Monoclonal antibody Ki-67 defined growth fraction in benign prostatic hyperplasia and prostatic cancer

Growth fractions were assessed immunohistochemically in prostatic tissues with benign glandular hyperplasia (BPH) and in specimens of prostatic cancer using the monoclonal antibody Ki-67. This antibody is specific for a proliferation-associated nuclear antigen. In BPH tissues about 0.3% of nuclei of epithelial cells was reactive with Ki-67. The Ki-67 positive nuclei were distributed equally among the basal and luminal cells of the hyperplastic prostatic acini. In prostatic cancer the Ki-67 defined growth fraction ranged from 0.4% to 9.1% (mean value 2.9%). Cancers with a cribriform growth pattern and tumors composed of solid areas of undifferentiated cancer cells showed the highest growth fraction (average values 4.0%, respectively 7.6%). The investigated four tumors composed of undifferentiated solitary tumor cells with diffuse infiltration of the stroma demonstrated an unexpectedly low growth activity (average 1.2%). In cancers with a glandular growth pattern the Ki-67 defined growth fraction of tumor cells varied from 2.2% to 5%. Compared with other epithelial tumors these values are low, but they are in agreement with the earlier findings on prostatic cancer obtained with 3H-thymidine labeling and bromodeoxyuridine incorporation. The observed variation in the level of Ki-67 defined growth activity partly related to the histological tumor pattern suggests that Ki-67 labeling may serve as a prognostic factor additional to the current histopathological grading criteria of prostatic cancer.     

Determination of Ki-67 defined growth fraction by monoclonal antibody MIB-i in formalin-fixed,paraffin-embedded prostatic cancer tissues

The applicability of MIB-1, a monoclonal antibody directed against the Ki-67 antigen, was studied in the PC-82 and LNCaP prostatic tumor models at various levels of proliferative activity. Statistically significant correlations were found in LNCaP cultures between Ki-67 and MIB-1 scores (r = 0.84, P < 0.001), and in PC-82 tumors between MIB-1 scores and paraffin tissue Ki-67 (pKi-67) (r = 0.90, P < 0.001), frozen tissue Ki-67 (fKi-67) (r = 0.86, P < 0.001), and BrdU uptake (r = 0.70, P < 0.001), respectively. pKi-67 scores were double the fKi-67 scores, which may be due to methodological differences. MIB-1 scores exceeded both the fKi-67 and pKi-67 scores. The affinity of MIB-1 for the antigen is much higher than the affinity of Ki-67, which may explain the differences. MIB-1 is a promising means of evaluating the presence of only minute amounts of the Ki-67 antigen in paraffin-embedded human tumor material, especially in relatively slowly growing tumors. © 1995 Wiley-Liss, Inc.     

Application of the monoclonal antibody Ki-67 on prostate biopsies to assess the fraction of human prostatic carcinoma.

The feasibility of using the monoclonal antibody Ki-67 as a proliferation marker in human prostatic carcinoma was studied on aspiration and core biopsy specimens obtained from 50 patients suspected of having prostate cancer. In 32 prostatic adenocarcinomas the Ki-67 index varied from 0.3 to 13.3% (mean 4.3) in cytological smears and from 0.8 to 17.8% (mean 5.1) in frozen sections from histological core biopsies. No significant correlation between the percentage of cells positive for Ki-67 and the histological tumor differentiation could be established. In 18 patients with benign prostatic hyperplasia the Ki-67 index varied from 0 to 3.0% (mean 1.2) and from 0 to 3.8% (mean 1.4) in cytological and histological material, respectively. The differences in the observed Ki-67 index between benign and malignant prostatic tissues are of statistical (p less than 0.001) and of clinical significance. Nine patients who underwent endocrine treatment or radiotherapy entered a followup protocol in which the Ki-67 staining procedure was applied to periodically obtained cytological aspiration biopsies. During month 1 after the start of therapy a statistically significant (p less than 0.05) decrease in the Ki-67 index to 58% of the initial values was found, while at 2 and 3 months the proliferative fraction showed a further decrease to 27 and 7%, respectively. As a marker, the monoclonal antibody Ki-67 was shown to provide a reliable method to estimate the proliferative cell fraction of human prostate cancer.     

Identification of proliferating cells in human gliomas using the monoclonal antibody Ki-67

Ki-67 is a monoclonal antibody directed against a nuclear antigen present only in proliferating cells in the G1, S, G2, and M phases of the cell cycle. Fifty-one frozen glioma specimens were stained with Ki-67 using the avidin-biotin immunoperoxidase system. For each tumor, six different randomly selected fields were examined. The percentage of Ki-67-positive cells in the total number of cells in the five fields counted with counterstaining has been calculated. The areas of necrosis and the vascular endothelial cells when they were distinguishable were not included in the calculation. The indices determined on this material ranged from 0% to 4.5% (mean, 1.0; SD, 1.5) for 16 low grade astrocytomas; from 0.7% to 7.4% (mean, 3.5; SD, 2.2) for 8 anaplastic astrocytomas; and from 1.7% to 32.2% (mean, 11.1; SD, 8.2) for 27 glioblastomas. The differences among the means of each group are statistically significant. Five patients with malignant gliomas with an index of less than 2.5 had survival times of more than 40 weeks. These results show that the Ki-67 index of proliferating cells in human gliomas correlates with the usual histological classification of these tumors. There is a potential interest in using this technique in routine histopathology because it is simple and more rapid than the classic methods of evaluation of proliferating cells.     

Assessment of tumor cell kinetics by monoclonal antibody Ki-67

The expression of Ki-67 antigen in 71 patients with advanced gastric cancer was studied by immunohistochemical technique. Immunohistochemical staining with Ki-67 produced clear labeling of a portion of tumor cell nuclei, and the nucleoli stained intensely. The Ki-67 labeling rates of the 71 specimens ranged from 7.7 to 70.5% (mean: 29.2%; standard deviation: 12.9%). There was no significant association between Ki-67 labeling rates and macroscopic type, peritoneal metastasis, or serosal invasion. The tumors showing high Ki-67 labeling rates (greater than 25%) are more likely to have liver metastasis and lymph node involvement. Larger tumors, with a diameter greater than 6 cm, more frequently showed high Ki-67 labelling rate than those with a diameter less than 6 cm. When the Ki-67 labeling rate and 9 clinicopathologic parameters, as conventional prognostic factors, were entered simultaneously into the regression model, nodal status and Ki-67 labeling rate emerged as independent prognostic factors. These results indicate that the in situ determination of the growth fraction by Ki-67 antibody may be a reliable prognostic marker of advanced gastric cancer.     

Expression of Ki-67 antigen using monoclonal antibody MIB-1 in children with post-streptococcal glomerulonephritis

We investigated the expression of Ki-67 antigen using monoclonal antibody MIB-1 in glomeruli and renal tubules of 21 children (18 males, 3 females) with post-streptococcal glomerulonephritis (PSGN). Patients were divided into two groups of active and convalescent phases. The active group (n=13) comprised those patients with clinical manifestations of the acute nephritic syndrome consisting of edema, hypertension, hematuria, and oliguria or those in whom percutaneous renal biopsy was performed within 4 weeks of onset of the symptoms of PSGN and those with serum C3 levels below 55 mg/dl at the time of biopsy. MIB-1 expression was considered positive when staining of endocapillary cells was observed. Of the 21 biopsies, expression of MIB-1 in glomeruli and renal tubules was observed in 14 cases (63.6%) and 20 cases (95.7%), respectively. The expression of MIB-1 in glomeruli of patients with active disease (11/13, 84.6%) was significantly higher than that of the convalescent group (2/8, 25%) (P=0.018). The cellularity in the glomeruli was more severe in the active group than the convalescent group (P=0.0475). There was a significant difference of neutrophilic infiltration in glomeruli between the active group and the convalescent group (P=0.0117). However, glomerular MIB-1 expression did not correlate with the degree of immunofluorescence, the number of neutrophils in the glomeruli on light microscopy, and the presence of subepithelial dense deposits on electron microscopy. There was no significant correlation between MIB-1 and serum C3 level. There was no significant correlation between glomerular MIB-1 expression and creatinine clearance (r=–0.180, P=0.556) or 24-h urinary protein excretion (r=0.434, P=0.137). Our results suggest that the expression of MIB-1 in glomeruli in the active phase in PSGN was higher than in the convalescent phase and expression of glomerular MIB-1 appears to be related to glomerular endocapillary proliferation with exudative lesions in children with PSGN. Received: 20 October 1998 / Revised: 27 July 1999 / Accepted: 30 July 1999     

Proliferation activity in pituitary adenomas: measurement by monoclonal antibody Ki-67

The monoclonal antibody (MAb) Ki-67 detects a nuclear antigen expressed by proliferating cells during the entire cell cycle. In contrast to conventional histological techniques, the use of MAb Ki-67 on frozen sections or cytological smear preparations allows direct determination of the growth rate of tumors routinely. Sixty-two pituitary adenomas were investigated by use of the MAb Ki-67 in a two-step avidin-biotin-peroxidase complex technique. The proliferation activity ranged from 0.1 to 2.8%. There was no significant difference between the proliferation and hormonal state of the adenomas. Adenomas for which there was histological evidence of dural infiltration, however, showed a statistically significant higher proliferation activity (P less than 0.05) compared to noninvasive adenomas.     

Clinical growth rate of acoustic schwannomas: correlation with the growth fraction as defined by the monoclonal antibody ki-67

The growth rate of acoustic tumors, although slow, varies widely. There may be a continuous spectrum or distinct groups of tumor growth rates. Clinical, audiologic, and conventional histologic tests have failed to shed any light on this problem. Modern immunohistochemical methods may stand a better chance. The Ki-67 monoclonal antibody stains proliferating cells and is used in this study to investigate the growth fraction of 13 skull base schwannomas. The acoustic tumors can be divided into two different growth groups, one with a rate five times the other. The literature is reviewed to see if this differentiation is borne out by the radiologic studies. Distinct growth rates have been reported: one very slow, taking 50 years to reach 1 cm in diameter, a second rate with a diameter increase of 0.2 cm/year, and a third rate five times the second, with a 1.0 cm increase in diameter per year. A fourth group growing at 2.5 cm/year is postulated, but these tumors cannot be followed for long radiologically, since symptoms demand surgical intervention. The clinical implications of these separate growth rates are discussed.     

Hormonotherapy of meningiomas with medroxyprogesterone acetate. Immunohistochemical demonstration of the effect of medroxyprogesterone acetate on growth fractions of meningioma cells using the monoclonal antibody Ki-67

The effect of medroxyprogesterone acetate (MPA) on growth fractions of ex vivo meningiomas is demonstrated in using the Ki-67 monoclonal antibody in three cases of meningiomas operated on in two stages and in meningioma specimens from a group of eight patients operated on in one single stage after MPA therapy. Growth fractions in samples from five meningioma patients not treated with MPA were determined for comparison. In the three cases of two-stage operation of the tumors, the percentage of Ki-67-positive cells in meningioma tissue was lower by a factor of 6, 5, and 3, respectively, after MPA therapy. In meningioma specimens from patients receiving no MPA therapy, Ki-67-positive cells were present in 1.02 +/- 0.48%; in samples from MPA-treated tumors the percentage of Ki-67-positive cells was 0.41 +/- 0.40 (different at p less than 0.02 [Wilcoxon's test]). In comparison to our previously published data on untreated meningiomas analyzed for progesterone receptors (PR), MPA significantly reduced the PR activity. There was no obvious correlation between PR activity and potential suppression of the tumor growth fraction. It is concluded that MPA is attractive because it reduces the growth fractions of most meningiomas and might be suitable for adjuvant hormonotherapy.     

Pathological and clinical associations of Ki-67 defined growth fractions in human prostatic carcinoma.

Estimation of the growth fraction of 153 prostatic carcinoma specimens employing Ki-67 immunostaining was undertaken and its relationship to various clinical parameters investigated. In prostate specimens, the percentage of tumour nuclei expressing Ki-67 antigen was measured and assigned a Ki-67 score. It was observed that high Ki-67 scores were associated with the poorly differentiated tumours, the correlation of this proliferation marker with histological grade was found to be significant (P less than 0.001). No relationship was observed between the Ki-67 score of the primary tumour with either the patient's age or with the primary tumor stage (T category). The metastatic status of the patient at diagnosis and the Ki-67 score of the tumour were correlated (P less than 0.05), higher Ki-67 scores being associated with M1 disease. Life-table analysis of 86 patients who subsequently received androgen withdrawal therapy, was undertaken with reference to the various Ki-67 scores of their primary tumors. A statistically significant difference in survival times was observed in patients whose Ki-67 values were less than 1% (P less than 0.0001) when compared to those patients whose tumours expressed 1% and over Ki-67 positivity, the former having longer survival times. When patients were subdivided according to their metastatic status and similar life-table analyses were carried out, no statistical difference was found between survival times and Ki-67 scores in M0 staged patients. In the M1 population of patients, however, those patients whose tumours were negative for Ki-67 expression had significantly longer survival times than those patients whose tumours exhibited positive Ki-67 staining (P less than 0.01). Comparing M1 staged patients whose prostate tumor cells exhibited less than 1% Ki-67 positive nuclei with M1 staged patients whose prostate tumour cells contained 1% and higher Ki-67 stained nuclei, a significantly longer survival time was found in the former group of patients (P approximately 0.0001).     

Growth fractions of transitional cell carcinomas of the bladder defined by the monoclonal antibody Ki-67

We used an immunohistochemical technique with the monoclonal antibody Ki-67, which recognizes nuclear antigen expressed in proliferating cells to determine the growth fractions of 5 normal mucosa specimens and 55 transitional cell carcinomas of the bladder. Normal mucosa had a mean value of 0.37 +/- 0.35% cells positive for Ki-67, whereas 9 histological grade 1 tumors showed 2.2 +/- 1.5%, 31 grade 2 tumors averaged 10.1 +/- 7.5% and 15 grade 3 tumors yielded 19.5 +/- 9.0%. These values were significantly different from each other (p less than 0.01), with Ki-67 indexes for grade 2 varying from 0.3 to 24.6%. Nonpapillary tumors had significantly higher indexes than papillary tumors (20.1 +/- 8.0 versus 6.7 +/- 5.9, p less than 0.01). The Ki-67 indexes were 4.6 +/- 4.5% for stage Ta (20 cases), 7.8 +/- 4.7% for stage T1 (14) and 20.2 +/- 7.8% for stages equal to or higher than T2 (21). Significant differences were noted between stages Ta and T1 (p less than 0.05) and between stages T1 and T2 or greater (p less than 0.01). Tumors with muscle layer invasion often showed more than 15% Ki-67 positive cells. Our results imply that Ki-67 indexes not only provide objective information to determine a malignant potential but also help to select the treatment.     

Study of aspirated adipose tissue

The author studied the components of aspirated adipose tissue. The several phases of this material were dissociated through decantation and centrifugation. The components were studied “in vitro” by fresh observation with loupes and microscopes. Histologic preparations were also used in this study. The results disclosed a heterogeneous material composed of free fat, blood components, fragments of adipose tissue of different shapes and sizes, collagen septa, vessels and nerves, clots, ruptured cells, and macromolecules of proteases, hemoglobin, and inflammatory proteins. These findings were present in the fat aspirated both with liposuction devices and with syringes.     

The monoclonal antibody Ki-67 as a marker for proliferating cells in stereotactic biopsies of brain tumours

Summary The monoclonal antibody Ki-67 has been tested as a marker of proliferating cells in 52 stereotactic brain tumour biopsies. The antibody reacts with a nuclear protein expressed in G₁,S, G₂n and Mphases of the cell cycle. Using the immunoperoxidase technique on squash preparations the percentage of Ki-67 positive cells was determined as a fraction of the total number of tumour cells present. This Ki-67 index was in close correlation with the histological grade. Highest values were found in a pineal germinoma (46.3%) and in 3 primary cerebral non-Hodgkin lymphomas (mean 39.5%). Among the gliomas, the highest fraction of proliferating cells was seen in 2 anaplastic paediatric brain stem gliomas (mean 17.4%) and in an anaplastic ependymoma (12.5%). Anaplastic astrocytomas and glioblastomas varied considerably with mean values of 9.5% and 8%, respectively. To some extent this variability may reflect tumour heterogeneity which is more likely to manifest in small stereotactic samples than in large tissue specimens obtained during open surgery. Pilocytic astrocytomas, mixed gliomas and fibrillary astrocytomas had moderate to low percentages.Ki-67 staining of squash preparations can easily be performed on a rountine basis and is, in our experience, superior to frozen sections. This method allows the determination of the growth fraction of an individual tumour and could become an important additional criterion for the decision among alternative and potentially harmful therapeutic regimens.     

Growth fractions of human renal cell carcinoma defined by monoclonal antibody Ki-67. Predictive values for prognosis

BACKGROUND: We used immunohistochemical techniques to elucidate the role of growth fractions of renal cell carcinoma in the clinicopathology of the condition and patient survival. METHODS: Fifty-two fresh-frozen nephrectomy specimens were immunostained with Ki-67 monoclonal antibody. Ki-67 indexes were determined to examine the relationship between tumor size, grade, stage and survival curve. This study included 43 men and nine women with the mean age 58.4 +/- 11.7 years, who had been followed up for 39 +/- 25 months. RESULTS: The Ki-67 index ranged from 0.6 to 14.1%, averaging 4.6 +/- 5.8%. It was 2.8 +/- 2.4% in tumors <5 cm, 4.7 +/- 3.6% in tumors > or =5 cm and 7.1 +/- 9.0% in tumors > or =10 cm. The Ki-67 index of grades 1, 2 and 3 tumors was 2.3 +/- 1.1%, 3.3 +/- 2.7% and 12.0 +/- 10.4%, respectively. Grade 3 tumors had a significantly higher Ki-67 index than grade 1 or grade 2 tumors. There was no correlation between the Ki-67 index and tumor stage. Patients with a Ki-67 index < 5.6% had a better prognosis than those with an index > 5.6% (P=0.029). However, multivariate analysis demonstrated that tumor size (P=0.034) and grade (P=0.038) were higher in hazard ratio than the Ki-67 index. CONCLUSIONS: Most renal cell carcinomas had low growth fractions. Although a high Ki-67 index should indicate a poor prognosis, Ki-67 did not correlate to metastasis. We believe it is necessary to investigate the factors, other than growth potential, that affect metastasis.     

The use of the monoclonal antibody Ki-67 in the identification of proliferating cells: application to surgical neuropathology

In order to test its potential application to surgical neuropathology, the monoclonal antibody Ki-67 was used to demonstrate immunohistochemically the proliferating cells in 40 neoplasms of the nervous system. The antibody, which reacts with a nuclear protein expressed in the G1, G2, S, and M phases of the cell cycle, was demonstrated in frozen sections of all lesions. The highest incidence of stained nuclei was found in a metastatic carcinoma (57%). The percentage of stained cells in gliomas was in general agreement with the histologic grade and known biologic behavior of the lesions, ranging from 0.6% in a pilocytic astrocytoma to 12.4% in a glioblastoma multiforme. In the fibrillary astrocytic neoplasms of low cellularity, there were good correlations between the percentages of stained cells and the degrees of nuclear pleomorphism and chromatin density. In meningiomas, schwannomas, and a cerebellar hemangioblastoma, the fractions of labeled nuclei were less than 1%. The percentage of stained cells in pituitary adenomas showed considerable variation among the four cases (0.2-1.5%), the biologic significance of which is unknown. In four of the above cases, Ki-67 staining was performed on air-dried squash preparations with excellent visualization of immunoreactive nuclei. In one case, a hemangioblastoma, no stained nuclei were seen. The results confirm that Ki-67 staining is technically suitable as a diagnostic method, with good correlations between frozen sections and smear preparations. Determination of the replicating cell fraction could become an important additional criterion to predict the biologic behavior of nervous system neoplasms.     

In situ demonstration of renal tubular regeneration using the monoclonal antibody Ki67

The murine monoclonal antibody Ki67 recognizes a nuclear antigen present in all phases of the cell cycle except Go and can be used with a simple indirect immunohistochemical technique to demonstrate cell proliferation in tissue sections. This antibody was applied to 37 unselected renal biopsies showing a wide variety of histological appearances. Ki67-positive nuclei were seen most frequently in tubular epithelium in acute tubulo-interstitial pathology, particularly in renal allograft rejection. Tubular epithelial staining ranged from 0 to 10% of cells. In chronic nephropathies few tubular cells were stained. Staining was seen in glomerular crescents, but was rare in glomerular tufts except those that showed mesangial proliferation where occasional cells stained. This study demonstrates that information regarding cellular proliferation in renal biopsies can be easily obtained using Ki67 immunostaining. This is likely to be a useful investigative tool and may provide clinically useful information.