Proliferating cell nuclear antigen immunohistochemistry using monoclonal antibody 19A2 and a new antigen retrieval technique has prognostic impact in archival paraffin-embedded node-negative breast cancer

We evaluated whether proliferating cell nuclear antigen (PCNA) immunohistochemistry with antigen retrieval could be used as a measure of cell proliferation in archival, formalin-fixed, paraffin-embedded tissues and whether the staining results have long-term prognostic significance in axillary node-negative breast cancer. Primary tumor samples obtained from 109 axillary-node-negative breast cancer cases were used for the study. The best staining results were obtained with the 19A2 antibody after microwave heating in a solution of saturated lead thiocyanate. Using this method, there was a significant correlation (linear regression, r = 0.580, P < 0.001) between the proportion of PCNA19A2-positive carcinoma cells (PCNA19A2 score) and DNA flow cytometric S phase fraction. A high PCNA19A2 score was associated with high mitotic count, DNA aneuploidy, and absence of estrogen receptors. Axillary-node-negative patients with a high PCNA19A2 score (cut-point 8%) had significantly worse prognosis than those with a low PCNA19A2 score (P = 0.008). According to a Cox multivariate analysis, PCNA19A2 score had independent prognostic value but only if S phase fraction was excluded from the analysis. In our study, the PCNAPC10 score correlated weakly only with primary tumor size (analysis of variance) and prognosis (5-year univariate survival analysis), but the significance of these findings needs further evaluation. In conclusion, PCNA immunohistochemistry with the 19A2 antibody after an appropriate antigen retrieval treatment may offer a useful alternative to DNA flow cytometry for the analysis of cell proliferation activity from formalin-fixed, paraffin-embedded breast carcinomas.

Comparative genomic hybridization: a rapid new method for detecting and mapping DNA amplification in tumors

Recent evidence indicates that many more genes than the currently known oncogenes may undergo amplification in tumors. We have developed a new technique, Comparative Genomic Hybridization (CGH), which allows rapid detection of DNA amplification anywhere in the tumor genome and maps the amplified sequences on normal chromosomes. CGH is based on a competitive in situ hybridization of differentially labeled tumor DNA and normal DNA to a normal human metaphase spread. Regions of gain of DNA sequences are seen as an increased color ratio of two fluorochromes used to detect the labeled DNAs. Over 20 different regions of amplification have been identified using CGH.

Cathepsin D expression detected by immunohistochemistry has independent prognostic value in axillary node-negative breast cancer

PURPOSE

Increased expression of the lysosomal protease cathepsin D (CD) has been implicated in the metastatic progression of breast cancer. This study was designed to determine the prognostic significance of CD expression in axillary node-negative (ANN) breast cancer. The relationship of CD expression and onset of soft tissue recurrences and visceral metastatases was also studied.

PATIENTS AND METHODS

We analyzed a population-based group of 262 ANN breast cancer patients, none of whom had received any adjuvant chemotherapy or endocrine therapy. An immunohistochemical method based on a new monoclonal antibody (1C11) with a distinct epitope specificity made it possible to study CD expression from archival paraffin-embedded specimens and to distinguish staining in tumor cells from the high-level expression found in tumor-infiltrating macrophages.

RESULTS

High-level CD expression, as defined by cytoplasmic immunoreactivity in greater than 10% of the cancer cells, was found in 95 cases (36%). High-level CD expression was associated with large primary tumor size (P = .014), but not with histologic grade, estrogen and progesterone receptors, DNA index, or S-phase fraction, or with c-erbB-2 and p53 overexpression. Patients with CD-positive tumors developed significantly more often both soft tissue recurrences and visceral metastases (P = .0007) and had a significantly shorter disease-free survival (P < .0001). Eight-year overall survival of patients with high-level CD expression was 64% as compared with 90% in those with low-level expression (relative risk, 2.97; 95% confidence interval [Cl], 1.6 to 4.4; P < .0001). According to a Cox multivariate model and a regression-tree analysis, high-level CD expression was an independent predictor of poor overall survival in conjunction with tumor size and S-phase fraction.

CONCLUSION

These results indicate that CD expression determined by immunohistochemistry is a powerful prognostic factor in ANN breast cancer. The most significant prognostic information was obtained when CD expression (predicting metastatic activity) was combined with estimate of cell-proliferation rate (S-phase fraction).

Comparative genomic hybridization for molecular cytogenetic analysis of solid tumors

Comparative genomic hybridization produces a map of DNA sequence copy number as a function of chromosomal location throughout the entire genome. Differentially labeled test DNA and normal reference DNA are hybridized simultaneously to normal chromosome spreads. The hybridization is detected with two different fluorochromes. Regions of gain or loss of DNA sequences, such as deletions, duplications, or amplifications, are seen as changes in the ratio of the intensities of the two fluorochromes along the target chromosomes. Analysis of tumor cell lines and primary bladder tumors identified 16 different regions of amplification, many in loci not previously known to be amplified.

Expression of epidermal growth factor receptor and ERBB2 (HER-2/Neu) oncoprotein in prostatic carcinomas

Expression of epidermal growth factor receptor (EGFR) and ERBB2 oncoprotein were studied in paraffin-embedded normal (n = 2), hyperplastic (n = 17), and malignant (n = 147) prostatic tissues by immunohistochemistry. Strong immunoreactivity was detected in the epithelial cells of all normal and hyperplastic prostates with a new EGFR antibody (Mab31G7). In prostatic carcinomas, the EGFR immunoreactivity was variable with 47% showing uniform, 39% partial, and 14% no staining. Tumors with partial or uniform EGFR immunoreactivity were locally more advanced and of higher histological grade than the EGFR-negative tumors. EGFR-positive tumors also had two to three times higher S-phase fraction, suggesting that EGFR expression conferred proliferative advantage. Patients who had either partially or uniformly EGFR-positive carcinomas had a worse 10-yr progression-free (p = 0.05), overall (p = 0.03), and prostatic carcinoma-specific (p = 0.007) survival than those with EGFR-negative carcinomas. However, according to a multivariate analysis, EGFR did not have independent prognostic value. None of the normal, hyperplastic, or malignant prostate tissues showed clearly positive ERBB2 immunoreactivity with MAb1 antibody.

Association of overexpression of tumor suppressor protein p53 with rapid cell proliferation and poor prognosis in node-negative breast cancer patients

BACKGROUND

Recent evidence indicates that a subset of axillary node-negative (ANN) breast cancer patients can benefit from adjuvant therapy. Reliable prognostic markers are needed, however, to help clinicians identify these patients and arrive at more rational treatment decisions.

PURPOSE

Mutations of the p53 tumor suppressor gene often result in overexpression of the p53 protein. In this study, we evaluated the prognostic significance of p53 protein overexpression in patients with ANN breast cancer. We also studied the association between the tumor cell proliferation rate and overexpression of the p53 and c-erbB-2 proteins, both of which have been implicated in cell cycle control. The c-erbB-2 protein is the product of the ERBB2 gene.

METHODS

Two hundred eighty-nine ANN cases were randomly selected from a population-based cohort of patients who had not received any kind of adjuvant chemotherapy or endocrine therapy. Overexpression of the p53 and c-erbB-2 proteins was studied immunohistochemically in archival paraffin-embedded tumor samples, using the CM-1 polyclonal and the TAb 250 monoclonal antibodies, respectively. The tumor cell proliferation rate was measured as the S-phase fraction by DNA flow cytometry. Statistical analyses were performed using BMDP software.

RESULTS

High-level p53 protein overexpression, found in 41 of the 289 tumors, was most common in tumors with high histologic grade, negative estrogen receptor status, c-erbB-2 protein overexpression, DNA index greater than 1.3, or high S-phase fraction. The lowest S-phase levels were found in tumors with neither p53 nor c-erbB-2 protein overexpression; the highest levels were seen in tumors showing overexpression of both proteins (P less than .0001). Both p53 and c-erbB-2 overexpression, as well as tumor size, had independent prognostic value in multivariate analysis. Eight-year survival of patients with p53 protein overexpression was 56% compared with 81% in patients with no overexpression (relative risk, 3.7; P less than .0001). If the S-phase fraction was included in a Cox regression analysis, however, only the tumor size and the S-phase fraction emerged as independent predictors of survival.

CONCLUSIONS

Overexpression of the p53 and c-erbB-2 proteins indicates a high malignant potential in ANN breast cancer, but it is not a significant prognostic factor independent of the cell proliferation rate. The correlation between overexpression of these proteins and an increased S-phase fraction suggests that they may confer a proliferative advantage to cancer cells in vivo.

ERBB2 amplification in breast cancer analyzed by fluorescence in situ hybridization

We illustrate the use of fluorescence in situ hybridization (FISH) for analysis of ERBB2 oncogene copy number, the level of amplification (here defined as the ratio of ERBB2 copy number to copy number of chromosome 17 centromeres), and the distribution of amplified genes in breast cancer cell lines and uncultured primary breast carcinomas. The relative ERBB2 copy number determined by FISH in 10 breast cancer cell lines correlated strongly with Southern blot results (r = 0.98) when probes for an identical reference locus were used in the two methods. Metaphase analysis of cell lines showed that amplified ERBB2 copies always occurred in intrachromosomal clusters but that the number and chromosomal location of these clusters varied among the cell lines. In interphase nuclei of primary tumors showing ERBB2 amplification (10/44), ERBB2 copies were seen as one to four clusters, also suggesting intrachromosomal localization. Regardless of the average level of amplification, all these tumors contained highly amplified cell subpopulations with at least 25, and sometimes more than 100, ERBB2 copies per cell. Tumors that did not show amplification by FISH (34/44) had an average of one to five ERBB2 copies scattered randomly in the nuclei and completely lacked cells with high copy levels. FISH results on primary tumors were concordant with slot blot results on amplification and with immunohistochemical detection of overexpression. Quantitative analysis of ERBB2 amplification by FISH may improve prognostic assessments based on the pattern of amplification and detection of heavily amplified tumor cell subpopulations.

Small subgroup of aggressive, highly proliferative prostatic carcinomas defined by p53 accumulation

BACKGROUND

Mutations in the p53 gene resulting in the accumulation of altered p53 proteins with prolonged half-life have been found in a large variety of human malignancies.

PURPOSE

We studied the significance of p53 protein accumulation in prostatic carcinoma.

METHODS

The material consisted of 137 paraffin-embedded, primary prostatic carcinomas. Accumulation of p53 protein was studied by immunohistochemical staining using a polyclonal p53-specific CM-1 antibody. Proliferation activity was determined by DNA flow cytometry and by immunohistochemical detection of proliferative cell nuclear antigen (PCNA) using a monoclonal PC10 antibody.

RESULTS

Eight (6%) of the tumors showed intense p53 staining in more than 20% of the tumor cells, 15 (11%) had only lower level immunoreactivity, and 114 (83%) showed no staining. High-level p53 accumulation was associated with high histologic grade (P less than .001), DNA aneuploidy (P less than .05), and high cell proliferation rate as defined by flow cytometric S-phase analysis (P less than .01) or PCNA expression (P less than .01). High-level p53 accumulation predicted short, progression-free interval (P less than .01) and poor survival (P less than .001), with about a 12-fold relative risk of death as compared with p53-negative cases. Low-level p53 accumulation had no prognostic significance.

CONCLUSIONS

Accumulation of p53 confers proliferative advantage for prostatic carcinoma cells and defines a small subgroup of highly malignant carcinomas.

Significance of variation in DNA flow cytometric analyses from paraffin-embedded breast cancers. Evaluation of the grading efficiency of ploidy determination, DNA index, and S-phase fraction

116 paraffin-embedded breast cancer samples were analyzed by flow cytometry. From each sample 3 consecutive 50 microns sections were cut for the study. The presence of neoplastic tissue was verified from light microscope sections cut before and after the adjacent sections. One laboratory started with one section from each block and was allowed extra sections when needed for analysis. At the end the laboratory obtained results from all 116 cases. The rest of the samples were studied by 2 other laboratories. Samples with results from 2 or 3 laboratories then allowed variability analysis and the estimation of the grading efficiency in a 2-grade system. Inconsistency in diploidy/aneuploidy distinction was present in 36 of 111 (32.4%) cases studied by two or three laboratories. This inconsistency was less obvious in samples graded as multiploid by at least one of the laboratories. The grading efficiency as analyzed from the results of 3 laboratories was 0.89, and of 2 laboratories, 0.84. The DNA index showed a slightly higher grading efficiency. At the cutoff point of 1.3, 91% of cases could be expected to be correctly classified into low ploidy and high ploidy groups (grading efficiency 0.91). The S-phase fraction had a mean grading efficiency of 0.89, a performance comparable to that of diploidy/aneuploidy distinction. In the light of the available data the flow cytometric analysis can add to the consistency of grading, especially when compared with subjective histological grading. However, the data do not suggest that flow cytometric analysis of paraffin sections as a grading method would be more consistent than quantitative histopathology from sections.

Detection of retinoblastoma gene copy number in metaphase chromosomes and interphase nuclei by fluorescence in situ hybridization

Fluorescence in situ hybridization (FISH) was applied to detect the copy number of the retinoblastoma (RB1) tumor suppressor gene in metaphase chromosomes and interphase nuclei. We used 14 lambda phage clones spanning the whole RB1 gene region as a probe and obtained a specific hybridization signal in normal metaphase chromosomes at 13q14. Normal interphase nuclei showed two RB1 signals in about 90% of cases, whereas two cell lines with cytogenetically defined deletions involving the RB1 gene showed only one hybridization signal in about 80% of the nuclei. Analogous changes were detected in metaphase chromosomes. Multicolor FISH with subsets of the phage clones allowed visualization of subregions within the 200-kb gene in interphase nuclei. Analysis of clinical breast cancer samples showed that most of the cells contained two copies of the RB1 gene, even when restriction fragment length polymorphism analysis showed loss of heterozygosity (LOH) at the RB1 locus. This indicates that LOH at the RB1 locus in breast cancer cells probably involves mechanisms other than physical deletion.

Association of c-erbB-2 protein over-expression with high rate of cell proliferation, increased risk of visceral metastasis and poor long-term survival in breast cancer

c-erbB-2 protein over-expression was studied immunohistochemically in 319 paraffin-embedded breast carcinomas representing 89% of all breast-cancer cases operated in the Tampere University Hospital between 1977 and 1981. The immunohistochemical evaluation of c-erbB-2 was optimized using protease pre-treatment and verified using antibodies for both the external and the internal domains of the protein. c-erbB-2 over-expression was found in 72 (23%) of the 319 cases and was associated with high histological and nuclear grade (p less than 0.0001), DNA aneuploidy (p = 0.003), high tumor S-phase fraction (p less than 0.0001), and lack of estrogen (p less than 0.0001) and progesterone (p = 0.03) receptors. Overall, breast-cancer patients with c-erbB-2 over-expression had about 2.2-fold relative risk (RR) of death (p less than 0.001) as compared with those without over-expression. According to a multivariate analysis, c-erbB-2 over-expression was an independent prognostic factor in the whole material as well as in the node-negative sub-set. In node-negative breast-cancer tumor size, S-phase and c-erbB-2 status defined a large patient group with only 4% 5-year and 15% 10-year mortality rate without adjuvant therapy. In comparison with c-erbB-2-negative tumors, those with over-expression of this gene metastasized 3 times more often (p = 0.0002) to the lungs, liver and brain and 3 times less often to the bone. Our findings suggest that the prognostic value of c-erbB-2 over-expression may be related not only to increased cell proliferation rate but also to a distinctive pattern of metastasis.

Prognostic value of analysis of DNA in pancreatic adenocarcinoma by flow cytometry

DNA was analysed by flow cytometry in paraffin-embedded tumour specimens from 58 patients who had undergone resection of pancreatic ductal adenocarcinoma, to see if there was any correlation between DNA analysis and survival. Because of the poor quality of the DNA histogram five cases were excluded from the analysis of DNA-ploidy and 10 from the analysis of the synthesis phase fraction. Aneuploidy was detected in 11 (21%) of the 53 tumours. Neither aneuploidy nor synthesis phase fraction correlated significantly with size, stage or differentiation of the tumours. The survival of the patients with DNA-aneuploid tumours (median 9 months) did not differ significantly from that of the patients with diploid tumours (median 14 months). Four patients survived for 5 years or longer, two of whom had aneuploid tumours. Synthesis phase fraction did not correlate with survival. Using univariate survival analyses, location of the tumour in the head of the pancreas (p = 0.02), a tumour diameter of less than 3.8 cm (p = 0.003), tumour stages I and II (p = 0.03), and a well differentiated tumour (p = 0.04) correlated with favourable survival. In a Cox's regression analysis, however, only the diameter of the tumour had independent prognostic value. We conclude that DNA analysis by flow cytometry is not helpful in selecting patients with resectable pancreatic carcinoma who will benefit from resection.

Flow cytometric analysis of DNA ploidy and S-phase fraction from prostatic carcinomas: implications for prognosis and response to endocrine therapy

We analysed ploidy and S-phase fraction (SPF) from 78 paraffin-embedded primary prostatic carcinomas by DNA flow cytometry. DNA aneuploidy and above median (4.2%) SPF were both associated with high tumour grade, large size of prostate and presence of distant metastases. Both aneuploidy and high SPF (greater than 4.2%) indicated short 10-year progression-free (P = 0.01 for ploidy and P = 0.0002 for SPF), overall (P = 0.004 and P less than 0.0001) as well as prostate cancer survival (P = 0.002 and P less than 0.0001). Ten-year overall survival rate was 45% in cases with SPF below 4.2% and 0% in those with higher values, whereas the corresponding prostate cancer-specific survival rates were 80% and 11%, respectively. None of the seven tumours with SPF above 12% showed an objective response to endocrine therapy, whereas 26/49 (52%) of those with lower SPF values responded (P = 0.01). DNA ploidy, tumour grade, T-stage or M-stage did not significantly correlate with endocrine responsiveness. SPF was also the best predictor of progression free survival in patients treated hormonally. In conclusion, detection of high SPF in prostate cancer may indicate lack of hormonal responsiveness and poor prognosis.

Cigarette smoking alters sympathoadrenal regulation by decreasing the density of beta 2-adrenoceptors. A study of monitored smoking cessation

We report the effects of monitored smoking cessation on adrenergic regulation in chronic smokers. The beta 2 adrenoceptor density of mononuclear leukocytes (MNLs) and plasma catecholamines was analyzed before cessation and 2, 3, and 8 weeks after cessation. We found a progressive increase in beta-adrenoceptor density after smoking cessation. During smoking the beta-adrenoceptor density was 1.456 +/- 83 (mean +/- SEM) binding sites per cell (n = 10), whereas 3 weeks after cessation the density was 1,774 +/- 157 sites per cell (n = 10; p less than 0.05), and at 8 weeks, 1,900 +/- 227 sites per cell (n = 8; p less than 0.05), representing an overall increase of 23%. Smoking cessation had no effect on binding affinity nor on lymphocyte subgroup distribution. The density of MNL cell beta-adrenoceptors in age-matched nonsmoking men was higher, at 1,896 +/- 271 sites per cell, than that of the chronic smokers before cessation, 1,419 +/- 117 sites per cell (n = 14; p less than 0.01). Plasma epinephrine decreased as a result of cessation from 0.36 pmol/ml (0.26-0.44, 95% confidence interval; baseline) to 0.26 pmol/ml (0.20-0.32) at 8 weeks (p less than 0.05), and norepinephrine decreased from 2.09 pmol/ml (1.38-2.80) to 1.69 pmol/ml (1.14-2.24; p = 0.06). We conclude that stopping smoking progressively increases beta 2-adrenoceptor density on MNL cells. Eight weeks after cessation the adrenoceptor density reaches the corresponding level of nonsmokers. These reversible changes in adrenergic regulation after smoking cessation may be associated with the relatively rapid reduction in cardiovascular disease risk among ex-smokers.

Primary undifferentiated small cell carcinoma of the esophagus: clinicopathological and flow cytometric evaluation of eight cases

We present a clinicopathological and flow cytometric evaluation of eight primary small cell carcinomas of the esophagus representing 1.5% of all esophageal malignancies diagnosed during a 22-year period (1965-1987) in the Tampere University Central Hospital. The mean age of the patients (four male and four female) was 67 years (range 55-75 years). Five cases had distant metastases at the time of diagnosis. Three patients were treated by esophageal resection, one by laser vaporisation, and four by chemotherapy. The median survival time was 4 months (range 9 days to 8 months). A complete local response to chemotherapy in serial esophagogramms was detected in one patient. All four patients given chemotherapy survived longer than those treated with esophageal resection only. Four (67%) of the six carcinomas analyzed by DNA flow cytometry contained DNA-aneuploid stemlines. The median S-phase fraction of these small cell carcinomas was high (16.3%), reflecting rapid cell proliferation rate, which may be related to their responsiveness to chemotherapy.

Improved prognostic impact of S-phase values from paraffin-embedded breast and prostate carcinomas after correcting for nuclear slicing

Nuclear debris may significantly interfere with the analysis of S-phase fraction (SPF) from paraffin-embedded tumors. We used a background subtraction algorithm to compensate for the effects of slicing of tumor cell nuclei during preparation of paraffin-embedded specimens. DNA histograms were analyzed from 88 node-negative breast and from 78 prostatic carcinomas. Median SPFs corrected for nuclear slicing were lower than uncorrected ones in both breast cancer (7.6% vs. 5.7%) and prostate cancer (6.7% vs. 4.2%). The median SPF value in each group was used as a cut-off point in survival studies. As compared with the uncorrected SPFs, corrected SPF levels resulted in a more significant survival difference between breast cancer patients with above and below median SPF (p = 0.0014 vs. p = 0.014) and in a higher relative risk (RR) of death (4.5 vs. 3.1). The same was true for prostate cancer survival (p less than 0.0001 vs. p = 0.002) and RR (5.3 vs. 3.1). Compared with the exponential background subtraction method, the sliced nuclei correction was more reproducible and could be applied in all evaluable histograms without the risk of overcompensation. In conclusion, our results support the use of background correction with the sliced nuclei model in DNA flow cytometric studies of archival tissues.

Steroid receptors and Ki-67 reactivity in ovarian cancer and in normal ovary: correlation with DNA flow cytometry, biochemical receptor assay, and patient survival

Steroid hormone receptors and reactivity for Ki-67 proliferation antigen were studied immunohistochemically in non-neoplastic post-menopausal human ovary and in 29 ovarian cancers. In the normal ovary, oestrogen (OR) and progesterone receptors (PR) were found in the surface epithelium and PR also in the ovarian stroma. Of the ovarian carcinomas 38 per cent (11/29) contained OR and 69 per cent (20/29) PR. Oestrogen receptor expression was confined to malignant cells, whereas PR was present occasionally also in the tumour stroma. In most cases, ORs and PRs were found only in a small population of cancer cells. The growth fractions assessed by the percentage of Ki-67-positive cells ranged from 1 to 59 per cent (mean 19.7 per cent) with a significant correlation (r = 0.74, P less than 0.0001) to S-phase values (mean 12.9 per cent, range 1.2-25.9 per cent) determined by DNA flow cytometry. High Ki-67 (greater than or equal to 15 per cent) and S-phase levels (greater than or equal to 7.5 per cent) correlated with advanced disease stage and patient survival but not with OR or PR status, suggesting that hormone-receptor pathways and proliferative activity are not related in ovarian cancer. Positive OR status, however, identified patients with a better prognosis (P = 0.02), suggesting a correlation with tumour differentiation. The independent prognostic value of oestrogen receptor status and Ki-67 remains to be determined, but the prognostic impact of Ki-67 was comparable to that of S-phase values.

Inter-laboratory comparison of DNA flow cytometric results from paraffin-embedded breast carcinomas

Consecutive sections from 33 paraffin-embedded human breast carcinomas without intratumor heterogeneity were sent for flow cytometric (FCM) DNA analysis in two experienced laboratories. FCM instruments, run conditions, and tumor disaggregation procedures were different in the two laboratories. In four cases (12%) the laboratories reported a different DNA ploidy and DNA index (DI). These variations were due to analytical reasons, differences in the detection rates of near-diploid and tetraploid DIs, not due to interpretation of data or the criteria used for aneuploidy. There was a significant correlation between S-phase fractions (SPF) obtained in the two laboratories (r = 0.90, p less than 0.0001) if only cases with concordant DI were included. Discordant DI usually led to very different SPF values.

Immunoelectron-microscopic localization of a proliferation-associated antigen Ki-67 in MCF-7 cells

Immunocytochemistry using the monoclonal antibody Ki-67 is a commonly used method to assess proliferative activity of malignant tumours, Ki-67 reacts with proliferating cells with an antigen, whose structure, function and exact locations are unknown. We studied the subcellular location of Ki-67 in MCF-7 cells using immunoelectron microscopy. In the interphase cells, Ki-67 immunoreactivity was localized in the nucleolus, mainly in the nucleolar cortex. In particular, areas of the granular component of the nucleolus were strongly stained. Weak spot-like nucleoplasmic immunostaining was also seen outside the nucleolus. During prophase Ki-67 antigen was localized on the surfaces of the condensed chromatin and during metaphase on the surface of the chromosomes. After cell division and prior to formation of new nucleoli, Ki-67 immunoreactivity was located in the nucleoplasm. Quantification of Ki-67 immunofluorescence signal by flow cytometry revealed highest Ki-67 levels in mitotic cells. The location of Ki-67 is very similar to certain recently described proteins of nucleolar preribosomes suggesting that Ki-67 may also be a component of the preribosomes.

Lipoprotein metabolism of human and rabbit arterial cells in primary culture

The early atherosclerotic lesion, the fatty streak, consists of cholesteryl ester-containing foam cells originating mainly from monocyte-macrophages and to a lesser extent from smooth muscle cells. In this study, we describe lipoprotein uptake and cholesterol accumulation into enzyme-dispersed primary cell cultures from cholesterol-fed rabbit aortas and human aortic fatty streaks. Uptake of fluorescently labelled acetylated low density lipoprotein (acetyl-LDL) was demonstrable in macrophage-derived foam cells and in many smooth muscle cells in early primary cultures. The uptake of acetyl-LDL led to significantly enhanced cellular esterification of cholesterol. Fluorescent beta-migrating very low density lipoprotein (beta-VLDL) was internalized by a considerable number of lesion macrophages and also by smooth muscle cells. Also beta-VLDL uptake stimulated cholesterol esterification, although the effect was milder than that of acetyl-LDL. These findings lend support to the assumption that, during atherogenesis, arterial macrophages are capable of accumulating cholesteryl esters by receptor-mediated uptake of beta-VLDL and modified LDL. The internalization of modified LDL by smooth muscle cells represents a mechanism potentially contributing to the formation of foam cells in the atherosclerotic lesion.

Prognostic factors in recurrent breast cancer: relationships to site of recurrence, disease-free interval, female sex steroid receptors, ploidy and histological malignancy grading

Site of first recurrence, disease-free interval (DFI), female sex steroid receptors, ploidy measurements as well as histological grading have been analysed as potentially valuable predictive factors in 313 cases of recurrent breast cancer. Univariate and multivariate analyses show histological grading, site of recurrence and disease free interval to be useful prognostic variables when assessing prognosis once disease has recurred. High concentrations of oestrogen receptors (ER) were found in patients with bone metastases, whereas lower concentrations of ER were related to visceral recurrences. Ploidy measurements failed in this study to give any predictive information once disease recurred.

Evaluation of cell proliferation in breast carcinoma. Comparison of Ki-67 immunohistochemical study, DNA flow cytometric analysis, and mitotic count

Growth kinetics of 102 breast carcinomas were studied by immunohistochemical analysis with the monoclonal antibody Ki-67, which reacts with a nuclear antigen in proliferating cells. The results were correlated with ploidy and S-phase fraction (SPF) analyzed by DNA flow cytometric study and with mitotic count analyzed by light microscopic study. The proportion of Ki-67-positive cells (Ki-67 score) in breast carcinomas varied from 0.6% to 80% (median, 6.3%). Ki-67 scores were significantly higher in the DNA aneuploid than in the DNA diploid tumors. Ki-67 scores correlated significantly with tumor SPF in DNA aneuploid tumors. In DNA diploid tumors SPF showed no correlation with Ki-67 score. High Ki-67 scores were associated with high mitotic counts (P less than 0.0001) and histologic grade (P less than 0.0001). Nuclear pleomorphism, tubule formation, or lymph node status were not correlated with Ki-67 score. In conclusion, Ki-67 immunostaining correlates with other measures of cell proliferation (SPF, mitotic count) supporting its clinical significance.