Cell kinetics of human meningiomas and neurinomas--Ki-67 PAP stain

Seventeen surgically resected meningiomas and six neurinomas including one neurofibroma were labelled with frozen sections using a monoclonal antibody Ki-67, which reacts with a nuclear antigen expressed by proliferating cells. In thirteen classic non-malignant meningiomas, the percentage of stained cells ranged from 0.2 to 3.2% (mean, 1.4%). Those of three recurrencies consisted of anaplastic one and another one with anaplastic component, and one hemangiopericytic type ranged from 2.9 to 8.7% (mean, 4.8%). Four classic non-malignant neurinomas and one neurofibroma had the range from 0.3 to 2.7% (mean, 1.3%). However, one anaplastic neurinoma showed the largest fraction (13.0%) of positive nuclei in all these tumors. These results show, in conclusion, that the determination of Ki-67 immunoreactivity in the cell nuclei of meningiomas and neurinomas can contribute to more objectiveness in histological grading and the higher positive rate could be one of various factors relating to recurrence.     

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.     

Relationship of proliferating cell nuclear antigen (PCNA) in prostatic carcinomas to various clinical parameters.

Proliferating cell nuclear antigen (PCNA) expression was determined immunohistochemically, using a monoclonal antibody PC10, in 102 prostatic carcinoma samples and in prostate tissue from 21 patients with benign prostatic hyperplasis (BPH). The percentage of cells with stained nuclei ranged from 1% to 58% in the carcinoma specimens and 0% to 10% in the BPH specimens. A semiquantitative scoring system was devised for the degree of PCNA positivity observed in the tumors. Statistical analysis of the PCNA score in relation to the histological grade of the tumors gave a significant positive or negative correlation between these parameters P less than 0.001. No significant correlation between PCNA score was, however, seen with metastatic status, T category (TMN classification) of the primary tumor, or the patient's age at diagnosis. In 65 prostatic cancer patients of known survival, those individuals whose tumors had a PCNA score of +/- (less than 10% of nuclei stained) were compared with those patients whose tumors were either 1+, 2+, or 3+ (greater than 10% of nuclei stained). Life table analysis of the two groups indicated that the patients with the lower PCNA score survived significantly longer than those with the higher PCNA scores, P less than 0.04. Comparison of the Ki-67 expression in frozen sections with the PCNA expression in wax-embedded tissue of 86 prostatic carcinomas was also undertaken. A significant correlation between these two parameters was found, P less than 0.001, although the growth fraction estimated by Ki-67 expression was generally lower than that given by the PCNA scoring system.     

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.     

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.     

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).     

Correlation between nucleolar organizer region staining and Ki-67 immunostaining in human gliomas.

Fourteen cases of various grades of gliomas were investigated by an immunohistochemical method using a monoclonal antibody, Ki-67, which reacted with a nuclear antigen in proliferating cells, and the correlation between Ki-67 labeling index and the number of nucleolar organizer regions stained by an argyrophilic method. Four normal brain tissue samples without neoplastic cells, which were obtained at surgery, were also examined for nucleolar organizer region staining. Both the mean number of nucleolar organizer regions and the percentage of Ki-67 positive cells well reflected the histological grade of gliomas (astrocytoma grade 2: Ki-67, 0.5% and nucleolar organizer regions, 1.6; astrocytoma grade 3: Ki-67, 3% and nucleolar organizer regions, 2.5; astrocytoma grade 4: Ki-67, 5.2% and nucleolar organizer regions, 2.8). Also, the percentage of Ki-67 positive cells and the mean number of nucleolar organizer regions were found to be linearly related (r = 0.91). Both values of high-grade astrocytomas were significantly greater than those of low-grade astrocytomas (p less than 0.01 and p less than 0.001). Thus, the mean number of nucleolar organizer regions as well as Ki-67 labeling index reflect the proliferating potential of gliomas.     

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.     

Rates of cycling cells in cryopreserved valvular homograft: a preliminary study

Some investigators claim that the viability of cryopreserved human valvular homograft is necessary for the duration of implanted homograft. In this preliminary study, the percentage of cycling cells in cryopreserved valvular homografts was evaluated with the use of monoclonal Ki-67 antibody. Three human aortic valves were harvested from multiorgan donors and cryopreserved. Sections of 5 microm in thickness were stained with monoclonal Ki-67 antibody. The proportion of endothelial cells with Ki-67 positive nuclei was 1.80 +/- 0.20%. No differences in distribution were observed from basal to marginal sites. Few fibroblasts showed Ki-67-immunopositivity (0.10 +/- 0.06%) while the Ki-67 immunostaining was 0.80 +/- 0.20% in myocytes. Our preliminary study shows that cryopreserved valvular homograft cells are not only viable but they also have the potential to replicate. These data can lead to the hypothesis that valvular cells could actively replicate even after implantation, permitting cellular renewal and regeneration of extracellular matrix's components.     

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.     

Study of growth fraction on fine needle aspirated prostatic tissue smear using monoclonal antibody Ki-67

Immunohistochemical staining using monoclonal antibody Ki-67 was performed in 30 patients with benign prostatic hypertrophy (BPH), one with prostatic tuberculosis (TB), 22 with prostatic adenocarcinoma, one with prostatic transitional cell carcinoma and one with prostatic invasion from a bladder cancer. Specimens were aspirated from the prostate transrectally and a cytological smear were made. This antibody is specific for a proliferation-associated nuclear antigen. Alkaline phosphatase anti-alkaline phosphatase stained immunopositive nuclei red making positive or negative specimens easy to recognize. In BPH and TB smears, no immunopositive cell was reactive with Ki-67. In prostatic malignancy were found many immunopositive cells ranging from 2.5 to 10.2% (mean 5.9%) in prostatic adenocarcinoma (n = 22), and from 11.9 to 24.3% (mean 18.1%) in prostatic transitional cell carcinoma. Transitional cell carcinoma may have a much greater growth fraction than adenocarcinoma in prostatic tissue. Poorly differentiated adenocarcinoma showed a higher growth fraction (from 4.2 to 10.2%, mean 6.9%) than well differentiated (from 3.1 to 8.9%, mean 5.8%) and moderately differentiated adenocarcinoma (from 2.5 to 10.1%, mean 5.6%), but this difference was not significant. There was no correlation with age, clinical stage, bone metastasis or B?cking's cytological grade. In conclusion, immunohistochemical staining using Ki-67 on aspirated prostatic smear is visualizes the growth fraction of prostatic disease well and is useful to diagnose 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.     

Urothelial carcinoma with an inverted growth pattern can be distinguished from inverted papilloma by fluorescence in situ hybridization, immunohistochemistry, and morphologic analysis

Inverted papilloma of the urinary bladder and urothelial carcinoma with an inverted (endophytic) growth pattern may be difficult to distinguish histologically, especially in small biopsies. The distinction is important as these lesions have very different biologic behaviors and are treated differently. We examined histologic features and undertook immunohistochemical staining and UroVysion fluorescence in situ hybridization (FISH) to determine whether these methods could aid in making this distinction. We examined histologic sections from 15 inverted papillomas and 29 urothelial carcinomas with an inverted growth pattern. Each tumor was stained with antibodies to Ki-67, p53, and cytokeratin 20. In addition, each tumor was examined with UroVysion FISH for gains of chromosomes 3, 7, and 17 and for loss of chromosome 9p21 signals. None of the inverted papillomas stained positively for Ki-67 or for cytokeratin 20. Only 1 of 15 inverted papillomas stained positively for p53. By contrast, 66%, 59%, and 59% of urothelial carcinomas with an inverted growth pattern stained positively for Ki-67, p53, and cytokeratin 20, respectively. Only 3 of the urothelial carcinomas stained negatively for all 3 immunohistochemical markers. UroVysion FISH produced normal results for all cases of inverted papilloma. By contrast, 21 of 29 cases (72%) of urothelial carcinoma with an inverted growth pattern demonstrated chromosomal abnormalities typical of urothelial cancer and were considered positive by UroVysion FISH criteria. Morphologic features, as well as immunohistochemical stains (including stains for Ki-67, p53, and cytokeratin 20) and/or UroVysion FISH can help to distinguish inverted papilloma from urothelial carcinoma with an inverted growth pattern.     

Immunocytochemical staining of estrogen receptor in conventional formalin-fixed paraffin sections in human breast cancer

Immunocytochemical staining for estrogen receptor (ER) was examined in conventional formalin-fixed paraffin sections in 63 patients with breast cancer. The ER staining was performed by avidin-biotin peroxidase complex method (ABC) using monoclonal antibody against ER (H222). The ER stainability in formalin-fixed paraffin sections was compared with the levels of ER measuring dextran-coated charcoal (DCC) method, and with the stainability of ER in frozen sections. ER positive rates of paraffin sections and frozen sections were 52%, and 65% respectively. ER positive level of DCC method was seen in 62 percent of the cases. Results of ER staining in paraffin sections correlated well to those of DCC method and to those of ER staining in frozen sections. In paraffin sections as well as in frozen sections, ER staining was located at the nuclei of cancer cells. Furthermore, the variety that this method for ER can be used for retrospective studies of ER on stored blocks of breast cancer.     

Immunohistochemical determination of the estrogen receptor content of gastrointestinal adenocarcinomas.

Recently there have been several reports documenting the presence of estrogen receptors (ERs) in human gastrointestinal (GI) malignancies, raising the possibility that these cancers may be hormonally manipulated. To test this hypothesis, 68 frozen GI tissue specimens were examined for the presence of ERs within the cell nuclei by immunohistochemical staining. There were 51 cancers (25 gastric, 26 colon) and 17 normal tissue specimens (six gastric, 11 colon). Tissue sections 4 to 6 microns thick were incubated with monoclonal antibody H222SP psi, then stained by the peroxidase-antiperoxidase technique for visualization of the ER. The staining was semiquantitatively graded from 0 to 3+ depending on both the intensity of staining and the percentage of cell nuclei stained. A breast cancer specimen known to be strongly positive for the ER was used as a positive control. The 30 male and 21 female cancer patients had a median age of 59 years. All tumors were adenocarcinomas. Eight per cent of the gastric cancers were poorly differentiated, while 94 per cent of the colon cancers were moderately well to well differentiated. Using weak staining of at least 20 per cent of the cell nuclei as the minimum requirement for an ER positive tumor (1+, 0/51 tumors and 0/17) normal specimens were positive for ER. Only three out of 25 (12%) gastric tumors, and two out of 26 (8%) colon tumors demonstrated any staining; each exhibited weak staining of only five to ten per cent of the tumor nuclei.(ABSTRACT TRUNCATED AT 250 WORDS)     

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.     

Growth rate of human pituitary adenomas

The immunohistological detection of a proliferation-associated nuclear antigen by the monoclonal antibody Ki-67 allows the determination of the growth fraction in human cell populations. In this study, biopsy specimens of 31 pituitary adenomas representing all major endocrine types were examined. All adenomas contained proliferating cells and the percentage of nuclei that were immunoreactive to Ki-67 ranged from 0.1% to 3.7%. Low values (0.1% to 1.0%) were present in 11 endocrine-inactive adenomas and higher values (1.1% to 1.5%) were found in six acromegalic patients. The percentages of Ki-67-positive cells in 12 prolactinomas and two adenomas from patients with Cushing's disease covered the entire range (0.1% to 3.7%). Preoperative bromocriptine treatment of prolactinomas did not influence Ki-67 expression. Invasive adenomas, as determined by preoperative computerized tomography, surgical observation, and histological examination of the sella dura demonstrated significantly higher Ki-67 values (average 1.15%) than noninvasive adenomas (average 0.60%). Determination of the incidence of proliferating cells by Ki-67 immunoreactivity represents a new tool for intraoperative quantitative assessment of tumor growth characteristics and may aid in the planning of adjuvant therapy and estimation of prognosis.     

Immunohistochemical Analysis of Radical Prostatectomy Specimens After 8 Months of Neoadjuvant Hormonal Therapy

Neoadjuvant hormone therapy (NHT) prior to radical prostatectomy (RP) results in residual foci of atrophic glands, which can be difficult to identify with hematoxylin-eosin staining, raising the possibility that the low positive-margin rates are an artifact of pathologic understaging. The purpose of this study was to evaluate changes in prostate specific antigen (PSA) and prostatic acid phosphatase (PAP), as well as proliferation marker Ki-67 and Bcl-2 oncoprotein, by immunostaining after 8 months of NHT. Twenty-nine men with clinically confined prostate cancer who received 8 months of NHT and had both pretreatment biopsy and RP specimens obtained at Vancouver Hospital constituted the treatment group. The control group consisted of 23 RP specimens from patients not receiving NHT. Sections were stained with antibodies against PSA, PAP, proliferation marker Ki-67, and the antiapoptosis protein Bcl-2. The PSA and PAP immunostaining were graded for percentage of positive tumor cells and intensity of staining, while Ki-67 and Bcl-2 staining was graded according to the percentage of positive tumor cells. Absent or low percentage-positive PSA and PAP staining was observed in 40% to 50% of the NHT-treated RP specimens but none of the needle biopsy or untreated control RP specimens. Low-intensity PSA and PAP staining was detected only in RP specimens after NHT treatment, and then in only 20% of cases. Low or absent Ki-67 staining was noted in 78% of the NHT- treated RP specimens, compared with only 13% of the matched pre-NHT needle biopsies and 26% of untreated RP specimens. The percentage of specimens with high (>5%) Ki-67 staining decreased from 37% in the pre-NHT needle biopsies to 8% in the NHT-treated RP specimens. Bcl-2 staining increased after treatment with NHT, with 20% of the needle biopsies having high (>5%) Bcl-2 staining compared with 53% of the NHT-treated RP specimens. The frequency of low Bcl-2 staining (<1%) decreased from 53% in the pre-NHT needle biopsies to 27% in the NHT-treated RP specimens. Although PAP and PSA staining decreased after NHT, both markers remain sufficiently positive to be used as epithelial markers to help detect residual foci of prostate cancer that are difficult to identify on H&E-stained slides after NHT. Increased Bcl-2 after NHT, even in early-stage disease, is consistent with its role in the prevention of apoptosis and progression to androgen independence. Low levels of Ki-67 staining indicates a low probability of proliferation and outgrowth of androgen-independent clones after 8 months of NHT.     

Comparison of the basal cell-specific markers, 34betaE12 and p63, in the diagnosis of prostate cancer

The basal cell-specific cytokeratin antibody (34betaE12) is widely used to aid in the diagnosis of cancer in challenging prostate needle biopsies (NBX) and transurethral resections of the prostate (TURP). Because prostate carcinoma (PCa) lacks basal cells, the absence of basal cell as determined by 34betaE12 can aid in the confirmation of a histologically suspicious lesion. However, false-negative staining occurs because of patchy cytoplasmic staining, making a definitive diagnosis difficult. A recently identified basal cell marker p63, a p53 homologue, stains basal cell nuclei but not secretory cells. The aim of this study is to determine if the p63 antibody offers any clinically useful advantage over 34betaE12 in the diagnosis of challenging atypical prostate lesions. Ninety-four cases, comprised of 25 consecutive prostate NBX and 2 TURP with an atypical suspicious focus, 55 NBX cases of histologically unequivocal PCa and 12 TURP specimen removed for benign prostate hyperplasia, were stained with the monoclonal antibodies 34betaE12 and 4A4 anti-p63. Basal cell staining intensity, percentage basal cell-positive glands in benign, malignant, and atypical foci, and number of benign glands not staining were evaluated for 34betaE12 and p63 stains. A total of 67 prostate NBX cases, including one TURP, were diagnosed with PCa, 1 atypical small acinar proliferation, 10 benign, and 4 cases excluded because of lost tissue on step sections. None of the 67 PCa NBX cases demonstrated 34betaE12 or p63 immunoreactivity (100% specific). Whereas 57 of 108 (53%) prostate NBX cores from 78 cases demonstrated a similar percentage of basal cell staining for both antibodies, 45 of 108 (41%) NBX cores demonstrated a higher percentage of p63 basal cell staining in benign glands. Only 6 of 108 NBX (6%) cores had a higher percentage of basal cell staining with 34betaE12 (Wilcoxon signed rank test, p <0.0001). Lack of basal cell staining in more than two benign glands occurred in 25 of 108 (23%) and 10 of 108 (9%) prostate NBX cores stained with 34betaE12 and p63, respectively. In the vast majority of atypical cases, both 34betaE12 and p63 staining differences were not clinically significant, except in 2 of 27 (7%) cases p63 offered diagnostic utility beyond the 34betaE12 immunostain. p63 in these cases demonstrated discontinuous but strong staining in atypical glands and adjacent benign glands, whereas 34betaE12 failed to stain optimally in this critical area. For 12 TURP cases the mean percentage basal cell positivity in benign glands was 75% and 95% for 34betaE12 and p63, respectively (p = 0.006). Lack of basal cell staining in more than two glands occurred in 12 of 12 (100%) and 2 of 12 (17%) TURP specimens stained with 34betaE12 and p63, respectively (p <0.0001). In summary, 34betaE12 and p63 are highly specific for basal cells and therefore are negative in areas of PCa. p63 is more sensitive than 34betaE12 in staining benign basal cells, particularly for TURP specimens, offering slight advantage over 34betaE12 in diagnostically challenging cases. p63 may be used as an alternative to 34betaE12 stain for difficult prostate lesions.     

Growth fractions of breast cancer in relation to epidermal growth factor receptor and estrogen receptor

Growth fractions detected by a monoclonal antibody, Ki-67, were examined in 40 human breast cancer tissues and the results compared with the immunocytochemical reactivities of epidermal growth factor receptor (EGFR) and estrogen receptor (ER). The proportion of proliferating cells displaying Ki-67 positive staining was significantly higher in the EGFR positive tumors than in the EGFR negative tumors (p<0.01). The average percentage of Ki-67 positive cells in the EGFR positive tumors was 19.9 per cent, whereas that in the EGFR negative tumors was 8.0 per cent. By contrast, an inverse relationship between the proportion of proliferating cells and ER positive cells detected by anti-ER monoclonal antibody was observed. This data indicated the difference in growth fractions with relation to the EGFR and ER status of breast cancer.