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

P53 expression in spontaneous and estradiol-induced endometrial hyperplasia during menopause

OBJECTIVE

To determine the percentage of endometrial hyperplasia positive for p53 expression in both spontaneously occurring cases or following the use of unopposed estradiol.

METHODS

Fifty-four postmenopausal patients with endometrial hyperplasia diagnosed by endometrial biopsy and hysteroscopy were recruited to this study. Thirty-three patients had used unopposed estradiol for periods of time from 1 to 3 years. P53 expression was detected in paraffin-embedded endometrial specimens by immunohistochemical methods.

RESULTS

The percentage of endometrial hyperplasia positive for p53 expression was significantly greater in spontaneously occurring hyperplasia than in cases induced by the unopposed use of estradiol.

CONCLUSION

Endometrial hyperplasia caused by the unopposed use of estradiol during menopause probably harbors fewer genomic errors than those cases occurring spontaneously.

Cell cycle analysis and detection of proliferative cell nuclear antigen of the endometrium after hormone replacement therapy

BACKGROUND

To understand the effect of sequential combined hormone replacement therapy (HRT) on the postmenopausal endometrium.

METHODS

Sonographic endometrial thickness, endometrial histopathology, flow cytometric cell cycle analysis and the level of proliferative cell nuclear antigen (PCNA) were studied.

RESULTS

One hundred and thirty-eight postmenopausal women were enrolled in this study. Among which, 97 women had their endometrium being adequately obtained; the most frequent type of histopathology was normal endometrium (91.8%). Endometrial hyperplasia was found in seven patients (7.2%), including typical simple hyperplasia (n=1, 1%), focal simple hyperplasia (n=5, 5.2%) and complex hyperplasia without atypia (n=1, 1%). The proliferative fractions (PF; S plus G2-M phase) of cells from normal and hyperplastic endometrium of menopausal women after HRT were 8.18 and 8.95%, respectively, which were lower than those from 29 premenopausal women without HRT. The level of PCNA of normal and hyperplastic endometrium in postmenopausal women after HRT was about 80 and 84%, respectively, of that from premenopausal endometrium.

CONCLUSIONS

Our study showed the PF of the cell cycle and the level of PCNA were not increased in the menopausal endometrium under HRT as compared to the premenopausal controls.

Computerized image analysis of p53 and proliferating cell nuclear antigen expression in benign, hyperplastic, and malignant endometrium

CONTEXT

The endometrium is an intrinsically dynamic tissue with great capability for regeneration and proliferation; consequently, there is some overlap between features seen in benign, premalignant, and malignant lesions. This leads to marked intrabiopsy, interbiopsy, and interobserver variability.

OBJECTIVE

We studied the specificity and sensitivity of computerized image analysis of molecular markers to evaluate its potential use as a diagnostic tool.

DESIGN

Specimens from 100 patients were examined and the following histologic diagnoses were assigned: proliferative endometrium (n = 10), secretory endometrium (n = 10), endometrial hyperplasia (n = 40; 30 with no atypia, 10 with atypia), and carcinoma (n = 40; 20 endometrioid, 10 serous, and 10 clear cell). All cases were evaluated immunohistochemically for p53 and proliferating cell nuclear antigen (PCNA) expression. Computerized image analysis was performed with a CAS 200 digital analyzer.

RESULTS

Expression of p53 was found only in carcinomas (65%) and endometrial hyperplasia with atypia (30%). Expression of p53 was higher in the poor prognostic categories (serous carcinoma and clear cell carcinoma) than in endometrioid carcinoma. In endometrioid carcinoma, p53 expression correlated with grade. Proliferating cell nuclear antigen showed a similar pattern of results to p53 in the various carcinoma subtypes and endometrioid carcinoma grades. Endometrial hyperplasia PCNA values were the lowest among all the groups. Both carcinomas and proliferative endometrium showed higher glandular and stromal PCNA values, significantly different from endometrial hyperplasia with atypia. In proliferative endometrium, stromal PCNA was the highest among all of the groups. The p53 and PCNA results correlated with each other for carcinoma.

CONCLUSIONS

Computerized image analysis correlates well with the established morphologic groups of endometrial pathology and yields results consistent with previous studies. Owing to its higher degree of sensitivity, computerized image analysis is of potential use in cases of diagnostic dilemmas and can help objectively allocate the case in the correct category (e.g., proliferative endometrium vs. endometrial hyperplasia, endometrial hyperplasia with atypia vs. endometrioid carcinoma). It is particularly useful in the evaluation of stromal changes.

MIB-1 in endometrial carcinoma: prognostic significance with 5-year follow-up

OBJECTIVE

MIB-1, a monoclonal antibody to the Ki-67 antigen, has presumptively been shown to be predictive of recurrent disease in patients with endometrial cancer. In order to more conclusively establish whether MIB-1 staining can be used as a prognostic indicator of recurrent disease or survival, a larger group of patients with a minimum follow-up of 5 years was analyzed.

METHODS

The tumors from 147 consecutive patients receiving primary surgical therapy for endometrial carcinoma were evaluated with the MIB-1 monoclonal antibody. Proliferation index was quantified by image analysis. Patients were followed for a minimum of 60 months. In addition to MIB-1 staining, histologic type, stage, grade, depth of invasion, lymphovascular space invasion, and peritoneal cytology were evaluated as prognostic indicators.

RESULTS

Twenty-five of 147 patients died during the study period. MIB-1 staining was not significantly elevated in advanced (stage II, III, and IV) as opposed to early (stage I) carcinomas (P = 0.38). In patients whose tumor MIB-1 staining was less than 33.0%, no deaths occurred. By multivariate analysis, only MIB-1 staining (P < 0.001), FIGO stage (P = 0.005), and LVI (P = 0.005) were shown to be independent prognostic indicators predictive of survival.

CONCLUSION

In this series of 147 consecutive patients with endometrial carcinoma, the monoclonal antibody MIB-1 was shown to be an independent prognostic indicator of 5-year survival. This follow-up further validates the previous work regarding the significance and potential usefulness of MIB-1 as a prognostic indicator.

Prognostic significance of progesterone receptor immunohistochemistry for lymph node metastases in endometrial carcinoma

OBJECTIVE

The aim of this study was to determine whether progesterone receptor (PR), estrogen receptor (ER), p53 protein, and proliferating cell nuclear antigen (PCNA) expression constitute independent prognostic factors for lymph node metastases in endometrial carcinoma using immunohistochemical techniques on hysterectomy and biopsy specimens.

METHODS

We evaluated the correlation between lymph node metastases and PR/ER immunohistochemistry, p53/PCNA expression, age, tumor grade, myometrial tumor invasion, cervical involvement, and ovarian metastases in a series of 99 cases of primary endometrial carcinoma surgically staged with systemic pelvic lymphadenectomy and para-aortic lymph node biopsy.

RESULTS

Lymph node metastases from endometrial carcinoma were statistically correlated with negative PR immunohistochemistry (P = 0.001), intense p53 expression (66% or more of the tumor cells stained, P = 0.003), deep myometrial tumor invasion (greater than one-half, P = 0.001), and cervical involvement (P = 0.001). Tumor grade showed borderline statistical significance for lymph node metastases (P = 0.058). On multivariate analysis, negative PR, intense p53 expression, and cervical involvement were significant prognostic variables for lymph node metastases (P = 0.0001, 0.0023, and 0.002, respectively). Immunohistochemical study indicated that the PR status on preoperative biopsy specimens and hysterectomy specimens was in good agreement, but p53 status was not. Age, ovarian metastases, ER immunohistochemistry, and PCNA expression were not significantly related to lymph node metastases.

CONCLUSION

PR immunohistochemistry appeared to be the most powerful prognostic factor associated with lymph node metastases in endometrial carcinoma, independent of other clinicopathological parameters.

p53, PCNA and Ki-67 expression in oral squamous cell carcinomas: the vagaries of fixation and microwave enhancement of immunocytochemistry

Proliferation markers are widely used as indicators of tumour progression and aggression. Fixation and antigen retrieval methods may enhance the immunocytochemical sensitivity of these markers but may also lead to loss of specificity. As these methods are often used quantitatively, standardisation of internal and external methodology is paramount. This study aimed to compare the effects of alcohol and formalin fixation and of microwaving on the immunocytochemical demonstration of p53, PCNA and Ki-67 in oral squamous cell carcinoma using duplicate tissue blocks from 24 cases. Both qualitative and quantitative differences in antigen expression were revealed. Whilst alcohol fixation alone at least maintained and usually increased the strength of positive staining, microwaving alcohol-fixed sections often gave rise to non-specific staining. p53 staining following microwave enhancement of alcohol-fixed tissue showed a significant incidence of conversion of negative results to positive and of positive staining in unexpected tissue components. Alcohol fixation increased the sensitivity of PCNA detection with a far less dramatic loss of specificity. The results emphasise the need for careful standardisation of immunocytochemical methods, particularly when used quantitatively and for inter-laboratory comparisons.

Correlation of proliferation indices, apoptosis, and related oncogene expression (bcl-2 and c-erbB-2) and p53 in proliferative, hyperplastic, and malignant endometrium

BACKGROUND

The various morphological groupings of endometrial pathology are often difficult to distinguish from each other. The endometrium is an actively proliferating tissue and there is an overlap in cell proliferation fraction (CPF) between benign proliferative endometrium (BPE) and endometrial carcinoma (EC). Apoptosis in benign cycling endometrium is related to the menstrual cycle. In this study we evaluated CPF, apoptosis, and oncogenes that relate to cell turnover (bcl-2, p53, and c-erbB-2) in the spectrum of endometrial pathology.

METHODS

We examined a total of 64 cases consisting of 10 cases of BPE, 18 cases of simple endometrial hyperplasia (SEH), 18 cases of complex hyperplasia (CEH; including eight cases with atypical hyperplasia), and 18 cases of EC, FIGO grade 1. CPF was measured by the mitotic index (MI) and by the percentage of Ki-67 positive nuclei (Ki-67 index). Apoptotic index (AI) was determined on hematoxylin and eosin sections.

RESULTS

MI was 2.48% in BPE, 0.65% in SEH, 0.6% in CEH, and 0.91% in EC (P < .00001). Ki-67 index was 38.44%, 16.4%, 23.25%, and 31.7% respectively (P < .00001). AI was 1.17%, 2.2%, 2.57%, and 3.31% respectively (P = .02). The AI/MI and AI/Ki-67 ratios were lowest in BPE and highest in SEH (P = .007). All cases of BPE, 84% of SEH cases, 77% of CEH cases, and 88% of EC cases displayed cytoplasmic and/or nuclear bcl-2 expression. Cytoplasmic bcl-2 expression increased from BPE to SEH, whereas it decreased in CEH and EC with emergence of only nuclear expression. Of the EC cases, 38.8% showed intense nuclear bcl-2 reactivity and a significantly higher Ki-67 index than cases with cytoplasmic expression (P = .01). No p53 or c-erbB-2 expression was seen in either BPE or EH. Of the EC cases, 50% were positive for p53 whereas 30% were positive for c-erbB-2. C-erbB-2-positive cases had a significantly higher Ki-67 index and AI than negative cases (P = .02). Cases of EC with p53 expression also had significantly higher AI (P = .01).

CONCLUSIONS

In actively proliferating tissues like endometrium, CPF does not correlate with progression to malignancy. In contrast, AI and derived AI/CPF ratios are better indicators of progression. The expression of p53, c-erbB-2, and nuclear bcl-2 in EC correlate with higher cell turnover indices (CPF and AI).

Recent advances in the histopathology and molecular pathology of carcinoma of the endometrium

Endometrial carcinoma is the commonest malignancy of the female genital tract. The pathogenesis is complex and at least three pathogenetic subtypes exist with different prognostic implications. The molecular events involved remain poorly defined but several genes are involved and mutations of tp53, WAF1/CIP1, PTEN, bcl-2 and c-erbB-2 have been implicated. Although care is needed in interpreting the results, the majority of these mutations can be detected immunohistochemically and therefore have the potential to aid the pathologist and surgeon in assessing the prognosis of a tumour. However, for the time being, no molecular marker is as valuable in determining prognosis as conventional parameters such as tumour type, grade and vascular space involvement.

Correlation of growth fraction by Ki-67 and proliferating cell nuclear antigen (PCNA) immunohistochemistry with histopathological parameters and prognosis in primary breast carcinomas

The immunoreactivity for Ki-67 and PCNA was investigated in 487 patients with primary breast carcinomas using MIB-1 (Immunotech, France) and PC-10 (DAKO, Denmark) as primary antibodies. Formalin-fixed and paraffin-embedded tissue sections were used. The immunoreactivity for Ki-67 and PCNA was found to be independent of the length of fixation if the sections were pretreated in a microwave oven in citrate buffer and distilled water, respectively. The immunostaining was evaluated semiquantitatively. High Ki-67 score (more than 1% positive tumour cells) and PCNA over-expression (more than 25% positive tumour cells) were correlated with clinicopathological parameters such as large tumour size, high histological grade (poor differentiation), and absence of steroid hormone receptors, which are parameters of an aggressive phenotype of the tumour. In univariate analysis of survival data, both Ki-67 and PCNA were parameters of a poor overall survival in both lymph node-positive and -negative patients. In multivariate anlaysis using a Cox model stratified by nodal status, Ki-67 and PCNA failed to be of prognostic significance whereas classical histopathological parameters such as tumour size and histological grade turned out to be of independent prognostic significance in both lymph node-positive and -negative patients, while progesterone receptors were of independent prognostic significance only in lymph node-positive patients.

Diethylstilbestrol-induced immortalization of human endometrial cells: alterations in p53 and estrogen receptor

Carcinogenesis is a process requiring multiple steps. Immortalization is one step in this process and may be rate limiting. To further our understanding of estrogen-induced carcinogenesis, we evaluated diethylstilbestrol (DES)-induced immortalization of human endometrial stromal cells. This was achieved by assessing at the restrictive temperature the colony-forming efficiency of cells that were conditionally immortalized with a temperature-sensitive simian virus 40 large T antigen. Treatment with DES for 1 wk did not increase the immortalization frequency; however, cultures that were treated for 20 wk had a twofold increase in immortalization frequency, and continued treatment for a total of 44 wk produced a threefold increase in immortalization frequency that was dose dependent. DES-treated restrictive temperature variants (RTVs) but not spontaneous RTVs lost the temperature-sensitive phenotype. DES-RTVs also had a shorter doubling time than spontaneous RTVs did. p53 expression was increased in DES-RTVs, and its localization within the cell was altered. Conversely, expression of the estrogen receptor was decreased in DES-immortalized cells. These changes in gene expression often occur in estrogen-related malignancies, and our results are consistent with a causal role for estrogens in these p53 and the estrogen receptor alterations. Immortalization of human cells may be analogous to initiation of rodent cells, and our results suggest that estrogen-induced alterations in p53 or other genes that regulate life span could contribute to estrogen-induced initiation.

Expression of proliferating cell nuclear antigen in premalignant lesions of the larynx

PURPOSE

This study was performed to 1) evaluate the proliferative activity in premalignancies of the larynx by immunostaining for proliferating cell nuclear antigen (PCNA), 2) to examine the relationship between PCNA expression and histological diagnosis and 3) to evaluate clinical values of PCNA immunostaining.

MATERIALS AND METHODS

The percentage of PCNA-positive nuclei (PCNA index) and their highest location (PCNA grade) were evaluated in 44 specimens of premalignant lesions, 7 premalignant lesions near carcinomas, 9 normal epithelium, and 12 early invasive carcinomas of the larynx. Follow-up was conducted.

RESULTS

The mean of PCNA indices in premalignancies was significantly higher than in normal epithelium but lower than in early invasive carcinomas. PCNA index had no apparent correlation with the histological diagnosis, but in the same case, the higher degree of dysplasia showed higher PCNA index. PCNA grade showed significant correlation with the histological diagnosis. Cases with higher PCNA expression showed higher percentages of recurrence and cancerization. Premalignant lesions near carcinomas presented significantly high PCNA expression.

CONCLUSIONS

The proliferative activity in premalignancies of the larynx is higher than in normal epithelium and lower than in carcinomas. It differs from case to case, but in the same case the higher degree of dysplasia possesses higher proliferative activity. Dysplasia is associated with abnormal proliferation pattern. Special attention should be paid to those with abnormal proliferation patterns as well as high proliferative activity. PCNA immunostaining is of some referential value in predicting clinical outcome and guiding to make an early diagnosis of malignancy.

p53 immunoreactivity and mutation of the p53 gene in smooth muscle tumours of the uterine corpus

Mutation and overexpression of p53 have been described in uterine malignant mixed Müllerian tumours and in endometrial adenocarcinoma, where it has been associated with a poor prognosis. This study examines p53 expression and mutation of the p53 gene in benign and malignant smooth muscle tumours of the uterine corpus. p53 expression was evaluated by immunohistochemistry in formalin-fixed, paraffin-embedded tissue from 23 leiomyosarcomas, 10 tumours of uncertain malignant potential (TUMPs), and 18 leiomyomas. Single-stranded conformational polymorphism, (SSCP) analysis of exons 5-8 of the p53 gene was performed on 13 leiomyosarcomas, nine TUMPs, and eight leiomyomas. With microwave antigen retrieval, p53 immunoreactivity was seen in 13/23 microwave treatment, staining was abolished in three leiomyosarcomas, all immunoreactive TUMPs, and the single positive leiomyoma. SSCP analysis revealed mutation in three leiomyosarcomas. There was one mutation in exon 5 in a case with positive immunohistochemistry. Two cases with negative staining showed mutation, one in exon 7 and one in exon 8. Mutation was present in exon 7 in 4/9 and in exon 6 in 1/9 TUMPs. All of these cases showed positive immunohistochemistry. There was no significant difference in outcome between cases with and without positive immunohistochemistry. p53 expression is seen in a significant proportion of uterine leiomyosarcomas. Microwave antigen retrieval increases the proportion of positive cases and also results in positive staining in TUMPs. Mutation of the p53 gene occurs in only a minority of leiomyosarcomas and in a significant proportion of TUMPs. Positive immunohistochemistry does not, however, correlate with the presence of mutation and other factors may be responsible for p53 detection in many cases.

p53 protein expression and nuclear DNA content in breast intraductal proliferations

Immunohistochemical analysis of the p53 gene protein and cytometric assessment of nuclear DNA were performed in a series of 51 cases of intraductal breast proliferation. The series included 22 cases of intraductal hyperplasia without atypia, 6 cases of intraductal hyperplasia with atypia, and 23 cases of pure intraductal carcinoma. Expression of p53 protein was detected in one case of intraductal hyperplasia without atypia (4.5 per cent), one case of intraductal hyperplasia with atypia (16.6 per cent) and six cases of intraductal carcinoma (26.0 per cent). No significant correlation was observed between p53 expression and histological subtype of intraductal carcinoma. Aneuploidy was demonstrated in two cases of intraductal hyperplasia with atypia (33.3 per cent) and in 18 cases of intraductal carcinoma (78.2 per cent). All cases of intraductal hyperplasia without atypia were euploid. No significant association was observed between p53 protein expression and ploidy in intraductal hyperplasia. The only case of intraductal hyperplasia without atypia positive for p53 was euploid, whereas the only p53-positive case of intraductal hyperplasia with atypia was aneuploid. Among the intraductal carcinomas, only the aneuploid cases showed positivity for p53, regardless of histological subtype. The results suggest that some of the changes observed in invasive breast carcinoma, such as p53 expression and aneuploidy, are already present in breast intraductal proliferation, especially in areas with atypia and in intraductal carcinoma. The expression of p53 in breast intraductal proliferation may reflect the acquisition of p53 gene mutations in cells unable adequately to repair DNA damage, with genomic instability which would lead to clonal expansion and putative evolution to invasive disease.

TP53 gene mutations and protein accumulation in primary vaginal carcinomas

Primary carcinomas from 46 patients were screened for TP53 alterations. Immunohistochemistry demonstrated nuclear TP53 protein accumulation in 22 (48%) cases using the polyclonal CM1 antiserum, whereas 15 (33%) cases showed positive nuclear staining with the mononuclear antibody PAb 1801. Constant denaturant gel electrophoresis (CDGE) was used to screen 27 of the vaginal carcinomas for mutations in the conserved regions of the TP53 gene (exons 5-8). Six of these tumours (22%) contained mutations: four were found in exon 5 and two in exon 8. A total of 50% of the primary vaginal carcinomas carried a TP53 alteration. These results indicate that TP53 abnormalities may be involved in the development of these tumours. However, there was no significant association between TP53 abnormalities and survival.

PCNA-immunoreactivity in the uterus of rats after treatment with the antiestrogen tamoxifen

We used an antibody to the proliferating cell nuclear antigen (PCNA) to investigate the effect of the long-term administration of tamoxifen on proliferative activity in the uterus of mature rats. Untreated cycling and ovariectomized rats served as controls. The PCNA labelling indices (PI) and the mitotic indices (MI) were estimated for the luminal and glandular epithelium and for the stromal fibroblasts. A strong correlation was found for PI and MI in the luminal and in the glandular epithelium, and a lower, but also significant correlation, for the endometrial stroma cells. Tamoxifen treatment decreased the PI of the luminal epithelial cells and of the stroma as much as ovariectomy. In both of these groups, the proportion of anti-PCNA positive cells in the glandular epithelium was significantly higher than in the luminal epithelium. These data indicate that tamoxifen has a strong antiproliferative effect on the uterus of mature rats, and that this antiestrogenic action is cell type specific.