Proliferating cell nuclear antigen (PCNA) immunolocalization in paraffin sections: an index of cell proliferation with evidence of deregulated expression in some neoplasms

Methodological aspects of the immunostaining of proliferating cell nuclear antigen (PCNA) in cytospin preparations of MCF-7 cell line

Cytospins of a human breast cancer cell line (MCF-7) were studied for the expression of PCNA, a cell cycle-related protein, using a variety of fixation and immunostaining procedures. The best fixative for PCNA was found to be buffered formaldehyde solution at 4 degrees C followed by methanol at 20 degrees C, whereas alcoholic fixatives decreased greatly the PCNA immunoreactivity. Air-drying procedures of cytospins prior to and after fixation greatly undermined the PCNA immunostaining. A modified immunoperoxidase method provided a stronger staining of the PCNA-reactive cells than the alkaline phosphatase anti-alkaline phosphatase (APAAP) technique. PCNA immunoreactivity could be maintained up to 2 mo, putting slides in methanol at -20 degrees C. In conclusion, our report indicates that PCNA is a labile antigen, which may critically be affected by temperature and air-drying procedures.

Nuclear DNA content, proliferating-cell nuclear antigen (PCNA) and p53 immunostaining in predicting progression of laryngeal cancer in situ lesions

Squamous epithelial cancer in situ (CIS) of the upper aerodigastric tract is a histopathologically well-defined condition. However, in clinical practice, morphological grading of dysplasia is difficult and shows large variability. The biology of CIS remains enigmatic, and there is yet no reliable way to predict whether a CIS lesion will progress to invasive cancer, remain stable or regress. In the search for markers able to foretell clinical outcome, we performed image DNA cytometry (ICM) and immunohistochemical staining for PCNA as well as p53 in 38 laryngeal CIS lesions, of which 9 progressed to invasive cancer. The majority of the CIS lesions displayed high-grade DNA aberration, a high PCNA-positive rate, and every third lesion was p53-positive by immunostaining. The lesions which progressed to invasive cancer showed a clear tendency towards more pronounced DNA aberration, a higher percentage of intense PCNA staining and more frequent p53 positivity. By combining the results from the analyses of DNA, PCNA and p53 in a prognostic index for each individual case, we correctly classified 82% of the lesions as progressors or non-progressors.

Tubular atrophy in the end-stage kidney: a lectin and immunohistochemical study

Atrophic tubules in end-stage renal disease (ESRD) may have various morphologic appearances: some show microscopic features of "classic" atrophic tubules (thick, wrinkled tubular basement membrane and simplified epithelium), others show "thyroidization" (round tubules with simplified epithelium and casts), and many have the appearance of "endocrine" tubules (small tubules with narrow lumina, clear cells, and relatively thin basement membranes). Other tubules in ESRD may be enlarged and dilated with hypertrophic cells ("super" tubules). The exact segment of the nephron from which these tubules arise in ESRD has not been well studied. We examined paraffin sections of 28 end-stage kidneys with a panel of nephron-segment-specific renal epithelial markers (proximal nephron markers: Tetragonolobus purpureas and Phaseolus vulgaris erythroagglutinin lectins; distal nephron markers: antibodies to epithelial membrane antigen, low molecular weight cytokeratin [AE1/AE3], the lectin Arachis hypogaea, and an antibody to Tamm-Horsfall protein labeling the thick ascending limb of Henle). In addition, an antibody to proliferating cell nuclear antigen was applied to determine the proliferation index (proliferating cell nuclear antigen-positive nuclei/all counted nuclei x 100, ie, the percentage of proliferating cell nuclear antigen-positive nuclei) of the various atrophic and "super" tubules in ESRD. Classic atrophic tubules and the "super" tubules showed primarily a proximal phenotype. Tubules showing thyroidization were consistently positive with markers of the distal tubular epithelium. "Endocrine" tubules stained primarily with distal tubular markers; however, some proximal staining also was noted. The widened renal interstitium contained single cells or loosely organized small cell clusters positive with both the AE1/AE3 and the epithelial membrane antigen antibodies. Serial sectioning showed that the majority of these single cells were not forming tubules. The proliferation index of the "classic" atrophic tubules was the highest (3.08%), followed by the "super" tubules (2.39%), the "endocrine" tubules (1.58%), and the "thyroid" tubules (1.09%). These indexes are all considerably higher than the proliferation index of the normal renal tubular epithelium. Our findings suggest that different types of tubular atrophy may arise from different segments of the nephron, and that the renal interstitium in ESRD may harbor isolated cells with epithelial characteristics. Furthermore, the end-stage kidney is not a resting organ; on the contrary, it shows a high proliferative activity, particularly in the epithelium of the "classic" atrophic and the "super" tubules.

PC-10 immunostaining of proliferating cell nuclear antigen in posterior uveal melanoma. Enucleation versus enucleation postirradiation groups

PURPOSE

It is difficult to assess the viability of uveal melanoma after radiotherapy treatment. The purpose of the current study is to investigate PC-10 monoclonal antibody of proliferating cell nuclear antigen as a possible marker for cell proliferation and tumor viability in conventionally processed histologic preparations of uveal melanoma irradiated by brachytherapy as well as in nonirradiated melanomas.

METHODS

Thirteen enucleated eyes with posterior uveal melanoma that were treated by brachytherapy (cobalt 60 or ruthenium 106 radioactive plaques) were included in this study. Thirteen enucleated eyes of the same size with nonirradiated posterior uveal melanoma served as controls. The tumors were stained with PC-10 monoclonal antibody to proliferating cell nuclear antigen. All clinical and histologic data of the tumors were recorded and analyzed.

RESULTS

Five of the irradiated tumors showed positive staining with PC-10, although with a low score. Four of these tumors showed regrowth, and the fifth tumor was treated with a low-irradiation dose (5500 rad). In the nonirradiated tumor group, nine were positive for PC-10 staining, with a higher score. Significant correlation was found in this group between the PC-10 score and the mitotic figure count, but not with other prognostic factors. In three of four tumors that caused metastatic death, the PC-10 staining was positive and had a high score.

CONCLUSIONS

PC-10 immunostaining is a simple, reproducible method that can be applicable to conventionally processed histologic preparations. It clearly shows that cellular proliferation activity in nonirradiated and irradiated uveal melanomas. Based on the small number of cases reported herein, it seems that the PC-10 score can correlate with prognosis, but further studies should be performed.

Comparative flow cytometric analysis of proliferating cell nuclear antigen (PCNA) antibodies in human solid neoplasms

Proliferating cell nuclear antigen (PCNA), an auxiliary protein of DNA polymerase delta, associated with DNA synthesis, is increasingly used to determine tumor growth rate. To determine the growth fraction by PCNA, various antibodies and fixation procedures are being used. We assessed the flow-cytometric measurement of PCNA using three monoclonal antibodies (PC10, 19F4, and 19A2) and two fixation protocols (paraformaldehyde and methanol) in tissue-culture cell lines and human solid neoplasms to determine their potential clinical application. Thirty-one solid tumors and four normal tissues were analyzed, along with MOLT-4 and HL-60 cell lines as positive controls and normal peripheral blood lymphocytes as a negative control. PC10 with methanol fixation consistently detected higher PCNA positivity in human solid neoplasms than 19F4 and 19A2. Using PC10, the differences in positivity among fixation methods occurred in the G0/1 phase, not in S + G2M, of the cell cycle. No correlation was found between PCNA positivity and tumor grade and DNA ploidy in tumors analyzed. A statistical correlation was found between overall PCNA positivity and RNA content as determined by acridine orange analysis. The growth fraction by PCNA in solid neoplasms was most reliably determined by PC10 with methanol fixation.

Comparison of cytophotometric characteristics to histology and proliferation markers in acoustic neuromas

Specimens of histologically confirmed acoustic neuromas obtained during operation in 25 patients were examined. Quantitative DNA measurements were performed with an image analysis system. From the single cell measurements, the mean DNA content of all tumor cells, 2c deviation index (2c DI), DNA entropy, DNA grade of neoplasia, and percentage of tumor cells with a DNA content of more than 5c (5c exceeding rate) were derived, as well as the mean nuclear area of the tumor cells. Proliferating cell nuclear antigen (PCNA) was identified immunohistochemically. A PCNA score was developed in determining PCNA-positive cells in a total amount of 1,000 cells. Results of quantitative DNA measurements and PCNA scores were compared to clinical symptoms, histology, and time between first onset of symptoms and diagnosis of the tumor. Quantitative DNA measurements revealed the existence of hyperdiploid tumor cells in all neuromas. According to the frequency with which they occurred, tumors could be divided into two categories: 1) tumors with a high percentage of hyperdiploid cells ("hyperdiploid tumors") and 2) those with a low percentage ("diploid tumors"). Hyperdiploid tumors showed increased values for the 2c DI, mean DNA content, DNA grade of neoplasia, and DNA entropy as signs of increased proliferation. In addition, the PCNA scores were higher in these tumors, indicative of increased DNA synthesis. The mean nuclear area was higher in these tumors. No correlation was found between the results of the DNA analysis and the PCNA score, or the clinical data and the predominant histologic subtype.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunohistochemical study on proliferating cell nuclear antigen expression in ameloblastomas

The aim of this study is to evaluate the proliferating activity of ameloblastomas and its correlation to the biological behaviour according to each histological type. 38 cases of solid and unicystic ameloblastomas were reviewed including 1 case of ameloblastic carcinoma and 1 recurrent case. An anti-PCNA antibody, PC10(Dako), was applied for the detection of proliferating cell nuclear antigen (PCNA) in paraffin embedded tissue sections. Also 20 cases of dentigerous cysts were reviewed. In conclusion, we observed that there was no difference between the proliferating activities of the different histological types of solid ameloblastomas. Because 1 case of ameloblastic carcinoma and one recurrent case revealed remarkably high PCNA reactivity, we believe that PCNA would be useful in showing the differentiation between benign and malignant ameloblastomas. In unicystic ameloblastomas, plexiform intraluminal growth was considered to be an important feature in tumorous transformation of cystic epithelium.

p53, c-myc p62 and proliferating cell nuclear antigen (PCNA) expression in non-Hodgkin's lymphomas

AIMS

To investigate the immunohistochemical expression of p53 protein in non-Hodgkin's lymphomas (NHL) and its relation to that of c-myc p62 oncoprotein and proliferating cell nuclear antigen (PCNA).

METHODS

Paraffin wax embedded tissue from 90 non-Hodgkin's lymphomas (72 B cell and 18 T cell) was stained immunohistochemically for p53 protein, c-myc p62 oncoprotein, and PCNA using the monoclonal antibodies DO7, c-myc 1-9 E10, and PC-10, respectively.

RESULTS

Of the non-Hodgkin's lymphomas studied, 55 (61%) stained positively for p53 protein. The proportion of positive cases increased from low grade non-Hodgkin's lymphoma and was higher in tumours of T cell origin. The percentage of positive cells (labelling index or LI) was significantly lower in low grade non-Hodgkin's lymphoma, but no difference was established between intermediate and high grade non-Hodgkin's lymphoma. In a large proportion of low grade non-Hodgkin's lymphoma the LI was below 1%. c-myc p62 immunoreactivity was identified in all cases. A significant positive correlation was established between p53 LI and c-myc p62 LI (rs = 0.453) as well as between p53 LI and PCNA LI (rs = 0.338).

CONCLUSIONS

p53 immunoreactivity was present in about half the cases of non-Hodgkin's lymphoma and was related to the grade of malignancy and possibly to the B or T cell origin of the tumour. It was also associated with the proliferation state as expressed by PCNA LI and c-myc p62 expression, indicating that the expression of these three cell cycle-related genes might be interrelated.

MIB-1, Ki67, and PCNA scores and DNA flow cytometry in intermediate grade malignant lymphomas

AIMS

To verify the correlation between MIB-1, Ki67, and proliferating cell nuclear antigen (PCNA-PC10) scores and S-phase fraction in intermediate grade non-Hodgkin's lymphomas (Working Formulation F); and their reliability in differently processed tissues.

METHODS

Forty one non-Hodgkin's lymphomas were classified as (F) intermediate grade malignant lymphomas according to the Working Formulation; mitotic counts and percentage of large cells were assessed for each case. Sections from formalin fixed, paraffin wax embedded tissues were stained with anti MIB-1 monoclonal antibody, after microwave oven processing, and anti-PCNA (PC10) monoclonal antibody using an avidin-biotin immunoperoxidase (ABC) method. One thousand cells from 10 representative fields were scored. Frozen sections from surgical specimens were stained with Ki67 monoclonal antibody using the ABC method; the fraction of Ki67 positive cells was calculated scoring 1000 cells. Flow cytometry analysis (FCM) was performed on cell suspensions from fresh tissues. Correlations between data were estimated using linear regression.

RESULTS

A linear correlation was found between MIB-1 and Ki67 scores (r = 0.92; p < 0.00001); between MIB-1 and PCNA scores (r = 0.79; p < 0.00001); and between MIB-1 score and S-phase fraction (r = 0.51; p = 0.0006). A linear correlation was also found between Ki67 and PCNA scores (r = 0.85; p < 0.00001); between Ki67 score and S-phase fraction (r = 0.6; p = 0.0002); and between PCNA score and S-phase fraction (r = 0.74; p < 0.00001). A correlation was found between mitotic counts and MIB-1 (r = 0.56; p = 0.0001), PCNA (r = 0.51; p = 0.0007), or Ki67 scores (r = 0.47; p = 0.002); between the percentage of large cells and MIB-1 (r = 0.49; p = 0.0009), PCNA (r = 0.6; p = 0.00003), and Ki67 scores (r = 0.53; p = 0.0003) and S-phase fraction (r = 0.55; p = 0.0002).

CONCLUSION

MIB-1, Ki67, and PCNA (PC10) scores and S-phase fraction are highly correlated and equally well represent the proliferative activity of intermediate grade non-Hodgkin's lymphomas in differently processed material. MIB-1 and PCNA stains can be applied even on small biopsy specimens. MIB-1 produces homogenous staining without background; it also strongly stains mitotic figures. It can be performed on routinely processed tissues, permitting the simultaneous evaluation of the morphology and tumour cell kinetics. The wide standard deviations of the proliferative indices found for intermediate grade NHL suggest that this category probably includes various degrees of malignancy.

Proliferating cell nuclear antigen (PCNA) expression of megakaryocytopoiesis in normal human bone marrow and reactive lesions with special emphasis on HIV-myelopathy

A morphometric analysis was performed on bone marrow trephine biopsies using sequential double-immunostaining, to evaluate endoreduplicative activity of megakaryocytopoiesis. A total of 104 marrow specimens were studied with employment of monoclonal antibodies PC10 (anti-proliferating cell nuclear antigen-PCNA) and Y2/51-CD61 (anti-platelet glycoprotein IIIa). In addition to the control group patients included non-specific inflammatory changes, HIV-myelopathy with normal or decreased platelet counts, idiopathic thrombocytopenic purpura (ITP), and finally reactive thrombocytosis (TH). To exclude an undue overexpression of PCNA, in a comparative pilot study we also applied MIB1 (Ki-67 antigen) on normal bone marrow specimens. In accordance with the various modalities of cell-cycle marker expression, no significantly different findings were disclosed. PCNA-labelling index was relatively low, ranging from 0.8 to 1.7% of the total megakaryocytopoiesis (promegakaryoblasts to mature platelet-shedding megakaryocytes). A significant relationship between megakaryocyte size and PCNA-expression was determinable. This implies that some of the cases with a prevalence of small megakaryocytes, like ITP, have the tendency to show a higher proportion of positively-stained cells. Moreover, this feature confirms a hypothesis postulating a decrease in the time for DNA-synthesis (S-phase) and a relative prolongation of the G1/G2-phases of the cell-cycle at higher ploidy levels (large-sized megakaryocytes). On the other hand, it may be speculated that some of the hyperpolyploid giant megakaryocytes may have reached their endstage of endoreduplication and enter into G0-phase. In comparison with the control group and the other entities under study, a significant reduction of PCNA-reactivity was recognizable in HIV-myelopathy accompanied by thrombocytopenia.(ABSTRACT TRUNCATED AT 250 WORDS)

The pathobiology of salivary gland. III. PCNA-localization of cycling cells induced in rat submandibular gland by low-dose x-radiation

Application of ionizing radiation to adult rat major salivary glands tested tenets of the bicellular reserve cell hypothesis for the induction of salivary gland tumors, namely, that stem cells preferentially located to luminal cells of the intercalated duct and basal cells of the excretory duct in normal salivary glands. The effect of a single, low dose (3000 cGy) of x-radiation administered to the parotid and submandibular glands was followed with the use of immunocytochemistry and an antibody to the cell cycle-related protein proliferating cell nuclear antigen to detect the kinetics and localization of cycling cells up to 15 days postirradiation. Maximal responses occurred in acinar cells (12.6-fold increase) of submandibular glands on day 7 postirradiation. Similar but less dramatic concurrent increases in proliferating cells were evident in intercalated (3.4-fold) and striated (2.2-fold) duct cells, but little response was seen in basal or luminal cells of submandibular gland excretory ducts. A limited but maximal proliferative response again occurred on day 7 in the parotid gland. Neither in the steady state nor irradiated submandibular gland was there evidence of specific stem ("reserve") cells associated with the intercalated or excretory ducts. It appears unnecessary to invoke stem cells in a model of cellular proliferation in salivary glands. Therefore current concepts of salivary gland tumorigenesis require modification because all cell types, including acinar cells, are at risk in the carcinogenic process.

Comparison of different monoclonal antibodies for the immunohistochemical assessment of cell proliferation in routine colorectal biopsy specimens

In a series of paraffin-embedded colorectal biopsy specimens the monoclonal antibodies 19F4 and PC10 against the proliferating cell nuclear antigen (PCNA) and the antibody mib1, which recognizes the Ki67 antigen in formalin-fixed material, were compared with the Ki67 method on equivalent frozen sections to assess the applicability of these 'proliferation markers'. A high correspondence was found between the localization of the mib1 and the Ki67 immunoreaction product, associated with a highly significant quantitative correlation of the two indices (r = 0.70, p < 0.001). In contrast, after formalin fixation the two PCNA antibodies additionally stained cells outside the proliferative compartment so that a reliable assessment of cell proliferation was only possible after controlled paraformaldehyde or methacarn fixation. In the routine material mib1 was superior to PC10 because of its ability to distinguish the differences in cell proliferation among normal colorectal mucosa (29.1 +/- 6.8% positive cells), adenomas (43.3 +/- 10.6%), and carcinomas (52.9 +/- 8.7%), which PC10 did not possess (normal, 41.4 +/- 5.6%; adenomas, 37.5 +/- 8.7%; carcinomas, 51.5 +/- 8.2%).

Inhibitory effects of magnesium hydroxide on c-myc expression and cell proliferation induced by methylazoxymethanol acetate in rat colon

The effects of magnesium hydroxide were examined on methylazoxymethanol (MAM) acetate-induced c-myc expression and cell proliferation of colonic mucosal epithelium in rats. Rats were divided into four groups and treated as follows: MAM acetate alone (25 mg/kg i.p. injection, five times, once a week for 5 weeks), MAM acetate and feeding of 0.2% magnesium hydroxide in diet, magnesium hydroxide alone and non-treatment. At 4, 8 and 16 weeks after the start of experiment, 10 rats in each group were sacrificed. Magnesium hydroxide inhibited the MAM-induced expression of c-myc proto-oncogene, and also suppressed the increased bromodeoxyuridine (BrdU) and proliferating cell nuclear antigen (PCNA) labelling indexes induced by MAM acetate in colon mucosa in initiation and post-initiation phase. These results suggest that the anti-carcinogenic effect of magnesium hydroxide on rat colon carcinogenesis induced by MAM acetate may be related to the inhibition of the carcinogen-induced expression of c-myc proto-oncogene and cell proliferation.

Keratin expression reveals mosaic differentiation in vaginal epithelium

OBJECTIVE

Analyzing the expression of keratins has proved to be valuable for identifying of pathways of epithelial differentiation. In stratified epithelia K10 and K13 are representative for either the keratinizing (epidermal-type) or the nonkeratinizing pathway.

STUDY DESIGN

We have investigated keratin expression in "normal" vaginal epithelium from 30 women, applying two-color immunofluorescence with monoclonal antibodies to K10 and K13 on cryostat sections and cell smears.

RESULTS

A differential expression pattern of vaginal cells dependent on their localization within the epithelium was found. In cells of the first suprabasal layers differentiation began and became identifiable by a weak expression of K13. The adjacent layers displayed cells that concurrently expressed K10 and K13. In contrast, cells within the superficial strata expressed exclusively either one of the two keratins.

CONCLUSION

Thus vaginal epithelium appears to be mosaic in differentiation, showing simultaneous expression of keratins K10 and K13, thought to be representative for distinct routes of differentiation.

Comparative analysis of p53 and c-myc expression and cell proliferation in human hepatocellular carcinomas--an enhanced immunohistochemical approach

Expression of p53 and c-myc was investigated and compared with cell proliferative activity in a series of 40 hepatocellular carcinomas (HCC), by means of enhanced immunohistochemistry. p53 expression was demonstrated in 5 out of 40 HCC (12.5%) with the incidence increasing in 5 out of 40 HCC (12.5%) with the incidence increasing in proportion to the histological grading of malignancy: thus, 0% of well-differentiated, 6.9% of moderately differentiated and 33.3% of poorly differentiated lesions were positive. The proliferating-cell nuclear antigen (PCNA) labeling index also showed a statistically significant increase with this grading. Distribution patterns of PCNA-positive cell were divided into four types: scatter, marginal, mosaic and diffuse. Four HCC cases, predominantly of the poorly differentiated type, exhibited the diffuse pattern. Generally, p53 overexpression corresponded well with PCNA positivity. In contrast, there was no correlation between c-myc overexpression, found in 19 out of 40 HCC (47.5%), and histological grading of HCC or PCNA labeling index. The distribution pattern of c-myc-positive HCC cells was also different from that of PCNA and p53. Our results suggest that p53 overexpression closely relates to proliferation of HCC cells. Furthermore, there may be a consistent difference in regulatory mechanisms between p53 and c-myc expression in multistep hepatocarcinogenesis.

p53 expression in oat and non-oat small cell lung carcinomas: correlations with proliferating cell nuclear antigen

AIMS

To investigate the immunohistochemical expression of p53 protein in small cell lung carcinoma (SCLC), comparing it with that in non-small cell carcinoma (NSCLC); and to evaluate the correlation between p53 and proliferating cell nuclear antigen (PCNA) expression as well as between p53 and PCNA expression and survival.

METHODS

Paraffin wax embedded tissues from 61 cases of primary lung carcinoma were stained for p53 protein and PCNA using the monoclonal antibodies 1801 and PC-10, respectively, in a standard avidin-biotin immunoperoxidase method.

RESULTS

Of the 61 lung carcinomas 35 (57%) were positive for p53 (range 1% to 90%). Ninety percent of the non-oat SCLC contained positive cells and the labelling index (LI) was significantly higher than that of the oat SCLC (p < 0.001). SLCC also displayed a higher p53 LI than NSCLC (p < 0.01); no difference was found between squamous carcinoma, adenocarcinoma, and oat cell carcinoma. A p53 LI of greater than 1% tended to be associated with nodal metastases (p < 0.05), and p53 expression in node positive tumours as well as in oat cell carcinomas was indicative of poorer survival (p < 0.01 and p < 0.1, respectively). A p53 Li of greater than 60% was a negative prognostic factor in non-oat SCLC (p < 0.05). PCNA LI was highest in non-oat SCLC and lowest in NSCLC; oat cell carcinomas had a mean LI intermediate between NSCLC and non-oat SCLC (NSCLC v oat cell carcinoma p < 0.05 and oat cell v non-oat cell carcinomas p < 0.01). A PCNA LI was not correlated with nodal metastases or survival, but there was a significant positive correlation between PCNA LI and p53 LI (rs = 0.484, p < 0.001).

CONCLUSIONS

p53 and PCNA expression differ substantially among the various types of lung carcinomas. Substantial differences were also found between oat and non-oat types of SCLC, indicating that SCLC is heterogeneous as far as proliferation rate and altered p53 expression is concerned. p53 seems to be of some prognostic value. The relation between PCNA and p53 expression indicates that the PCNA gene is slightly upregulated by p53.

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.

Splenic haematopoiesis in primary (idiopathic) osteomyelofibrosis: immunohistochemical and morphometric evaluation of proliferative activity of erytro- 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 immunohistochemical 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.

Immunohistochemical comparison between anaplastic seminoma and typical seminoma

In order to study the possible biological differences between anaplastic and typical seminoma, the following factors were studied in 11 cases of anaplastic seminoma and 15 cases of typical seminoma: mitotic activity, proliferating cell nuclear antigen (PCNA) expression, immunohistochemical analyses for cytokeratin, vimentin, placental alkaline phosphatase (PLAP), beta-human chorionic gonadotropin (beta-hCG), alpha-fetoprotein (AFP) and c-myc oncoprotein. Anaplastic seminoma was classified according to Mostofi's criteria, which is primarily based on the mitotic activity of the tumor. Mitotic activity was evaluated by both mitotic count and rate. Statistically significant correlations were observed between mitotic count and mitotic rate (R = 0.891), and between the mitotic count and PCNA labeling index (R = 0.792), in both typical and anaplastic seminomas. Immunostaining patterns for cytokeratin, vimentin, PLAP, beta-hCG, AFP and c-myc oncoprotein were not significantly different between typical and anaplastic seminoma. The present data indicated that no apparent clinicopathologic and immunohistochemical parameters discerning anaplastic seminoma from typical seminoma were present, when identifying anaplastic seminoma on the basis of high mitotic count. Anaplastic seminoma may therefore simply represent seminoma with high proliferative activity.

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.(ABSTRACT TRUNCATED AT 250 WORDS)

Proliferating cell nuclear antigen in hepatocellular carcinoma and small cell liver dysplasia

BACKGROUND

Recently, proliferating cell nuclear antigen (PCNA) has been measured by using a monoclonal antibody in a variety of malignant neoplasms.

METHODS

The authors evaluated cell proliferative activity by immunostaining for PCNA in 92 hepatocellular carcinoma nodules and 14 lesions of small cell liver dysplasia.

RESULTS

The average PCNA labeling indices (LI) in Grades I, II, III, and IV were 12.2%, 17.5%, 53.7%, and 83.9%, respectively. There were statistically significant differences in the PCNA LI between all the histologic grades, except for Grades I and II. The less differentiated the histologic grade, the higher the PCNA LI became. This finding was also recognized in a hepatocellular carcinoma showing a "nodule in a nodule" appearance, in which the less-differentiated inner nodule had a higher PCNA LI than did the well-differentiated outer lesion. For an analysis of the disease-free survival in 74 patients with clinical follow-up data, 2 groups of patients with a PCNA LI higher and lower than the average level (32.0%) were compared. The disease-free survival rate after surgery was significantly higher (P < 0.005), and the venous invasion was significantly less frequent (P = 0.0003) in the low PCNA LI group than in the high PCNA LI group. The average PCNA LI in small cell liver dysplasia was 13.9%, which was almost equal to that of Grades I and II hepatocellular carcinoma.

CONCLUSIONS

The PCNA LI of hepatocellular carcinoma showed a close correlation with both the histologic findings and the biologic behavior. Small cell liver dysplasia was a small round focus having proliferative activity similar to that of Grades I and II hepatocellular carcinoma.

The relationship between proliferative and oxygenation status in spontaneous canine tumors

PURPOSE

Immunocytochemical markers have been applied to biopsy specimens from spontaneous canine tumors to assess the prevalence and spatial distribution of proliferating and hypoxic cells, and their "geographic" relationship to each other. Both types of cells have been implicated in the failure to locally control human tumors treated with radiation and chemotherapy.

METHODS AND MATERIALS

For the detection of hypoxic cells, a rabbit polyclonal antibody raised against a protein-bound, hexafluorinated, 2-nitroimidazole, designated CCI-103F, was used. The unmetabolized drug must first be injected into the dog to allow time for hypoxic metabolism and cellular binding to occur. For the detection of proliferating cells, a mouse monoclonal antibody raised against an endogenous nuclear protein, the "proliferating cell nuclear antigen," or PCNA, was used. This protein is expressed in most actively proliferating cells, but not in quiescent ones. An indirect immunostaining technique was used to visualize these markers in the tissue sections, and image analysis was used to estimate the area fraction of positive staining in representative, low magnification microscope fields.

RESULTS

Tumors with both high and low hypoxic and proliferative area fractions have been identified. No systematic relationship between the prevalence of the two markers, nor of the relationship between tumor grade and proliferative fraction, could be established. Staining with the proliferation marker was more commonly found near blood vessels, but some "nests" of tumor cells apparently distant from vasculature contained many proliferating cells. Staining with the hypoxia marker tended to be distant from the vasculature and/or bordering regions of tumor necrosis, but some labeled cells appeared near blood vessels, and in the absence of necrosis. Staining of sequential sections, one with the proliferation marker and one with the hypoxia marker, indicated that the two cell populations overlapped to varying extents. Some incidental staining of canine normal tissues with both the proliferative and hypoxia markers was observed as well.

CONCLUSION

The immunochemical marker approach promises to be a useful tool to increase both our basic understanding of tumor physiology and the complex nature of tumor heterogeneity.

Proliferation kinetics and PCNA expression of HL-60 cells following ionizing irradiation and granulocytic differentiation

The human promyelocytic leukaemia cell line, HL-60, was investigated with regard to proliferation and terminal differentiation following irradiation. The cells were X-irradiated and induced with 1.25% dimethyl sulfoxide (DMSO) towards the granulocytic lineage. Proliferation was measured via cell growth, clonogenicity and the bromodeoxyuridine/DNA incorporation assay. Immunohistochemical detection of proliferating cell nuclear antigen (PCNA) expression was used to discriminate cycling from non-cycling cells. The differentiation obtained was proved by testing for the immune function of the respiratory burst (NBT reduction test). The HL-60 cells studied revealed a high radiosensitivity (D0 = 0.63 Gy). After induction with DMSO, declines in cell growth, clonogenicity and PCNA positivity of the cells indicated a decrease in proliferation and an increase in differentiation. Starting on day 2 in culture, irradiation after seeding with 1 Gy accelerated the loss of the PCNA expression in induced cells (46% v. 3% PCNA-negative control cells on day 3). Induced cells gained the capability of exerting the respiratory burst, which was found to be dose-dependent radiosensitive (42%, and 12% NBT-positive cells after 1 and 2 Gy, respectively, v. 53% NBT-positive control cells on day 8). Subpopulations in the cell line were evident in all parameters investigated. We discuss the HL-60 cell, not only as a model comparable to human progenitor cells, but also as a suitable tool in radiobiological research with regard to proliferation and differentiation following ionizing irradiation.

Comparison of isotopic and immunohistochemical methods of studying epithelial cell proliferation in hamster tongue

Our purpose was to validate different approaches to the study of cell proliferation in stratified squamous epithelia, using oral mucosa as a model. Dorsal and ventral tongue from the hamster were examined following in vivo labelling with tritiated thymidine and bromodeoxyuridine (BrdUrd), and in vitro labelling with BrdUrd. These were compared with direct immunolabelling of fixed tissue sections with monoclonal antibody PC10. For the former methods S phase cells were quantified following autoradiography or immunohistochemistry. We conclude that the proliferative status of simple, flat, lining mucosae such as ventral tongue can be derived by all three pre-labelling methods and, on average, 18-19 cells per surface millimetre length were in DNA synthesis. On the other hand dorsal tongue epithelium, which is thicker, has an undulating morphology and a complex cell renewal pattern, gives different results with the three labelling methods. In both sites the proliferating cell nuclear antigen (PCNA) index was fourfold that obtained by nucleotide labelling. This is consistent with PCNA marking proliferative cells in other phases of the cell cycle in addition to the S phase. Thus, there are potential differences between the information on proliferative status derived by PCNA immunohistochemistry and other established cell cycle markers, which need to be taken into account in the interpretation of epithelial cell kinetic data in health and disease.

Exogenous epidermal growth factor fails to accelerate functional recovery in the autotransplanted ischemic pig kidney

The reversibility of ischemic renal injury is dependent on epithelial cell regeneration and repopulation of the nephron. Renal cells produce and respond to many growth factors. In the rat, epidermal growth factor (EGF) is mitogenic for tubular cells and accelerates renal recovery after ischemia. We used a pig renal autotransplant model to evaluate the effect of exogenous EGF on renal recovery in a large animal more analogous to man. Group 1 animals underwent left autotransplant after 120 minutes of warm ischemia and received either a single intra-arterial dose of recombinant human EGF (EGF, 10(-7) M.) (N = 11) or vehicle alone (N = 6). Group 2 animals underwent left autotransplant after 72 hours of cold preservation with Collins' solution and received a similar intra-arterial dose plus a subcutaneous dose of EGF (0.5 ml. of 10(-3) M.) (N = 8) or vehicle alone (N = 6). Contralateral nephrectomy was performed in all animals. Daily creatinine measurements revealed no beneficial effect from EGF on recovery of renal function in Group 1 or 2 animals. Studies of EGF on pig proximal tubular cells demonstrated in vitro mitogenesis; autoradiography with 125I-EGF revealed binding of EGF throughout the kidney. Immunohistochemistry showed significant tubular cell proliferation in response to ischemic injury, without further enhancement from EGF. Thus, although exogenous EGF bound to pig kidney cells and stimulated cell proliferation, we were unable to demonstrate a clinically significant acceleration of recovery from ischemic injury.

Proliferative activity of gastric cancer assessed by immunostaining for proliferating cell nuclear antigen

The growth activity of 107 gastric carcinomas was assessed by immunohistochemical staining for formalin-fixed, paraffin-embedded tissue with a monoclonal antibody against proliferating cell nuclear antigen (PCNA). When the tumor doubling times (Tds) of 10 patients were estimated from the serum levels of carcinoembryonic antigen and carbohydrate antigen 19-9, there was an inverse correlation between the Tds and PCNA labeling index (LI) at P = 0.055. Flow-cytometric analysis was carried out by double staining for PCNA and DNA using fresh materials from 14 patients. The PCNA-positive cell fraction revealed by flow cytometry showed a good linear correlation with PCNA LI in routinely stained tissue. The LI of well-differentiated adenocarcinoma was significantly higher than that of the poorly differentiated type. When the LI was analyzed in well- or poorly differentiated adenocarcinoma, the value was significantly higher in the well-differentiated type with hepatic metastasis and in the poorly differentiated type with lymph node metastasis.

The cell proliferation-associated antigen of antibody Ki-67: a very large, ubiquitous nuclear protein with numerous repeated elements, representing a new kind of cell cycle-maintaining proteins

The antigen defined by mAb Ki-67 is a human nuclear protein the expression of which is strictly associated with cell proliferation and which is widely used in routine pathology as a "proliferation marker" to measure the growth fraction of cells in human tumors. Ki-67 detects a double band with apparent molecular weights of 395 and 345 kD in immunoblots of proteins from proliferating cells. We cloned and sequenced the full length cDNA, identified two differentially spliced isoforms of mRNA with open reading frames of 9,768 and 8,688 bp encoding for this cell proliferation-associated protein with calculated molecular weights of 358,761 D and 319,508 D, respectively. New mAbs against a bacterially expressed part and a synthetic polypeptide deduced from the isolated cDNA react with the native Ki-67 antigen, thus providing a circle of evidence that we have cloned the authentic Ki-67 antigen cDNA. The central part of the Ki-67 antigen cDNA contains a large 6,845-bp exon with 16 tandemly repeated 366-bp elements, the "Ki-67 repeats", each including a highly conserved new motif of 66 bp, the "Ki-67 motif", which encodes for the epitope detected by Ki-67. Computer analysis of the nucleic acid and the deduced amino acid sequence of the Ki-67 antigen confirmed that the cDNA encodes for a nuclear and short-lived protein without any significant homology to known sequences. Ki-67 antigen-specific antisense oligonucleotides inhibit the proliferation of IM-9 cell line cells, indicating that the Ki-67 antigen may be an absolute requirement for maintaining cell proliferation. We conclude that the Ki-67 antigen defines a new category of cell cycle-associated nuclear nonhistone proteins.

Flow cytometric analysis of the expression of PCNA during the cell cycle in HeLa cells and effects of the inhibition of DNA synthesis on it

Flow cytometric bivariate DNA/PCNA analysis was performed to investigate the expression of PCNA during the cell cycle and the implication in DNA replication in HeLa cells, using a monoclonal antibody (PC10) to PCNA. The expression of PCNA was evident in almost all cells growing exponentially, when cells were fixed in methanol. The total amount of PCNA altered a little during the cell cycle. However, the treatment with Triton X-100 extracted 80-89% of total PCNA from the cells, resulting in the dramatic change of bivariate DNA/PCNA distribution pattern. PCNA was completely removed from nuclei in both G1 and G2 phases by the detergent treatment, whereas a certain amount of PCNA remained in S phase nuclei. After the treatment of cells with Triton X-100, PCNA was detected exclusively in S phase cells. The bivariate DNA/PCNA distribution pattern in cells treated with Triton X-100 was strikingly so similar to the DNA/BrdUrd distribution pattern that it was unable to differentiate one from the other. It is concluded that the detergent treatment of cells allows the rapid analysis of the cell cycle. The inhibition of DNA synthesis with 10 mM hydroxyurea elevated cellular PCNA content mainly due to the increase in the fraction of the detergent extractable PCNA. It was apparent, however, that in cells incubated with Triton X-100, the pattern of the bivariate DNA/PCNA distribution was not basically different from that in cells without HU treatment. The level of PCNA bound to nuclear structures (PCNA not extracted with detergent) increased in cells arrested at the G1/S boundary with the time of hydroxyurea treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Transient increases of growth fraction during fractionated radiation therapy for cervical carcinoma. Ki-67 and PC10 immunostaining

BACKGROUND

The Ki-67 and PC10 indexes are consistent with the growth and S-phase fractions, respectively.

METHODS

Eighty-three biopsy specimens from 18 patients with cervical squamous cell carcinoma were examined before and during fractionated radiation therapy (RT), using an immunohistochemical method.

RESULTS

The 18 patients were divided into two groups according to the Ki-67 index before RT; those with values of less than 42% (Group A; n = 11) and those with values of 42% or more (Group B; n = 7). The Ki-67 index in Group A increased approximately twofold at radiation doses of 5.4-9 Gy compared with values before RT. The Ki-67 index in Group B, which increased slightly at doses of 5.4-9 Gy, decreased by approximately one-fifth at a dose of 27 Gy, compared with the value before RT. The PC10 indexes in both groups showed little change to doses of 5.4-9 Gy. The mitotic indexes were less than 1% before RT and decreased to a minimum with doses of 18-27 Gy. There was no correlation between the Ki-67 and PC10 indexes before or during RT.

CONCLUSION

In cancer tissues with a low growth fraction before RT, radiation doses of 5.4-9 Gy produced increases in the numbers of cycling cancer cells in the G1 or G2 phases. This transient increase possibly was attributable to the combined effects of the recruitment phenomenon and G1 or G2 block.

Nucleolar organizer regions (NORs) staining and proliferating cell nuclear antigen (PCNA) immunostaining in mucosa-associated lymphoid tissue (MALT) gastric lymphomas

Nucleolar organizer region-associated proteins (AgNOR) and proliferating cell nuclear antigen (PCNA) have been studied by means of a silver staining technique and immunohistochemistry, in paraffin-embedded, gastrectomy specimens of 12 low-grade and 13 high-grade gastric MALT lymphomas respectively. A significant difference was found between the AgNOR count and PCNA index of low-grade lymphomas (mean AgNOR count 2.5 and mean PCNA index 8.33%) and high-grade lymphomas (mean AgNOR count 8.67 and mean PCNA index 49.7%). It is suggested that both methods are useful adjuncts to histopathology for the distinction between low and high grade gastric MALT lymphomas. We also found heterogeneity in AgNOR counts and PCNA index among individual cases of either low or high grade MALT gastric lymphomas. This suggests that the AgNOR count and PCNA index is helpful in the individual approach of the proliferation rate of each tumour, a parameter of potential importance for predicting the biological behaviour of the tumour and the prognosis of the disease.

Proliferative activity of salivary gland pleomorphic adenomas and myoepitheliomas as evaluated by the proliferating cell nuclear antigen (PCNA) labeling index (LI)

Thirteen examples of pleomorphic adenoma (PA) and 4 of myoepithelioma (Me, 2 plasmacytoid cell type, 2 mixed cell type) were examined with respect to their proliferative activity on the basis of proliferating cell nuclear antigen (PCNA) immunohistochemistry. In PA, PCNA labeling index (LI) in tubular/trabecular/solid areas was significantly higher than that in myxomatous or chondroid areas. Although the mean value of LI in PA and Me was not statistically different (PA; 3.02 +/- 1.03%, Me; 3.19 +/- 1.76%), the Me of mixed cell type composed of epithelial, spindle or clear neoplastic myoepithelial cells had significantly higher LI, indicating the possibility of more rapid growth than PA. The small difference in the mean value of PCNA LI between PA and the mixed cell type of Me, however, suggests that enucleation with a margin of normal uninvolved tissue remains the recommended treatment for Me, as well as for PA.

Immunostaining for proliferating cell nuclear antigen: its role in determination of proliferation in routinely processed human brain tumor specimens

Alcohol- and formalin-fixed, paraffin-embedded samples of 71 brain tumors (35 gliomas, 22 metastatic carcinomas, 8 meningiomas and 6 other tumors) were investigated by immunocytochemistry with three different monoclonal antibodies against proliferating cell nuclear antigen (PCNA)/cyclin (19A2; 19F4; PC10). PC10 was found to work best; it is applicable to both alcohol- and formalin-fixed tumor samples. PCNA labeling indices (LIs) were compared in the same tumors with LIs obtained by Ki-67 immunostaining of frozen sections and by in vitro incubation with bromodeoxyuridine (BrdUrd); in the latter preparations, BrdUrd LIs could be compared with PCNA LIs in the very same areas of serial sections. In gliomas, PCNA LIs were 0.7-80.2% (mean 31.7%), in metastases 0-76.0% (mean 47.8%), and in meningiomas 0-53.0% (mean 19.3%). In general, PCNA LIs were highly significantly correlated with Ki-67 LIs (P = 0.0002) and BrdUrd LIs (P = 0.0001). However, when tumor subgroups are considered, only gliomas show a significant correlation with Ki-67 and BrdUrd LIs. Despite this statistical correlation, PCNA expression was out of proportion to proliferation indices as determined by both other methods in almost one third of all brain tumors. Immunocytochemistry for PCNA produces a broad spectrum of staining intensity of labeled nuclei, whose number is dependent upon the sensitivity of the immunocytochemical technique used. Thus, inter-observer and inter-laboratory variabilities in PCNA LI determination may occur. Overlapping of PCNA LIs between tumor subgroups of varying malignancy further limits the informational value for the individual case.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunoreactivity of proliferating cell nuclear antigen in salivary gland tumours: an assessment of growth potential

Immunoreactivity of proliferating cell nuclear antigen (PCNA) was assessed to evaluate growth potential in surgically resected tissue specimens from 70 cases of benign and malignant salivary gland tumours. Three stage streptavidin-biotin immunoperoxidase immunostaining using monoclonal antibody to PCNA showed a heterogeneity of PCNA index and distribution. In normal salivary gland specimens, PCNA was demonstrated in the nuclei of few ductal and acinar cells. In pleomorphic adenoma a multiple nodular growth pattern was observed with positive immunoreactivity restricted to the nuclei of tubulo-ductal structures. Warthin's tumour had positive nuclei in the outer cuboidal cells of epithelial component and germinal centres of lymphoid tissue. Myoepithelioma and acinic cell carcinoma showed slightly differing values and a statistically significant difference in the value of the index was observed in tumour cell aggregates of the cribiform type of adenoid cystic carcinoma and the solid undifferentiated type and between low/intermediate and high-grade mucoepidermoid tumours. PCNA is a useful marker of tumour cell proliferation; the index correlates with the grade of malignancy in salivary gland tumours.

Proliferation cell nuclear antigen (clone 19A2) correlates with 5-bromo-2-deoxyuridine labelling in human colonic epithelium

Measurements of cell proliferation can be used as biomarkers of preneoplastic change. In this study, two immunocytochemical methods that measure different components of the cell cycle were compared to assess cell proliferation on biopsy samples from human colonic mucosa. These methods are based on a monoclonal antibody against 5-bromo-2-deoxyuridine (BrdU), which is confined to S phase cells, and a more broad assessment of proliferation based on an antibody against proliferating cell nuclear antigen (PCNA, clone 19A2). In the PCNA assay, only strongly immunostained nuclei were included. The proliferation index was assessed in colonic mucosa from patients with no colonic disorders. Correlation between individual total proliferation indices determined by either method was significant with rs = 0.6 (p < 0.05). The mean proliferation index in the study group was 7.79% using BrdU and 7.64% using PCNA immunocytochemistry. Distribution of labelled cells within crypts was similar with respect to the two methods with a peak at the 18th and the 24th percentile in the case of BrdU and at the 23rd percentile for PCNA. Variance component analysis showed that at least two biopsy specimens should be evaluated per subject to allow a precise individual characterisation. It is concluded that PCNA (19A2) immunocytochemistry may be used as an operational marker of cell proliferation in normal colonic mucosa. A significant correlation and an agreement in the mean proliferation index between PCNA (19A2) and BrdU can only be achieved by a strictly standardised enumeration of labelled cells limited to strongly stained nuclei in the PCNA evaluation.

Early interstitial changes in hypertension-induced renal injury

To elucidate the mechanisms of hypertensive renal injury, we investigated the time course and extent of changes in matrix composition, as well as cell proliferation and infiltration in two-kidney, one clip rats. The nonclipped kidneys from hypertensive and sham-operated control rats (n = 5 to 10 in each group) were studied at 7, 14, 21, and 28 days after clipping. Systolic blood pressure was elevated by day 7 (154 +/- 3 versus 111 +/- 4 mm Hg in sham group, P < .001, n = 10 each). Hypertension resulted in an early expansion of the interstitial volume by 37%, whereas hypertensive vascular changes and glomerular injury did not become evident until day 21. Immunofluorescence studies revealed an early interstitial accumulation of collagens I, III, IV, V, VI, and fibronectin by day 7. In contrast, the glomeruli showed a mild to moderate increase in collagens I, III, IV, V, laminin, and fibronectin but not collagen VI later in the established phase of hypertension. Staining for proliferating cell nuclear antigen as a marker of cell replication was increased in tubular epithelial but not interstitial or glomerular cells. A progressive infiltration of macrophages (16 +/- 2 versus 9 +/- 1 ED1+ cells/mm2, P < .05, n = 6) and T lymphocytes (93 +/- 15 versus 74 +/- 7 CD4+ cells/mm2, n = 8) in the cortical interstitium had already occurred by day 7. On the other hand, only macrophages increased in number within the glomeruli. Thus, renovascular hypertension leads to an early tubular cell proliferation, mononuclear cell recruitment, and deposition of matrix proteins primarily within the interstitium. We conclude that the injury producing nephrosclerosis in this model extends far beyond the glomeruli. Both the tubules and the interstitium are actively involved and may be the more important initial sites of injury.

Proliferating cell nuclear antigen (PCNA) immunoreactivity in ovarian serous and mucinous neoplasms: diagnostic and prognostic value

Sixty-two serous and mucinous ovarian tumors, an admixture of benign, borderline and malignant neoplasms, were immunostained for proliferating cell nuclear antigen (PCNA), with the monoclonal antibody PC10. The PC10 index, the proportion of cells showing nuclear positive staining, was calculated in each case. All the tumors showed positive immunoreactivity for PCNA. There was no overlap of PC10 counts between benign, borderline and malignant serous tumors but within the mucinous group of neoplasms there was considerable overlap between the counts for borderline and malignant tumors. There was no relationship between the PC10 index and the surgical stage of the malignant neoplasms and the index could not be correlated with patient death. Staining for PCNA does not, therefore, appear to be of any prognostic value in ovarian adenocarcinomas.

p53 immunoreactivity in cutaneous PUVA tumors is similar to that in other non-melanoma skin neoplasms

Expression of the p53 tumor suppressor gene product was determined in keratoses and skin cancers associated with psoralen photochemotherapy (PUVA). An immunocytochemical study was employed using CM-1 (polyclonal) and Do-1 (monoclonal) antibodies to human wild-type p53. Thirty-two cutaneous lesions and 20 perilesional PUVA-irradiated skin biopsies were examined from 7 patients, all of whom had received more than 200 PUVA treatments and/or a cumulative UVA dose of greater than 1000J/cm2 as treatment for widespread plaque psoriasis. p53 immunoreactivity was seen in 7 of 15 squamous cell carcinomas (46.7%), 5 of 8 dysplastic keratoses (62.5%) and in no basal cell carcinomas or benign keratoses. The overall prevalence of p53 immunoreactivity in 46.2% of malignant or dysplastic PUVA-associated skin tumors is similar to that previously found by our group in comparable skin tumors from the general population. Most patients with lesions showing positive p53 immunoreactivity had, however, been exposed to additional risk factors before receiving PUVA therapy. p53 gene sequencing of PUVA-associated non-melanoma skin cancer (NMSC) may clarify whether p53 mutation contributes to the development of these tumors and whether this relates to PUVA therapy or prior carcinogen exposure.

Patterns of immunohistochemical staining for proliferating cell nuclear antigen and p53 in benign and neoplastic human endometrium

Immunohistochemical staining was carried out on a spectrum of normal, hyperplastic and malignant endometrial curettings, for proliferating cell nuclear antigen--PCNA (using the monoclonal antibody PC10) and for abnormally stabilized p53 (using the polyclonal antibody CM-1). The mean proportion of glandular epithelial cells showing PCNA immunoreactivity was significantly lower in atypical hyperplasia/intra-endometrial adenocarcinoma than in invasive adenocarcinoma, but the degree of overlap between the cases was such that this was not considered to be of diagnostic value. p53 immunoreactivity was detected in 47% of invasive adenocarcinomas and in a much smaller proportion of endometria showing simple hyperplasia and atypical hyperplasia, but staining was only focal in the last two conditions. The majority of p53-positive invasive adenocarcinomas had a large proportion of glandular epithelial cells expressing PCNA, but a significant number of p53-negative cases also had a high PC10 index. This suggests that, in endometrial neoplasia, there is not a simple relationship between abnormally stabilized p53 and PCNA expression.

Comparative immunohistochemical studies of p53 and proliferating cell nuclear antigen expression and argyrophilic nucleolar organizer regions in pancreatic duct cell carcinomas

Thirty-eight cases of pancreatic duct cell carcinoma were examined for p53 expression and proliferating cell nuclear antigen (PCNA) by enhanced immunohistochemistry, as well as for changes in numbers of argyrophilic nucleolar organizer regions (AgNORs). Fifteen cases (39.5%) showed p53 overexpression, which tended to increase in proportion to the histopathological grading of malignancy. However, tumor stage and lymph node status were not correlated to p53 overexpression. PCNA labeling index (LI) increased with both histologically malignant grading and pathological stage, but was not correlated with lymph node status. The expression of p53 and PCNA thus did not necessarily reflect the degree of malignant development. In contrast, AgNOR number showed statistically significant correlations with these three indicators of malignancy. A comparative analysis of p53, PCNA LI and AgNOR number showed overexpression of p53 to be correlated to PCNA LI and essentially unrelated to AgNOR number. The present results thus indicate a close relation between p53 and PCNA, while AgNORs appear to be regulated separately from either of them.

EGFR and PCNA expression in oral squamous cell carcinomas--a valuable tool in estimating the patient's prognosis

We investigated 100 cases of oral squamous cell carcinomas immunohistologically with respect to the expression of the epidermal growth factor receptor (EGFR) and the proliferating cell nuclear antigen (PCNA). The results were correlated with a new malignancy grading of the invasive tumour areas and the clinical outcome of the patients to estimate the individual prognosis. In conclusion, the amount of antigen expression of both antigens increases with the increasing grade of malignancy of the oral squamous cell carcinoma. Furthermore, there is a statistically significant correlation between the amount of antigen expression and the patient's prognosis. An overexpression of EGFR and PCNA is associated with a short survival of the patient. Both antigens detect relevant tumour biological parameters and are worthy factors in estimating the individual prognosis in patients suffering from oral squamous cell carcinomas.

Immunohistochemical evidence for the expression of proliferating cell nuclear antigen (PCNA) by non-proliferating hepatocytes adjacent to metastatic tumours and in inflammatory conditions

The possibility that proliferating cell nuclear antigen (PCNA) is expressed by non-proliferating liver cells was investigated. Liver biopsies from 107 patients were investigated, which included histologically normal liver, metastatic tumour, and inflammatory lesions. PCNA was detected using immunohistochemical staining with the monoclonal antibody PC10. This was compared with the proportion of proliferating cells as assessed by immunostaining for the Ki-67 antigen using the monoclonal antibody MIB 1. Most cases of histologically normal liver showed few PC10-positive cells. PCNA-positive hepatocytes far outnumbered those positive with MIB 1 in specimens showing metastatic tumour or an inflammatory cell infiltrate. There was no relation between the degree of PCNA overexpression and the type of tumour present or the nature of the inflammatory lesion. Other cell types, including the biliary epithelium, did not show this large difference between the proportions of PC10- and MIB 1-positive cells. It is concluded that non-proliferating hepatocytes increase their levels of PCNA in a wide variety of pathological conditions. This may be mediated by cytokines released by tumour cells or inflammatory cells.

Proliferating cell nuclear antigen distribution in keratoacanthoma and squamous cell carcinoma

Histologic differentiation of keratoacanthoma (KA) and squamous cell carcinoma (SCC) is often difficult despite well-delineated histopathologic criteria. This has prompted a search for more objective methods to differentiate these two lesions. In the present study, we immunohistochemically examined the distribution of proliferating cell nuclear antigen (PCNA)-positive cells in 11 cases of KA, 7 cutaneous SCC, and 2 atypical squamous proliferations (for which a definitive diagnosis could not be made on routine histology) using a commercially prepared anti-PCNA monoclonal antibody. We found PCNA-positive cells predominantly in the periphery of squamous nests in KA. In contrast, SCC showed a diffuse staining pattern with PCNA-positive cells seen throughout squamous nests. Determining the pattern of PCNA-positive cells is easy, does not require cell counting, and may provide additional histochemical data facilitating the distinction between KA and SCC.

Proliferative activity of primary cutaneous melanocytic tumours

The expression of proliferating cell nuclear antigen (PCNA) was examined in formalin-fixed paraffin-embedded tissue sections from 41 lesions (27 melanocytic nevi, 3 atypical nevi and 11 malignant melanomas) to determine the proliferative activity of primary cutaneous melanocytic tumours. Most of the malignant melanomas had more than 7% PCNA-positive cells (9.2 +/- 0.5%), while the melanocytic nevi manifested less than 1% PCNA-positive cells (0.4 +/- 0.1%). Atypical nevi exhibited an intermediate, but still significantly lower, labelling ratio when compared with malignant melanomas (0.8 +/- 0.2%). The proliferative activity of the lesions was compared between portions at different depths in the skin (epidermal, upper dermal and lower dermal location). In cases of malignant melanoma, the proliferative activity was higher in the deeper portion of dermis whereas PCNA-positive cells in melanocytic nevi were located in the upper dermis predominantly. Thus the PCNA labelling ratio of malignant melanoma and/or melanocytic nevus cells located in the epidermodermal junction was not necessarily higher than that of malignant melanoma and/or melanocytic nevus cells in the dermis. These results indicate that staining with PCNA would be very useful in the differentiation of malignant melanoma from melanocytic nevi manifesting cellular and/or structural atypia by virtue of a significant difference in the proportion of PCNA-positive cells. Although malignant melanomas have higher proliferative activity than melanocytic nevi in the deeper dermis, junctional activity in melanocytic tumours does not indicate cell proliferation.

Current topics of immunohistochemistry as applied to skin tumors

Suppressor oncogene p53 is expressed more frequently in the nodular portion than the superficial spreading portion of the same melanoma. PCNA expression follows the same pattern but it is strongly expressed already in the superficial spreading portion. CD34 is found to label dermatofibrosarcoma protuberans. There is the mixture of negative strands but the immunostains are predominantly positive in the three cases studied. Neurogenic tumors are reactive but the intensity of staining is only moderate. Fibrous histiocytoma, dermatofibroma and other fibrohistiocytic tumors are non-reactive. CD34 is expressed in the outer root sheath of hair follicle below the sebaceous gland level. A case of piloepidermal cyst is CD34 positive. CD34 is expressed in vascular endothelial cells; not only hemangiomas but also lymphangiosarcoma is CD34 positive. A case of indeterminate cell histiocytosis following scabies and superficial variant of clear cell sarcoma are discussed as examples of new entities.

Increased PCNA/cyclin index correlates with severity of duodenitis defined by histological criteria

The proliferative activity of crypt epithelial cells was studied in 64 duodenal biopsies using immunohistochemistry and proliferating cell nuclear antigen (PCNA)/cyclin monoclonal antibodies in alcohol-fixed paraffin-embedded sections. A positive correlation between duodenitis as defined by histological criteria and increased mean percentage of PCNA positive crypt cell nuclei (PCNA index) was found. The mean PCNA index in normal mucosa was 11.8 +/- 2.7% (mean +/- SD), in mild (grade 1) duodenitis 17.3 +/- 3.9%, in moderate (grade 2) 30.6 +/- 6.9%, and in severe (grade 3) duodenitis 41.1 +/- 8.5%. The inclusion of PCNA index, which is easily measured in paraffin-embedded sections, in the existing histopathological grading systems of duodenitis may improve their clinical relevance.

Cell proliferation in breast tumours: analysis of histological parameters Ki67 and PCNA expression

Ki67 and Proliferating Cell Nuclear Antigen (PCNA) are antigens expressed in the nucleus during various phases of cell division, which can be detected immunohistochemically using monoclonal antibodies. Thirteen fibroadenomas and 39 carcinomas were examined for expression of Ki67 and PCNA. A staining index was calculated for each tumour as the percentage of positive cells in the areas of highest density. The mean index for both antibodies was significantly lower in fibroadenomas than in malignant tumours. A wide range of proliferation rates was seen in the malignant group; the mean Ki67 index of Grade I carcinomas was 9% +/- 4.4 (mean +/- SD), of Grade II 14.3 +/- 8.7 and of Grade III 26.2 +/- 15.7. These differences are statistically significant. In malignant tumours there was a good correlation between the mitotic count and the Ki67 index (r = 0.61, p < 0.005) but none between the mitotic count and PCNA index. There was a weak correlation between the Ki67 and the PCNA indices (r = 0.38 p < 0.005), but no correlation was found between either index and oestrogen receptor status, patient age or tumour size. Ki67 immunohistochemistry is a convenient method for assessing cell proliferation, applicable in most laboratories. The validity of measuring proliferation in this way has yet to be established but the wide variation of expression even within the conventional grading categories may help to discriminate prognostically distinct subgroups. Expression of PCNA appears to correlate poorly with Ki67 expression in breast tumours and not with mitotic count; therefore its usefulness as a marker of proliferative activity, on current evidence, appears to be limited.