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

Prognostic significance of proliferating cell nuclear antigen expression in colorectal cancer

BACKGROUND

Recognition of a biologic marker in colorectal cancer tissue that correlates with recurrence and poor survival would offer a rationale for planning aggressive adjuvant therapy. This study assessed the prognostic significance of proliferation activity in cancer cells and nonneoplastic epithelial cells in patients with colorectal cancer, using proliferating cell nuclear antigen (PCNA) immunohistochemical analysis.

METHODS

A mouse monoclonal antibody that reacted with PCNA was used to measure proliferation indexes in neoplastic and nonneoplastic colonic tissues of two sex-matched and age-matched groups of 40 patients with different clinical outcomes. In one group of 20 patients, there was no evidence of recurrence or residual disease after a median follow-up of 5.3 years. In the other group, all 20 patients had died within 3.6 years of recurrent disease.

RESULTS

The proliferation indexes in both cancer cells and epithelial cells of adjacent nonneoplastic crypts were elevated significantly in those who died compared with survivors; this finding was independent of other variables. There was evidence of an upward shift in the proliferation compartment of the normal crypt that occurred to the same extent in both patient groups. No correlation between Dukes stage and any of the proliferation indexes was observed.

CONCLUSION

Proliferation indexes in neoplastic and adjacent normal mucosa, as defined by PCNA immunohistochemical analysis, are independent predictors of recurrence and poor survival in patients with colorectal cancer, indicating that they may be helpful as predictors of long-term survival and in planning prophylactic adjuvant therapy.

Immunohistochemical assessment of cellular proliferation in the developing human CNS using formalin-fixed paraffin-embedded material

Assessment of cell proliferation in the developing human brain has been limited to counting mitotic cells, since the other procedures currently used for determination of the mitotic activity either depend on experimental manipulation of the tissue, e.g., labeling with radioactive thymidine precursors or with bromodeoxyuridine, or on frozen sections of the tissue, e.g., Ki-67 immunoreactivity. As most of the developing human brain material available is formalin fixed and paraffin embedded, these procedures are not practical. An immunohistochemical technique based on a monoclonal antibody directed against a proliferating cell nuclear antigen (PCNA) was used for detecting cellular proliferation in the developing human brain. Known progenitor cells in proliferating zones showed distinct PCNA-reactivity, but the method also revealed new areas of cell proliferation in fixed paraffin-embedded tissue blocks from the developing human brain.

A role for proliferative measurements in clinical oncology?

I feel a simple but properly determined proliferative measurement is within our grasp for clinical use. In addition, multi-parametric flow cytometry offers a means of obtaining more detailed cell kinetic information, using DNA staining combined with staining with one or more antibodies directed against either BrdUrd or proliferation-related proteins.

Cell kinetic and morphological studies of human cholangiocellular carcinoma

We investigated the cell kinetics and morphologies of cholangiocellular carcinoma (CCC) using 48 autopsied or surgically resected cases (47 were adenocarcinoma and the remaining adenosquamous cell carcinoma), all of which were formalin-fixed and paraffin-embedded. Cell kinetics were analyzed by counting the number of argyrophilic nucleolar organizer regions (AgNOR) using immunostaining of proliferating cell nuclear antigens (PCNA) and flow cytometric DNA analysis. Dedifferentiation of CCC was positively correlated with AgNOR number (2.22 +/- 0.21 in well differentiated, 3.66 +/- 0.85 in moderately differentiated and 4.17 +/- 0.49 in poorly differentiated adenocarcinomas, respectively). In 22 cases, the labeling index (LI) of PCNA was higher in moderately and poorly differentiated adenocarcinomas (24.0 +/- 2.35 and 26.0 +/- 4.89, respectively) than in well differentiated ones (10.8 +/- 2.14). A majority of well differentiated ones were diploid, while aneuploidy prevailed in moderately to poorly differentiated ones. These data suggest that cell proliferative indices and nuclear DNA analysis of CCC accurately reflect their histological grading. The anatomical location of CCC along the biliary tree had no relation to either of the cell kinetic data. In autopsy cases, the patients with organ and lymph node metastases tended to show a higher DNA index and aneuploidy. This study implies that a combination of several cell kinetic data is valuable for the evaluation of the biological behaviors of CCC, and also supports further studies of cell kinetics of CCC using small-sized biopsy specimens, as a prognostic indicator.

PC10 monoclonal antibody to proliferating cell nuclear antigen as probe for cycling cell detection in developing tissues. A combined immunocytochemical and flow cytometric study

Proliferating cell nuclear antigen (PCNA), also referred to as cyclin, is an auxiliary protein to DNA-polymerase delta and a proposed marker of replicating cells. We have investigated the applicability and limitations of PC10 monoclonal antibody to PCNA in a cell kinetics study of developing human and rat tissues by immunocytochemical and flow cytometric techniques. Our data demonstrate that the epitope recognized by PC10 antibody is resistant to wax embedding, but sensitive to aldehyde fixation; conversely, alcoholic fixative solutions preserve the immunoreactivity to PC10. Tissue distribution, DNA content and bromodeoxyuridine uptake confirm that PC10-immunoreactive cells in alcohol-fixed tissues are cycling (G1-, S- and G2-phases traversing) cells. It is concluded that the PC10 antibody can be regarded as a powerful tool to study cell kinetics and differentiation in developing tissues, provided that the tissue processing is adequate.

Immunohistochemical study of PCNA (proliferating cell nuclear antigen) in normal and abnormal endometrium

To investigate the cell kinetics of human endometrial disorders immunolocation of PCNA (proliferating cell nuclear antigen) was performed in 69 specimens of normal, hyperplastic, or malignant endometrial tissue that had been fixed in formalin and embedded in paraffin. Immunoreactivity of PCNA was observed in all specimens examined. In the proliferative phase, PCNA positive cells were present in both the glands and stroma. In the secretory phase PCNA positive cells were seen principally in the stromal cells. A PCNA labeling index was obtained by counting one thousand cells per case. PCNA positivity in the proliferative phase was significantly higher than in the secretory phase (P < 0.01), but lower than in moderately differentiated (P < 0.01) or poorly differentiated (P < 0.05) adenocarcinoma. No significant differences in the PCNA labeling index were observed between hyperplasia and adenocarcinoma. These findings indicate that possible biologic differences between these proliferative endometrial lesions are probably not due to differences in cell proliferative activity, but rather to factors other than proliferation such as their ability to invade.

Combined proliferating cell nuclear antigen and morphometric analysis in the diagnosis of cutaneous lymphoid infiltrates

AIMS

To evaluate the use of morphometry in the diagnosis of benign and malignant cutaneous lymphoid infiltrates; and to determine whether the sensitivity of detection of cutaneous T cell lymphoma (CTCL) could be improved by selectively measuring cells expressing proliferating cell nuclear antigen (PCNA).

METHODS

44 archival biopsy specimens were studied. These included cases of CTCL, non-specific chronic dermatitis, lichen planus and lupus erythematosus. PCNA was identified using a standard immunohistological technique. Reactive cells were identified using automatic colour discrimination, and the size and shape were determined interactively. Similar measurements were made on the total dermal lymphocyte population.

RESULTS

There was no significant difference between the proportions of PCNA reactive cells in any of the diseases studied. The PCNA positive lymphocytes in CTCL were larger than those in lupus erythematosus and lichen planus and were more irregular in shape than those in chronic dermatitis. Differences were also seen in the total lymphocyte population. Plotting cell size and shape(fcircle) for PCNA cells together allowed CTCL to be differentiated from the inflammatory disorders with a sensitivity of 80% and a specificity of 93%. This was better than could be achieved using measurements made on the total cell population.

CONCLUSIONS

This technique can be partly automated and could be useful in the differential diagnosis of cutaneous lymphoid infiltrates. The result are also of some interest in the further understanding of patterns of cell proliferation in skin associated lymphoid tissue.

Malignant change in trichilemmal cysts: a study of cell proliferation and DNA content

We have examined proliferative activity in a series of pilar and trichilemmal cysts using an antibody to proliferating cell nuclear antigen. In benign lesions proliferative activity was confined to the basal layers of the squamous epithelium. Lesions showing malignant change showed increased proliferative activity and were not confined to the basal layer. These findings were correlated with studies on DNA content using flow cytometry.

Increased expression of p34cdc2 and its kinase activity in human gastric and colonic carcinomas

We examined the expression of p34cdc2 and its kinase activity in human gastric and colonic carcinoma cell lines and carcinoma tissues and studied its relation with a tumor-suppressor gene product, p53. All the gastric and colonic cancer cell lines expressed p34cdc2 and showed its kinase activity at various levels. When the cells were arrested in mitotic metaphase by the use of nocodazole, p34cdc2 kinase activity was induced and p53 was apparently phosphorylated. Of 12 gastric carcinoma cases, 11 (91.7%) showed higher p34cdc2 kinase activity in tumor tissues than in corresponding non-neoplastic mucosa. The protein kinase activities in the individual cases were well correlated with the levels of p34cdc2 protein expression. A good correlation was also found between the expression of p34cdc2 and proliferating cell nuclear antigen (PCNA). Almost all the colonic carcinomas showed higher cdc2 kinase activity and increased p34 expression when compared with non-neoplastic mucosa. Interestingly, most of the gastric and colonic carcinomas having high cdc2 kinase activity expressed high levels of p53. These findings suggest that the increased p34cdc2 kinase activity might cause the development and proliferation of gastric and colonic carcinomas, partly through abnormal p53 accumulation.

Proliferating cell nuclear antigen (PCNA) expression and nuclear DNA content in predicting recurrence after radiotherapy of early glottic cancer

Proliferating cell nuclear antigen (PCNA) is a DNA replication protein maximally elevated in late G1 and S phases of the cell cycle. By using monoclonal antibodies, the expression of PCNA can be quantified and the rate of tumour cell proliferation estimated. The degree of DNA aberration in a tumour cell population reflects its genetic instability and has been implicated as a prognostic factor in an increasing number of solid tumours. The nuclear DNA content can be assessed by densitometric image cytometry DNA analysis. Both PCNA and DNA analysis can be performed on histological sections from paraffin embedded biopsies. In search of efficient and reproducible methods to identify early glottic cancers with increased risk for recurrence after radiotherapy, the PCNA expression as well as the DNA content of the diagnostic biopsies from 28 T1N0M0 glottic cancers were assessed. The group of tumours which recurred locally after radiotherapy displayed lower PCNA expression and higher DNA aberration than the group of tumours which were cured. Moreover, a combination of both parameters improved the possibility to discriminate the two groups. For T1 glottic cancer displaying high grade of genetic instability or low grade of proliferation, treatment regimes other than radiotherapy and closer follow-ups could be considered.

Cellular proliferation in the anterior pituitary gland of normal adult rats: influences of sex, estrous cycle, and circadian change

Proliferative activity of the anterior pituitary gland in 10 week-old male and female rats under normal conditions was investigated by counting mitotic figures and using single and double immunostaining of 5-bromo-2'-deoxyuridine (BrdU), proliferating cell nuclear antigen (PCNA), and six pituitary hormones. To determine which proliferative changes depend on the estrous cycle and circadian changes, respectively, six groups of female and two groups of male rats were studied at various times of day. Additionally, BrdU-incorporated cells were further classified by the six types of hormones they contained, or as immunonegative cells. Cell proliferative activity in the females fluctuated drastically with the highest activity in estrus and the lowest in diestrus. In the males, proliferative activity was at a relatively low level, and was similar to that in females in proestrus or early estrus, with the greater activity at night. Identified by their pituitary hormones, the distribution of the proliferating cells was almost the same in each sex, with prolactin (PRL) cells accounting for the highest proportion, followed by growth hormone (GH) cells, and adrenocorticotropic hormone (ACTH), luteinizing hormone (LH), follicle stimulating hormone (FSH), and thyroid stimulating hormone (TSH) cells. These percentages agreed well with previously reported levels of cell types among all pituitary cells of the rat. It is therefore suggested that the life span and cycle of rat pituitary cells does not differ among cell types. In another test, male and female rats were given BrdU continuously via an osmotic pump for 8 days to compare cell proliferative activity between sexes, exclusive of the influence of estrous cycle and circadian changes. In this way, we were able to demonstrate that the cumulative incorporation of BrdU in females was consistently twice as high as in males over a constant period of time, and to conclude that cell renewal occurs at a doubled rate in the pituitary of female rat.

Correlation between [3H]thymidine and proliferating cell nuclear antigen (PCNA)/cyclin indices in archival, formaldehyde-fixed human colorectal tissues

Sections were obtained from archival colorectal tissue samples preserved in paraffin since 1974, after an in vitro incubation with [3H]thymidine and fixation in formaldehyde. These sections were submitted to immunohistochemical staining with the 19A2 monoclonal antibody against proliferating cell nuclear antigen (PCNA) (i.e. the PCNA identified as the auxiliary protein to DNA polymerase delta), followed by autoradiography. Analysis of this double-labelled material revealed an excess of PCNA-labelled over 3H-labelled nuclei, as expected from our previous studies with this fixative. On the other hand, PCNA positive nuclei showed the same overall topographical distribution as the [3H]thymidine-labelled ones, eventually revealing the same heterogeneity or abnormality in the spatial distribution of proliferative cells. Finally, there was a highly significant correlation (r = 0.898; P < 0.0001) between the [3H]thymidine labelling index (TLI) and the proportion of PCNA-positive nuclei (PCNAF-LI). PCNA immunostaining after formaldehyde fixation thus appears as a valid approach for mapping the proliferative compartment and demonstrating tumour heterogeneity or abnormalities in the distribution of proliferative cells. The excellent correlation between the PCNAF-LI and the TLI also makes PCNA immunostaining a simple tool for retrospective or prospective studies on pathological material aimed at evaluating the potential relevance of proliferative indices to clinical prognosis or prediction of cancer risk.

The immunohistochemical expression of proliferating cell nuclear antigen (PCNA/cyclin) in malignant and benign epithelial ovarian neoplasms and correlation with prognosis

Proliferating cell nuclear antigen (PCNA)/cyclin is considered to be a marker of cell proliferation. The aim of this study was to evaluate the expression of PCNA/cyclin in epithelial ovarian neoplasms (EON) as well as the possible correlation with degree of differentiation, tumour stage and overall survival. The material consisted of 34 benign and 40 malignant EON. Positive nuclear staining was detected in 2/34 (6%) of benign and 23/39 (59%) malignant EON (P < 0.001). Most cases in the high proliferation group were diagnosed in advanced clinical stages. There was no difference in overall survival between nuclear PCNA positive and negative patients, as well as the high and the low proliferation group. In conclusion, the role of PCNA as a marker of malignant potential and prognosis in EON merits further investigation.

Symmetrical neurofibroma with Schwann cell predominance and focal formation of microneurinomas

A case of symmetrical neurofibroma with onion bulbs in various stages of development and progression to microneurinomas is presented. Immunohistochemistry with differentiation and growth factor markers as well as electron microscopy showed a Schwann cell origin of the concentrically arranged cells. The onion bulbs differed from those of hypertrophic neuropathy by their more compact structure. A partial expression of cellular proliferation markers in the onion bulbs was consistent with a multifocal proliferative activity, confirming the neoplastic nature of the lesion.

Grading of soft tissue sarcomas: experience of the EORTC Soft Tissue and Bone Sarcoma Group

A practical grading system for soft tissue sarcomas was developed, based on 282 eligible patients entered in an EORTC adjuvant clinical trial. The primary tumours in this trial had to be adequately treated. Histopathological parameters, which appeared significant in two preceding studies, were tested. These parameters were differentiation of the tumour, presence and amount of necrosis, the presence and amount of myxoid areas and the number of mitoses. In addition, the size of the tumour was also analysed. The quantitative data (mitotic count and size of the tumour) were not a priori grouped, but were divided into categories based on the results of the statistical analysis. Based on a multivariate analysis only mitotic count, the presence or absence of necrosis and the size of the tumour were significantly correlated with the duration of survival or the time to distant metastases. Of these parameters, the mitotic count was the most important.

Use of proliferation cell nuclear antigen immunoreactivity for distinguishing hydropic abortions from partial hydatidiform moles

AIMS

To determine whether the expression of proliferating cell nuclear antigen (PCNA) in villous cytotrophoblast could distinguish between placental tissue from a hydropic abortion and that from a partial hydatidiform mole.

METHODS

Tissue from 18 partial hydatidiform moles, 15 hydropic abortions, five normal first trimester placentas and five normal full term placentas were immunostained for expression of PCNA, using the monoclonal antibody PC10.

RESULTS

PCNA immunoreactivity was very much higher in the cytotrophoblast of normal first trimester placentas than in normal term placentas. Villous tissue from partial hydatidiform moles showed, on average, less immunoreactivity for PCNA than did villous tissue from hydropic abortions.

CONCLUSIONS

Immunostaining for PCNA is of no value for differentiating between partial hydatidiform moles and hydropic abortions. The findings indicate that trophoblastic proliferation or hyperplasia is not a feature of partial hydatidiform moles.

Cell proliferation in breast carcinoma assessed by a PCNA grading system and its relation to other prognostic variables

This study was undertaken to relate the expression of the proliferating cell nuclear antigen (PCNA), a proliferation marker of putative prognostic significance, to some more established prognostic factors in a series of 60 consecutive breast cancer surgical specimens. PCNA was detected by the PC10 monoclonal antibody (MAb) using an immunohistochemical method and PCNA immunostaining was estimated on a semiquantitative basis, a cut-off value of 50% of positively stained tumour cells discriminating between the high (> 50%) and low (< 50%) PCNA grade. The PCNA grade did not correlate with tumour size and axillary node status. However, a high PCNA grade tended to be associated with a poor histological grade and there was an inverse relationship with oestrogen-receptor status, as determined by means of the immuno-histochemical staining for the oestrogen-induced pS2 protein. These conflicting results suggest that the possible prognostic usefulness of PCNA immunostaining, as a measure of cell proliferation rate, in breast cancer is yet to be demonstrated and can be validated only by direct relation to survival data.

Interstitial cells from the atrial and ventricular sides of the bovine mitral valve respond differently to denuding endocardial injury

The mitral valve has atrial and ventricular sides, each lined by endocardial cells. The valve stroma contains alpha smooth muscle actin positive interstitial cells, collagen, glycosaminoglycans, and elastic tissue. To eliminate the effect of endocardium on wound repair in bovine mitral valve organ culture, the endocardium was removed from both sides of the valve. At 6 days, organ cultures of these preparations revealed surface cells on the ventricular side but not in the atrial side. Ventricular surface cells were negative for Factor VIII-related antigen, and positive for alpha smooth muscle actin. Immunoperoxidase staining for proliferating cell nuclear antigen/cyclin, a marker for cell proliferation, revealed a positive labeling index of (mean +/- standard deviation) 0.08 +/- 0.16% for interstitial cells from the atrial side and 0.14 +/- 0.19% for ventricular side interstitial cells in uncultured preparations (not significant), and 0.44 +/- 0.69% for atrial side interstitial cells and 2.25 +/- 1.64% for ventricular side interstitial cells in the cultured preparations (significant, P < 0.0006). The results suggest that in organ culture, interstitial cells from the ventricular side of the mitral valve respond to a denuding endocardial injury by proliferating and migrating onto the adjacent surface whereas interstitial cells from the atrial side do not. This difference in the response to injury of interstitial cells from the atrial and ventricular sides of the valve may reflect differences in phenotype or may be due to effects of extracellular matrix on interstitial cell behavior. The latter is possible because of differences in the extracellular matrix of the atrial and ventricular sides of the valve.

The pathology of arteriovenous malformations of the brain treated by embolotherapy. II. Results of embolization with multiple agents

Light microscopic and immunohistochemical examination was undertaken of intracranial arteriovenous malformations (AVMs) surgically resected from 18 patients, each of whom had undergone preoperative angiographic embolization with multiple agents. Distinct patterns of tissue reaction to these agents were noted, even when more than one substance was present in a vascular lumen. Avitene produced the mildest tissue response but resulted in relatively early endothelialization and recanalization. Cyanoacrylates were longer-lasting but associated with more acute and chronic (including granulomatous) inflammation and vessel wall changes. Polyvinyl alcohol foam/ethanol mixture had intermediate properties. Endothelial proliferation over embolization material was confirmed using immunohistochemical application of an antibody to cell proliferation-specific proteins. The significance of these findings for combined endovascular and surgical treatment of cerebral vascular malformations is discussed.

Toxicological and pathological applications of proliferating cell nuclear antigen (PCNA), a novel endogenous marker for cell proliferation

A major stimulus to study cell proliferation, particularly in rodent carcinogenicity assays and human tumors, has been the belief that the quantification of this fundamental biological process will provide the toxicologist and pathologist with objective data allowing a better understanding of the mechanisms involved in the toxicity and/or carcinogenicity of certain compounds as well as guiding more effective management of patients afflicted with neoplasia. Among the markers used for cell proliferation measurement, PCNA has recently gained much attention and holds much promise as it is intricately involved in the cell replication processes. It not only could allow measurement of the replication rates without necessitating pretreatment of the animal/tissue in prospective studies, but also would allow retrospective assessment of the proliferative rates in archival tissues due to the conservation of this marker in fixed and paraffin-embedded tissues. Finally, knowledge of the function of PCNA in the cell cycle and its regulation by other factors may help us understand the advantages and limitations of PCNA as a cell proliferation marker in its application in toxicology and as a prognostic marker in human tumors.

Spermidine/spermine N1-acetyltransferase, a new biochemical marker for epithelial proliferation in rat bladder

We examined the activity of spermidine/spermine N1-acetyltransferase (SAT), a rate-limiting enzyme of the biodegradation of polyamines, in N-butyl-N-(4-hydroxybutyl)nitrosamine-induced transitional cell carcinoma (TCC) and melamine-induced papillomatosis of rat bladder, and compared the activity to that of ornithine decarboxylase (ODC). Both activities were higher in both lesions than in control rats. The difference between SAT and ODC activities in cancerous tissue and papillomatosis was not significant. Cells stained for proliferating cell nuclear antigen (PCNA) were abundant in papillomatosis. TCC had areas with much PCNA. The results indicated that an elevation of SAT activity occurs in both reversible and irreversible proliferation of bladder epithelium and could be important in bladder carcinogenesis.

Reactive proliferation of astrocytes studied by immunohistochemistry for proliferating cell nuclear antigen

Astrocyte proliferation in the stab-wounded cerebral cortex of mice was studied using double immunohistochemistry for proliferating cell nuclear antigen (PCNA) and glial fibrillary acidic protein (GFAP). The number of GFAP-positive astrocytes increased markedly from day 0.5 to day 3 after stab wounding. Some GFAP-positive astrocytes in the immediate vicinity of the wound were found to be positive for PCNA. However, the maximum number of these double positive astrocytes was only 5-6% of the number of GFAP-positive astrocytes. This maximum value was observed on days 2.5 and 3. The present study revealed that astrocytes are able to reactively express PCNA, an intrinsic marker of DNA replication. On the other hand, it is suggested that the proliferation of astrocytes in the wounded cerebral cortex is limited, in contrast with their marked reactive up-regulation of GFAP.

Argyrophilic nucleolar organizer region counts and proliferating cell nuclear antigen scores are two reliable indicators of survival in pharyngeal carcinoma

The proliferative activity of pharyngeal carcinoma has been investigated by means of monoclonal antibody PC10 against proliferating cell nuclear antigen (PCNA/cyclin) and argyrophilic nucleolar organizer region (AgNOR) analysis in formalin-fixed, paraffin-embedded biopsies from 45 primary squamous and undifferentiated carcinomas, prior to therapy. The correlation between AgNOR counts and PCNA(PC10) scores was highly significant (r = 0.73; P < 0.0001) as determined by Pearson's correlation coefficient. Moreover, the univariate Kaplan-Meier survival analysis showed a significant correlation between 3- and 5-year survival rates and the mean AgNOR number per tumour cell (P = 0.0003) or the percentage of PCNA(PC10)-positive cells (P = 0.0001). Our results indicate that both AgNOR counts and PCNA(PC10) scores are reliable markers of the proliferative activity of pharyngeal carcinoma in small, routinely processed biopsies, in which they can allow simultaneous evaluation of the histology and tumour cell kinetics.

Proliferating cell nuclear antigen (PCNA) in common epidermal lesions.. An immunohistochemical study of proliferating cell populations

A commercially available antibody to proliferating cell nuclear antigen was used to characterize and compare proliferating cell populations in paraffin sections of benign, premalignant, and malignant lesions of human epidermis using routine immunohistochemical techniques. Three patterns emerged. An ordered pattern was found in prurigo nodularis and keratoacanthoma, wherein moderately and strongly positive nuclei were distributed in a continuous, basal-suprabasal layer of relatively uniform thickness. There was graded loss and ultimate extinction of PCNA staining in progressively more superficial epidermal cells. A basal dysplastic pattern was found in actinic keratosis and squamous cell carcinoma. Nuclei of essentially all dysplastic cells of both categories expressed PCNA, with a preponderance of strongly positive nuclei. These were localized to basal-suprabasal zones that were often expanded. Loss of PCNA reactivity toward the surface was often abrupt. Bowen's disease exhibited a diffuse dysplastic pattern, wherein large numbers of moderately and strongly positive nuclei, in random array, were present in essentially full thickness distribution. In many fields, however, a layer of cytologically bland basal cells, with faint or no nuclear staining, was interposed between dysplastic epithelium and dermis. This study has demonstrated that proliferating cell populations in epidermal lesions can be assessed with simple, inexpensive methods. There were consistent differences between the proliferating cell populations of the various entities studied, differences that can be reasonably correlated with other known clinical, microscopic, and biologic features of the lesions. This technique should provide an interesting new avenue for study of diverse cutaneous diseases.

Measurement of proliferating cell nuclear antigen (PCNA) and its clinical application in oral cancers

The PCNA score was measured in oral squamous cell carcinoma (SCC), and its relationship to other cell proliferation markers, Ki-67 score, S-phase fraction (SPF), and AgNORs counts was investigated. The PCNA score ranged from 0.4% to 43.5% with an average value of 22.8%, the Ki-67 score ranged from 4.9% to 40% with an average of 24.1%, and the SPF ranged from 0.4% to 32.5% with an average of 12.4%, while AgNORs counts ranged from 2.53/nucleus to 7.03/nucleus with an average of 4.74/nucleus. These four parameters were closely interrelated. There was a significant difference in PCNA score between malignant and nonmalignant lesions, suggesting a difference in growth activity. The mean PCNA score decreased significantly from 20.0% to 8.0% after cancer chemotherapy. The response of cancer cells to anticancer agents may be estimated by consecutive measurement of PCNA, since the PCNA score dropped after treatment in cases showing a favorable prognosis.

Alveolar atypical hyperplasia in association with primary pulmonary adenocarcinoma: a clinicopathological study of 10 cases

BACKGROUND

A distinctive cytologically atypical lesion has been found in patients with primary adenocarcinoma of the lung. The aim of this study was to characterise the lesion and assess its role in tumour pathogenesis.

METHODS

Lung parenchyma from 175 consecutive resection specimens for primary pulmonary adenocarcinoma were examined. Foci of atypical hyperplasia were identified. Cell proliferation state and expression of S100 and carcinoembryonic antigens were evaluated by immunohistochemistry. Clinical data on cigarette smoking and occupational exposure to carcinogens were abstracted from inpatient case notes.

RESULTS

Ten cases (5.7%) with these distinctive cytologically atypical lesions were identified. The lesions showed immunohistochemical evidence of increased cell proliferation and focal carcinoembryonic antigen expression. The associated adenocarcinomas were of peripheral (parenchymal) type. There was an association with cigarette smoking and two of the 10 patients had synchronous carcinomas elsewhere in the lung.

CONCLUSION

The clinical and pathological associations of these lesions suggest that they may be important in the histogenesis of primary pulmonary adenocarcinoma.

Analysis of proliferative activity in colorectal mucosa by immunohistochemical detection of proliferating cell nuclear antigen (PCNA)

Immunohistochemical detection of proliferating cell nuclear antigen (PCNA) has been suggested as a new approach for determining proliferative activity in paraffin-embedded tissue. In a prospective study PCNA immunostaining was performed in 284 colorectal biopsies using monoclonal antibodies 19F4 (Ogata et al. 1987) and PC10 (Waseem and Lane 1990) and compared with the Ki67 method. From each site three biopsies were taken and a variety of fixation regimens for frozen and paraffin-embedded samples tested. For frozen biopsies methanol fixation at -20 degrees C proved best. In paraffin sections PCNA could be detected after methacarn fixation as well as after controled fixation at 4 degrees C in 4% paraformaldehyde for 1 h and in most biopsies routinely fixed with 10% formalin. However, the latter fixation regimens revealed additional PCNA-positive cells in the normal superficial colonic mucosal epithelium. Although the percentage of cells positive for PCNA was generally lower than for Ki67, the rates correlated in a highly significant fashion, both in frozen methanol-fixed biopsies, and in paraformaldehyde-fixed paraffin-embedded samples. PCNA immunohistochemistry revealed a similar proliferative activity in different parts of the large bowel. A higher proliferative activity was found in inflamed mucosa, adenomas, carcinomas and even in normal mucosa from patients with colorectal neoplasms. In routinely fixed biopsies, the monoclonal antibody PC10 was superior to 19F4 because of considerably less background staining. However, in the routine material only a rough estimate of the proliferative activity was possible by PCNA immunohistochemistry using these antibodies, because unpredictable numbers of non-S-phase cells were also stained.(ABSTRACT TRUNCATED AT 250 WORDS)

Proliferating cell nuclear antigen (PCNA) as a prognostic factor in non-Hodgkin's lymphoma

The prognostic value of immunoperoxidase staining for proliferating cell nuclear antigen (PCNA) was studied in a series of 140 non-Hodgkin's lymphomas with median follow-up of 9 years. Lymphomas where > 50% of cells showed positive staining for PCNA had inferior 5-year survival as compared with those with less than 50% of positive cells (57% vs 41%, P = 0.008). The presence of > 50% of positively staining cells for PCNA was strongly associated with a larger than the median size of the SPF (median, 8.3%), and high histological grade of malignancy (P < 0.0001 for both). Lymphomas with both a large percentage (> 50%) of PCNA positive cells and a larger than the median SPF had inferior outcome as compared with lymphomas where either one or both of these factors were small. Although PCNA staining was not an independent prognostic factor in a multivariate analysis, it appears to be supplementary to the SPF even if determined from old paraffin-embedded tissue material.

Epithelial proliferation in Barrett's esophagus by proliferating cell nuclear antigen immunolocalization

Proliferating cell nuclear antigen (PCNA) is an auxiliary protein to DNA polymerase delta and is an absolute requirement for cellular proliferation. Specialized-type Barrett's columnar-lined esophagus (CLE) is associated with adenocarcinomatous change. In the present study, the cellular proliferation of three histological types of CLE was assessed by semiquantitative evaluation of PCNA immunolocalization in 93 biopsy specimens from 45 patients using the murine monoclonal PC10. Statistical comparison was performed by the Mann-Whitney U test. Luminal surface cell labeling was uncommon in all histological types other than specialized CLE where 25 of the 43 biopsy specimens had at least occasional luminal surface cell labeling. Mean crypt labeling score of 4.06 for specialized type exceeded that for junctional (mean, 3.12; P < 0.001) and fundic types (mean, 1.6; P < 0.001). Gland cell PCNA staining scores for specialized-type CLE (mean, 3.18) exceeded that of junctional (mean, 1.97; P < 0.001) and fundic (mean, 1.04; P < 0.001). Summated PCNA scores for specialized-type, mean of 8.29, exceeded junctional mean score of 5.45 (P < 0.001) and fundic mean score of 2.76 (P < 0.001). PCNA immunolocalization reveals a high proportion of cells in cycle in the specialized-type CLE and expansion of the proliferative compartment, which may explain the association of specialized-type CLE with malignancy.

An assessment of the proliferative potential of 'balloon cells' in focal cortical resections performed for childhood epilepsy

Cerebral cortical dysplasia is an uncommon pathological substrate of severe intractable childhood epilepsy, sometimes treated by hemispherectomy. Neuropathological findings include abnormal gyrus formation, loss of cortical lamination, unusual giant neurons and 'balloon cells' of indeterminate histogenesis similar in appearance to neoplastic gemistocytic astrocytes. In order to investigate the proliferative potential of 'balloon cells', we used Crocker's silver impregnation technique to demonstrate nucleolar organizer regions (AgNORs) involved in cellular proliferation, together with immunohistochemical evaluation of proliferating cell nuclear antigen (PCNA) expression. Balloon cells (5.56 +/- 0.24) had significantly (P < 0.001) greater AgNOR numbers than reactive astrocytes (3.89 +/- 0.15), neurons (2.30 +/- 0.13) or giant neurons (4.26 +/- 0.20). However, when corrected for nuclear size, results showed that 'balloon cells' (0.093 +/- 0.006) had significantly (P < 0.001) fewer AgNORs/square micrometre of nuclear area than reactive astrocytes (0.225 +/- 0.016) and had significantly (P < 0.001) more AgNORs/square micrometre of nuclear area than normal (0.048 +/- 0.003) or giant neurons (0.054 +/- 0.003). On the assumption that astrocytes are typical interphase cells and that normal neurons are post-mitotic, the results suggest that 'balloon cells' are unlikely to be undergoing proliferative activity and, when adjusted for nuclear size, the number of AgNORs/unit of nuclear area is more reflective of cellular ploidy than of proliferative activity in non-neoplastic neural tissues. The virtual absence of PCNA expression by 'balloon cell' nuclei supports such an interpretation of the AgNOR results.

Proliferating cell nuclear antigen (PCNA) in atypical and malignant meningiomas

Because it is not easy to determine the tumor status of meningiomas by current diagnostic procedures, we investigated these tumors immunohistochemically using the monoclonal antibody PC 10. This antibody recognizes a fixation- and processing-resistant epitope of the proliferating cell nuclear antigen (PCNA), which is a 36-KD nuclear antigen associated with the cell cycle. We studied paraffin-embedded and formalin-fixed tissue specimens of a group of 21 atypical/malignant meningiomas together with 18 benign meningiomas. PCNA staining results were compared with the mean number of silver-stained nucleolar organizer region-associated proteins (AgNORs), tumor grading, and mitotic indices of these tumors. The percentage of PCNA-positive cells was found to range between 0.1% and 40%, irrespective of the tumor grade. When all tumors were collectively considered, no positive correlation was found between PCNA scores and histologic grading and only a weak one between PCNA score and mitotic index. A higher correlation was seen between AgNOR counts and tumor grading. Our results suggest that PCNA labeling and histologic grading seem to be independent parameters. The correlations found between AgNOR counts and tumor grading should be substantiated in further series.

Assessment of rejection in orthotopic human heart transplantation using proliferating cell nuclear antigen (PCNA) as an index of cell proliferation

Myocardial biopsies taken during the management of cardiac transplantation were stained for proliferating cell nuclear antigen (PCNA). Counts of PCNA-positive interstitial cells were compared, in retrospect, with the reported histological grade of rejection. Biopsies without rejection had negligible numbers of PCNA-positive cells. Ascending grades of rejection were paralleled by an increase in the number of PCNA-positive cells [grade 1, 13 +/- 35 (mean +/- SD); grade 2a, 38 +/- 40; grade 2b, 91 +/- 75; grade 3, 170 +/- 78]. While highly significant, in statistical terms, the overlap in the counts between different grades means that prediction of rejection from the PCNA count alone is not feasible. Biopsies graded as 0 or 1 and which immediately preceded more severe rejection episodes showed no increase in PCNA-positive cells. The majority of PCNA-positive cells are fibroblasts, although in grade 2b and 3 rejection a small population of PCNA-positive T lymphocytes occurs. PCNA staining is also seen in cardiac myocytes immediately after transplantation, during rejection episodes, and late after transplantation in the absence of rejection. The positive PCNA staining of cardiac myocytes probably reflects DNA synthesis that occurs with the shift toward polyploidy in hypertrophy.

Proliferating cell nuclear antigen and S phase fraction in endometrial stromal sarcoma

AIMS

To investigate the value of immunohistochemical staining for the cell cycle protein proliferating cell nuclear antigen (PCNA) and flow cytometric S phase fraction in determining prognosis in endometrial stromal sarcoma, graded according to mitotic count.

METHODS

Seventeen endometrial stromal sarcomas from 13 patients treated at the Royal Marsden Hospital were analysed. Serial 5 microns sections were cut for haematoxylin and eosin and immunohistochemical staining for PCNA, performed using the murine monoclonal antibody PC10. PCNA positivity was expressed as a percentage of the total number of cells (PCNA index). Flow cytometric analysis was performed on nuclei extracted from paraffin wax sections.

RESULTS

In the five patients who died of disease within five years, PCNA index varied between < 1% and 60% (mean 21%) and S phase fraction ranged from 11.3 and 20.1 (mean 13.8). Four patients who were apparently cured showed PCNA indices ranging from < 1% to 5% (mean 1.75%) and S phase fraction ranging from 1.4 to 3.5 (mean 2.3); and three patients alive with disease showed PCNA indices ranging from 1% to 15% (mean 8.6%) and S phase fraction ranging from 1.4 to 3.5 (mean 2.3). One patient who died from indolent local disease after nine years showed a PCNA of 1 or less and an S phase fraction of 0.9.

CONCLUSIONS

PCNA staining was variable and therefore not a reliable prognostic indicator, but a high PCNA index was only found in those patients dying of disease within five years. A stronger association was seen between S phase fraction and prognosis; this also correlated well with histological grade determined by mitotic count. In individual borderline cases that are between low and high grade categories, these procedures may be useful.

p53 protein in odontogenic cysts: increased expression in some odontogenic keratocysts

AIMS

To assess p53 protein expression in a range of odontogenic cysts arising in the mouth, including those of developmental and inflammatory origin.

METHODS

p53 protein was identified using the polyclonal antibody CM-1, together with a standard immunoperoxidase technique. A total of 36 cystic lesions were examined, all of which were histologically benign.

RESULTS

Expression of p53 protein was identified within the lining of five of 12 odontogenic keratocysts but was not detected in the other cystic lesions in the series.

CONCLUSIONS

This is believed to be the first report that identifies increased expression of p53 protein in benign cystic epithelium. The increased expression of p53 protein in the nucleus is usually associated with malignant disease. These findings are relevant to the management of odontogenic keratocysts which have a tendency to recur, and also to Gorlin Goltz syndrome in which keratocysts and multiple basal cell carcinomas are features.

Comparison of proliferation rates assessed using "multiblock" and conventional tissue blocks of lung carcinoma

AIMS

To compare the proliferative rates, assessed immunohistochemically, of human lung tumours using conventional paraffin wax blocks and the multitumour tissue block (MTTB) technique.

METHODS

A multiblock containing 20 lung tumours (eight adenocarcinomas, five squamous cell, five small cell and two carcinoid tumours) was constructed. Sections were also cut from the original blocks of formalin fixed, paraffin wax embedded tissue used to construct the multiblock. Sections were stained with the monoclonal antibody PC10, which recognises a proliferating cell nuclear antigen, using the three stage immunoperoxidase technique.

RESULTS

The proliferation rates of the lung tumours obtained using both techniques were, overall, significantly different (p = 0.05), although most cases showed good correlation. Some tumours displayed a high degree of intratumoral variation in PC10 staining. The degree of PC10 staining was in keeping with the known proliferative state of particular histological subtypes--that is, carcinoid tumours showed little staining and small cell carcinomas showed extensive positivity.

CONCLUSION

The MTTB technique is a less suitable means of assessing proliferation rate in lung carcinomas than conventional tissue blocks. It should be restricted to qualitative antibody studies or quantitative studies using tumours with little intratumoral variation.

p53 protein expression in central nervous system neoplasms

AIMS

To demonstrate, immunohistochemically, p53 protein expression in a selection of central nervous system tumours; to investigate the relation between p53 expression and that of the proliferation related antigen, PCNA.

METHODS

Surgical specimens from 86 central nervous system tumours were routinely fixed, paraffin wax embedded, and immunostained with a monoclonal (PAb 1801) and a policlonal antibody (CM1) p53 protein and a monoclonal antibody against PCNA (PC10). Normal brain samples obtained at necropsy and 10 surgically obtained samples of gliotic brain parenchyma were also immunostained.

RESULTS

p53 protein expression was observed in 35 of 86 brain tumours, suggesting frequent p53 gene mutation. p53 protein alterations were associated with all grades of malignancy in tumours displaying solely astrocytic differentiation, with the exception of pilocytic astrocytomas. In those showing oligodendroglial or ependymal differentiation they appeared to be restricted almost to only high grade lesions. No p53 immunoreactivity was observed in normal or gliotic brain tissue; p53 altered expression was not related to the percentage of PCNA labelled cells.

CONCLUSIONS

The use of sophisticated gene amplification techniques or highly sensitive immunohistochemical methods might be useful in distinguishing between reactive and neoplastic astrocytic lesions, and in the identification of malignant progression in other non-astrocytic glial tumours. Tumours with very similar histogenetic differentiation features might actually be a genetically heterogeneous group with possible different clinical courses.

Immunohistochemistry and proliferative activity in Lhermitte-Duclos disease

We have evaluated a recurrence of Lhermitte-Duclos disease by immunohistochemistry for Purkinje cell markers and proliferative activity (proliferating cell nuclear antigen), by electron microscopy and for DNA ploidy (image analysis). While most of the abnormal neurons in the lesion appear to be derived from granule cells, several Purkinje cell specific polyclonal and monoclonal antibodies, including L7, PEP 19 and calbindin, labeled a minor subpopulation. Staining with monoclonal antibodies to proliferating cell nuclear antigen and measuring cell DNA index and ploidy with a cell image analyzer revealed no proliferative activity. Electron microscopy findings were similar to those previously reported. In spite of its recurrence, our findings support the notion that Lhermitte-Duclos disease is malformative, not neoplastic, and that the characteristic neurons are derived predominantly but not exclusively from a non-Purkinje cell source, probably the granule cell.

Monoclonal antibody JC1: new reagent for studying cell proliferation

AIM

To characterise a newly developed mouse monoclonal antibody JC1 which recognises a nuclear antigen present in proliferating cells in normal tissues and neoplastic lesions, and which is absent in resting cells.

METHODS

The methodology was established using a representative range of frozen sections from normal tissues and from certain tumours which were immunostained with antibodies Ki67 and JC1. The molecular weight of the antigen recognised by JC1 was obtained by western blot analysis and this was compared with that of Ki67. IM-9 cell lysates containing Ki67 derived plasmids were also tested with JC1 antibody.

RESULTS

Biochemical investigation indicated that the antigen recognised by JC1 gives two molecular weight bands of 212 and 123 kilodaltons, which is distinct from the well characterised anti-proliferation monoclonal antibody Ki67 (395-345 kilodaltons). In addition recombinant Ki67 protein is not recognised by JC1. Immunohistological reactivity was seen in areas known to contain numerous proliferating cells such as lymphoid germinal centres, splenic white matter, cortical thymocytes and undifferentiated spermatogonia. In tumours many cells from adenocarcinomas, oat cell carcinomas, squamous cell carcinomas of lung, and seminomas were labelled by JC1 with a distribution and proportion similar to that seen with Ki67. In normal tissues the only apparent difference was in testis where JC1 stained a considerably greater number of cells than Ki67. In all cases studied the new antibody showed nuclear reactivity only. JC1 did not show any cytoplasmic crossreactivity with squamous cells as is frequently seen with Ki67.

CONCLUSION

Antibody JC1, which recognises a nuclear antigen present in proliferating cells, should provide a useful adjunct to Ki67 as a marker of proliferation especially in those cases such as squamous cell carcinomas where a Ki67 index cannot be determined.

Delay in fixation does not affect the immunoreactivity of proliferating cell nuclear antigen (PCNA)

The effect of delayed fixation on the immunoreactivity of proliferating cell nuclear antigen (PCNA) was investigated using eight breast carcinomas. Topologically shuffled samples of each tumour were immersed in fixative at times of 0.5, 1, 2, 4, 6, 18, and 24 h after surgical removal. In addition to a PCNA index (percentage of positive cells per 1200 tumour cells), a semi-quantitative PCNA grading system was used, based on estimates of more than or less than 50 per cent of positive tumour cells at each time interval. The PCNA index of six tumours increased by a mean of 10 per cent with a fixation delay of 24 h. The PCNA grade of all eight tumours showed no change with delayed fixation.

Production of a monoclonal antibody (IND.64) identifying a cell cycle-associated antigen using spleen cells from nude mice bearing Ichikawa tumour

Using spleen cells from athymic nude mice grafted with Ichikawa tumour, we have generated the monoclonal antibody IND.64, which detects a proliferation-associated nuclear antigen. Immunoblotting analysis with IND.64 showed a double band with apparent molecular weights of 395 and 345 kD. In normal human tissues, the antigen detected by IND.64 was expressed only by the nuclei of proliferating cells, such as germinal centre cells of reactive lymph nodes, cortical thymocytes, the basal layer of the skin, and proliferative compartments of the stomach, small intestine, and colon. IND.64 did not react with cells known to be non-proliferative or to show only a low turnover, such as cells of the kidney, liver, smooth muscle, cardiac muscle, and brain. The expression of this antigen during the cell cycle was determined using two approaches: IND.64 immunostaining of synchronized adult bovine aortic endothelial cells and flow cytometric analysis of double-labelled PHA-stimulated peripheral mononuclear blood leucocytes with a DNA marker and IND.64. The antigen recognized by IND.64 was found to appear in the late G1 phase, and persisted in phases S, G2, and M, but was absent in the G0 and early G1 phases. IND.64 was further investigated in different tumour types to evaluate the correlation between the percentage of IND.64-positive cells (IND.64 index) and the histological grade. In non-Hodgkin's lymphomas, an excellent correlation was found between the percentage of IND.64-positive cells and the cytomorphological grade. In nodular sclerosis and mixed cellularity Hodgkin's disease, a high number of Reed-Sternberg cells were positive with IND.64. The non-lymphoid neoplasms investigated showed a variable percentage of positive cells. IND.64 appears to be a promising tissue marker to complement the evaluation of prognosis in human cancer.

The expression of proliferating cell nuclear antigen in paraffin sections of peripheral, node-negative non-small cell lung cancer

Cell proliferation of 40 peripheral, node-negative non-small cell lung cancers (NSCLC) treated with surgery alone was investigated by immunohistochemical analysis with the monoclonal antibody (MoAb) PC10, which recognizes a proliferating cell nuclear antigen (PCNA) in formalin-fixed and paraffin-embedded material. Results were correlated with DNA ploidy and S-phase fraction (SPF) analyzed by DNA flow cytometric study. Mitotic count (MC) was analyzed by light microscopic study and histopathologic features. PCNA immunoreactivity was seen in all samples and confined to the nuclei of cancer, but not to the surrounding, tumor-negative cells; its frequency ranged from 0-70% (median, 15%), and tumors expressed either a low (0-25%, n = 25) or intermediate (26-75%, n = 15) proliferative activity. There was no relationship between PCNA immunoreactivity and tumor stage or among size, histologic type, and mitotic count (MC). Tumors with intratumoral blood vessel invasion (BVI) showed a significantly higher (P less than 0.005) PCNA immunoreactivity than BVI-negative tumors. PCNA scores were significantly higher (P less than 0.005) in DNA aneuploid (n = 22) than in DNA diploid (n = 18) tumors and correlated significantly with the SPF of DNA aneuploid tumors (r = 0.825, P less than 0.0001), but not with diploid tumors (r = 0.002, P = 0.9). Intermediate proliferating tumors had a significantly higher (P less than 0.01) MC than their counterparts. In univariate analysis, significant predictors of survival were tumor classification (T1 versus T2), tumor size (less than or equal to 2.6 cm versus more than 2.6 cm), BVI (BVI-negative versus BVI-positive), MC (less than or equal to 8 versus more than 8), and PCNA immunoreactivity (low versus intermediate). DNA ploidy and SPF did not influence survival significantly. Only PCNA immunoreactivity retained its independent level of significance (P = 0.02) by multivariate analysis. It was concluded that PCNA immunostaining is a simple and clinically useful method for estimating cell proliferation in formalin-fixed, paraffin-embedded tissue of resected peripheral, node-negative NSCLC.

Prognostic significance of the PC10 index as a prospective assay for cervical cancer treated with radiation therapy alone

The monoclonal antibody PC10 recognizes proliferating cell nuclear antigen (PCNA) in conventionally fixed and processed histologic materials. Formaldehyde-fixed and paraffin-embedded specimens taken from 194 patients with Stage III squamous cell carcinoma of the cervix treated with radiation therapy alone were investigated for PC10 positivity using immunohistochemical methods. A few squamous epithelial cells in the basal layer and the deepest zone of the prickle cell layer were positive for PC10. Cancer cells also were positive for PC10, showing a diffuse or granular nuclear staining pattern. The multiple logistic regression model analysis and the Kaplan-Meier method indicate that a strong correlation exists between the PC10 index and prognosis (P less than 0.001). Thus, the PC10 index may be a predictive indicator for the prognosis of patients with squamous cell carcinoma of the cervix treated with radiation therapy alone.