% WY-14,643 and implanted subcutaneously with 5-bromo-2'deoxyuridine containing osmotic pumps 4 days prior to being sacrificed on days 4, 11, and 25 of treatment. Isolated liver nuclei labeled with fluorscein isothiocyanate (FITC)-anti-BrdU/PI and FITC-anti-PCNA/PI were analyzed for S-phase kinetics using flow cytometry. Morphometric analysis was performed to evaluate nuclear and cell size and enumeration of BrdU labeled cells, binucleated hepatocytes, and mitotic index. The BrdU labeling index increased 2-fold in livers of Wy-14,643-treated rats at day 4, but distribution of cells in G1, S phase, and G2-M did not differ significantly from controls. PCNA-positive cells decreased from 36% on day 4 to 17% on day 25, whereas the percentage of PCNA-positive cells in controls increased 2-fold from day 4 to day 11 and remained unchanged up to day 25. The differences in the number of PCNA-positive nuclei between control and Wy-14,643-treated groups were statistically significant only on day 4. Binucleated hepatocytes, determined by morphometric analysis, increased slightly on day 25 in treated rats parallel to an increase in the percentage of cells in G2-M phase. Significant shifts were noted in nuclear diameter and nuclear area after 11 and 25 days of treatment with Wy-14,643. Hepatic cell populations with nuclei > 9 microns diameter and nuclear area > 64 microns2 increased in Wy-14,643-fed rats during the treatment period compared with the control, indicating hepatic karyomegaly and hyperploidy, whereas percentage of distribution of nuclei based on diameter and area remained consistently unchanged in control animals from 4 through 25 days of sham treatment. The flow cytometric and morphometric analysis indicated an initial wave of DNA synthesis in response to Wy-14,643. The hepatomegaly was sustained over the treatment period accompanied by increase in ploidy with a significant shift toward hyperploidic hepatocytes. The increase in DNA content was almost entirely accounted for by the overall polypoidy increase rather than by an absolute increase in cells.

Detection of Proliferating Cell Nuclear Antigen (PCNA) in Peripheral Blood Mononuclear Cells and Sera of Patients with Malignant Lymphoma

Proliferating cell nuclear antigen (PCNA) was detected in the peripheral blood mononuclear cells (PBMC) of patients with malignant lymphoma (ML). Twenty-one of 27 patients with ML had PCNA expressing PBMC (5.25 ± 4.75% cells), which tended to increase in the advanced clinical stage of ML. PCNA in PBMC extracts was detected in 11 of 16 patients (54.5 ± 41.9 ng/ml). The percentage of PCNA-positive cells correlated significantly with the concentration of PCNA in PBMC extracts (P < 0.005). Serum PCNA was detected in 6 of 16 patients (160.1 ± 141.1 ng/ml), but did not correlate with the number of PCNA-positive cells. In some cases, the concentration of serum PCNA increased after chemotherapy while the percent PCNA-positive cells decreased. Our finding indicate that detection of PCNA in PBMC appears to help monitoring the extent of disease in ML and the serum PCNA level may be used in therapeutic studies of lymphoma patients.

Prognostic factors in urachal adenocarcinoma: A study in 41 specimens of DNA status, proliferating cell-nuclear antigen immunostaining, and argyrophilic nucleolar-organizer region counts

Few studies have investigated the prognostic value of a variety of cell-biological parameters in cases of urachal adenocarcinoma, a rare neoplasm. The authors examined three cell-biological parameters—DNA status, proliferating cell-nuclear antigen (PCNA) immunostaining, and argyrophilic nucleolar-organizer region (AgNOR) counts—in surgically resected, formalin-fixed, paraffin-embedded urachal adenocarcinomas from 41 patients. The authors quantified DNA distribution in 200 cancer cells from a section of each tumor, stained with 4′,6-diamidino-2-phenylindole, using a microspectrophotometer. The authors also measured the number of PCNA immunostaining cells in 1,000 nuclei, and AgNORs counts in 200 nuclei, from sections of each tumor. There were eight specimens with group 1 DNA distribution (defined as a DNA content of under 4c in >90% of the cells), 21 of group 2 DNA distribution (more than 4c in > 10% of the cells and more than 6c in <10% of the cells), and 12 of group 3 DNA distribution (more than 6c in > 10% of the cells). The percentage of PCNA-positive cells was 19% to 91% (median, 59.5%), and the mean AgNOR count was 2.2 to 8.8 (median, 5.3) granules per nucleus. The 5-year survival rate for all 41 patients was 50.2%. Initial univariate analyses indicated that tumor stage, histological differentiation, and DNA status had a significant effect on survival. In the final models using multivariate analysis, only tumor stage and histological differentiation were found to be prognostic factors. These investigations confirm the vital importance of tumor stage and histological differentiation as predictors of patient survival. The three cell-biological parameters the authors studied do not appear to be important parameters for predicting survival.

Histopathological Changes of Rat Tongue Epithelia Induced by the Administration of Low Iron Diet

In order to clarify the histopathological changes of oral mucosa induced by low iron conditions, rat tongue epithelia in low iron conditions were examined histologically. Sprague-Dawley rats (3 weeks old) were divided into 2 groups. The experimental group (E group n=10) was given a low iron diet (PMI.Test Diet 5895,<5mg Fe/kg diet), while the control group (C group n=10) was fed a standard laboratory diet (NIHON CLEA, CE-II, 347 mg Fe/kg diet). Animals were sacrified after 8 weeks and 18 weeks, and their tongues were removed and histologically analyzed by H-E staining, SEM and histochemistry with anti-PCNA staining. Although histological changes of tongue papilla were not observed, epithelial dysplasia was demonstrated in some rats of E-group, and a significant increase in the percentage of PCNA positive cells in basal and para basal cell layers were observed in E-group when compared with that of C group (65% in E group, 7% in C group, 8 weeks; 50% in E group, 7% in C group, 18 weeks). Our results suggest that the increase in mitotic activity of tongue epithelia can be induced by the administration of a low iron diet.

Differential Image Analysis of Proliferating Cell Nuclear Antigen (PCNA) Expression Level during Experimental Thyroid Carcinogenesis.

Immunostaining of proliferating cell nuclear antigen (PCNA), which can be applied to routinely processed tissue sections, has extended the applications of cell kinetic studies. PCNA immunostaining intensity of cells varies among individual nuclei in tissue sections. To determine the changes in PCNA expression level during carcinogenesis, we employed an image analyzer to evaluate PCNA staining intensity in diisopropanolnitrosamine (DIPN) -induced neoplastic lesions of rat thyroid glands.In the normal thyroid gland, only small numbers of cells showed weak PCNA expression. The percentage of PCNA-positive cells increased during carcinogenesis, i. e. hyperplasia, adenoma, and then carcinoma. Analysis of PCNA staining intensity histograms revealed that the population of cells with stronger intensity increased during carcinogenesis, i. e. from adenoma to carcinoma. However, the percentage of cells with weak PCNA staining increased in hyperplasia, and did not change in intensity during further carcinogenic sequelae. These differences in PCNA expression level recognized by immunostaining intensity may reflect different cell kinetics between the process of hyperplasia and that of differentiation from adenoma to carcinoma.

BENIGN AND MALIGNANT MYOEPITHELIOMA OF SALIVARY-GLAND - AN IMMUNOHISTOCHEMICAL EVALUATION

Three myoepitheliomas (MEOs) derived from the salivary glands were examined immunohistochemically. Proliferating cell nuclear antigen (PCNA)-positive cells were very rare (less than 2% of all tumor cells) in localized tumors of case 1 (epithelioid) (E-oid) cells) and case 2 (plasmacytoid) (P-toid) cells with a small number of spindle-shaped cells), but the percentage of PCNA-positive cells was high (21.8%) in case 3 (clear cells) exhibiting bone destruction. Strong c-myc expression was detected in all the tumors, but p53 or c-erbB-2 protein was not detected in any of the cases. More than half of the clear cells were positive for epidermal growth factor (EGF), while fewer tumor cells in cases 1 and 2 expressed EGF. A few tumor cells in cases 2 and 3 were positive for EGF-receptor (R). Keratin was most prominent in the E-oid cells, The P-toid cells were most strongly positive for S-100 protein followed by the E-oid and clear cells. More than half of the spindle-shaped cells and one-third of the E-oid cells were positive for alpha-smooth muscle actin (alpha-SMA), but less than 5% of the clear cells and none of the P-toid cells were positive for alpha-SMA. These results suggest that tumor cells in MEO are heterogenous and have different proliferation activities.

PROGNOSTIC-SIGNIFICANCE OF PROLIFERATING CELL NUCLEAR ANTIGEN (PCNA) IN ADENOCARCINOMA OF THE LUNG

The aim of the study was to investigate the prognostic value of the proliferating cell nuclear antigen (PCNA) expression in non-small cell lung carcinomas (NSCLC). Two hundred and sixteen patients with previously untreated NSCLC entered into this investigation. For assessment of PCNA expression the streptavidin-biotinylated peroxidase complex method was performed using imnuunohistochemistry and Mab PC10. The tumors were scored for the percentage of PCNA-positive cells (low proliferative activity less than or equal to 25%; high proliferative activity >25%). Univariate analyses of all patients showed a trend that those with high proliferating tumors had shorter survival times than those with lower proliferating tumors. Similar results were obtained when the analysis was restricted to squamous cell carcinomas. Patients with adenocarcinomas and with high proliferating tumors had significantly shorter survival times than those with low proliferating tumors (p=0.028). No correlation was found between extent of tumors or metastasis and expression of PCNA. The multivariate analysis including age, sex, extent of tumors and metastasis as well as PCNA revealed a highly significant influence of extent of tumors (p=0.007) and metastasis (p=0.003) whereas all other factors including PCNA were of no significant influence.

短期間のうちに形成された歯原性角化嚢胞の１例

Odontogenic keratocyst is histologically and clinically distinct from other odontogenic cysts, especially with regard to its high recurrence rate and the remarkable growth capacity.We report a case of a 19-year-old man with an odontogenic keratocyst of the mandible. Radiographic findings showed that a cyst measuring 50×30mm developed during 1 year 6 months, and the growth rate was about 33mm per year.Proliferating cell nuclear antigen (PCNA) expression was also analyzed. Histopathologically, the cyst was lined by a relatively thick layer of parakeratinized epithelium, and partially deep prolongation of the epithelium was observed. A daughter cyst was not present.Immunohistochemically, staining using monoclonal antibody to PCNA revealed that the percentage of PCNA-positive cells in the odontogenic keratocyst lining (11.2%) was about twice that in the normal gingiva (4.6%). In the odontogenic karatocyst lining, PCNApositive cells were more often found in prickle cells than in basal cells.At present, there are no signs of recurrence as of 1 year 6 months after operation.

Growth rate of intracranial meningioma: tumor doubling time and proliferating cell nuclear antigen staining index.

The relationship between tumor doubling time, estimated by serial computed tomography (CT), and the proliferating cell nuclear antigen (PCNA) staining index of the tumor specimen was analyzed in 12 patients with nine partially or subtotally resected meningiomas and three meningiomas which recurred after gross total removal. There were nine meningothelial and three fibrous meningiomas. Malignant meningiomas and hemangiopericytomas were excluded. Serial CT was performed at various intervals ranging from 354 to 2007 days. Formalin-fixed, paraffin-embedded archival tissues were immunohistochemically stained using the avidin-biotin complex method with monoclonal antibody against PCNA. Percentages of PCNA-positive cells were calculated in 10 microscopic fields to determine the mean PCNA staining index. PCNA staining indexes varied from 0.13% to 7.46%. The tumor doubling time ranged from 197 to 7943 days and demonstrated a significant inverse rank correlation with the PCNA staining index (r = -0.89, p = 0.003). Meningiomas with PCNA staining indexes higher than 1% have comparatively short tumor doubling times of less than 5 years. PCNA immunostaining is a useful method for evaluating the proliferative activity of meningiomas.

Expression of the proliferating cell nuclear antigen in cervical neoplasia.

The expression of the proliferating cell nuclear antigen (PCNA) was examined to determine the proliferative activity of the cells in nonneoplastic and neoplastic lesions of the uterine ectocervix. Formalin-fixed, paraffin-embedded tissue sections of uterine cervix including normal, metaplasia, condyloma, intraepithelial neoplasia and invasive squamous cell carcinoma were stained immunohistochemically using monoclonal antibody to PCNA. The percentage of PCNA-positive cells was significantly higher in premalignant and malignant lesions of the uterine cervix than in nonneoplastic lesions. Furthermore, the growth fraction of tumor cells as detected by PCNA was increased in accordance with the progression of neoplasia. The results of this study suggest that the cell proliferation index as detected immunohistochemically using PCNA may be a useful adjunct to histological diagnosis of various grades of dysplasia.

Proliferative cell nuclear antigen expression in follicular tumours of the thyroid with special reference to oxyphilic cell lesions.

The expression of proliferative cell nuclear antigen (PCNA) in follicular tumours of the thyroid was examined by immunohistochemistry. Both usual nonoxyphilic cell follicular tumours (non-OCT) and oxyphilic cell tumours (OCT) were subdivided into benign, indeterminate, encapsulated carcinoma, and widely invasive carcinoma types. Among non-OCT the percentages of PCNA-positive cells in benign tumours, encapsulated carcinomas, and widely invasive carcinomas was 2.5%-8.6%, 11.8%-39.1%, and 18.6%-20.0%, respectively. There was a statistically significant difference between benign tumours and encapsulated or widely invasive carcinomas, as in previous studies. A value of 10% was appropriate to distinguish benign from malignant lesions. PCNA-positive cells in indeterminate-type non-OCT were not significantly different from those in benign tumours, ranging from 4.3%-19.6%, and occurring at more than 10% in three of six tumours. Among OCT the positivity was less than 10% in benign tumours (4.5%-7.8%) and more than 10% in malignant tumours (14.1%-35.9%) and all the eight indeterminate tumours (12.5%-27.3%), with a statistically significant differences between the benign tumour and each of the latter types. These results indicate that the examination of PCNA is valuable in diagnosis of thyroid follicular tumours and that the use of similar diagnostic criteria may be warranted in both non-OCT and OCT.

Proliferating cell nuclear antigen (PCNA) immunostaining as an alternative to bromodeoxyuridine (BrdU) immunostaining for brain tumours in paraffin embedded sections.

Immunohistochemical staining for proliferating cell nuclear antigen (PCNA) and BrdU using anti-PCNA and anti-BrdU monoclonal antibodies, respectively, was performed in 16 human brain tumours, including 3 glioblastomas multiforme, 2 anaplastic astrocytomas, 1 cerebellar astrocytoma, 2 recurrent meningiomas, 4 non-recurrent meningiomas, 3 neurinomas and 1 medulloblastoma. Patients with brain tumours received an injection of bromodeoxyuridine (BrdU) intravenously during surgery, and tumour specimens were fixed in 70% ethanol and embedded in paraffin. The percentage of positive cells for PCNA was compared with a BrdU labelling index using adjacent paraffin-embedded sections. The percentage of PCNA-positive cells was correlated with the BrdU labelling index and the histological malignancy of the brain tumours. The correlation coefficient was 0.84. This suggests that the immunohistochemical staining for PCNA in paraffin sections is a good alternative to the BrdU labelling index.

Proliferating cell nuclear antigen (PCNA)/cyclin expression during the cell cycle in normal and leukemic cells

Bivariate flow cytometric analysis of the cell proliferation-associated nuclear protein, identified as the “proliferating cell nuclear antigen” (PCNA)/cyclin and of nuclear DNA content, was performed in quiescent and mitogen-stimulated human peripheral blood lymphocytes, in EUE (human embryonic epithelium) cells, before and after a long-term exposure to a hypertonic (HT) medium, in 4 human leukemic cell lines and in fresh bone marrow (BM) cells from 10 patients with untreated acute non-lymphoblastic leukemia (ANLL). The PCNA/cyclin was detected using both an autoantibody extracted from sera of systemic lupus erythematosus patients and the recently produced mouse monoclonal antibody (MoAb) IgG, named 19F4. The distribution of cells in the different phases of the cycle and the percentage of S-phase cells were obtained in duplicate samples, by DNA flow cytometry (FCM) and by dual parameter FCM of DNA content and bromodeoxyuridine (BUDR) incorporation. In all cell types, the non-specific cytoplasmic background fluorescence was significantly lower with the MoAb compared to that obtained with the polyclonal Ab. The percentage of PCNA-positive cells (both with the autoantibody and the 19F4 MoAb) was always higher than that of S-phase cells by DNA FCM and of BUDR-labeled cells. The pattern of PCNA-expression in both normal proliferating cells and acute leukemia cells, showed that most G 0/G 1 cells did not express significant amounts of PCNA; an increase in PCNA immunofluorescence was found in late G 1 cells, and further increases were observed in S- and G 2-M phase cells. PCNA/cyclin, as revealed both with autoantibodies and with the 19F4 MoAb, is associated with all actively or potentially dividing (i.e. G 1, S and G 2-M) cells thus identifying the proliferative cellular compartment. Combined with the use of multiparameter FCM techniques, the PCNA immunolocalization offers a useful tool to study cell kinetics in normal and leukemic human cell populations.