Practical breast carcinoma cell kinetics: review and update

The proliferation rate paradox in antimitotic chemotherapy

Cytotoxic cancer chemotherapy drugs are believed to gain selectivity by targeting cells that proliferate rapidly. However, the proliferation rate is low in many chemosensitive human cancers, and it is not clear how a drug that only kills dividing cells could promote tumor regression. Four potential solutions to this “proliferation rate paradox” are discussed for the microtubule-stabilizing drug paclitaxel: drug retention in tumors, killing of quiescent cells, targeting of noncancer cells in the tumor, and bystander effects. Testing these potential mechanisms of drug action will facilitate rational improvement of antimitotic chemotherapy and perhaps cytotoxic chemotherapy more generally.

Prognostic/Predictive Factors in Breast Cancer

This can be an exciting time for pathologists and cytopathologists as we refine or knowledge of prognostic/predictive factors in breast cancer. We can become more visible in our role as consultants to the other physicians, and more engaged in our role as re-searchers. Recent advances in computer science, coupled with the availability of new biological markers, now provide unique opportunities for us to expand our diagnostic abilities and also predict the biologic behavior of a given tumor. Thus, we must become more familiar with emerging concepts and technologies in different disciplines.

Prognostic and predictive factors in the adjuvant treatment of breast cancer

The selection of systemic adjuvant therapy should be based on the appropriate prognostic and predictive factors. The established prognostic factors currently used in cases of primary breast cancer include axillary lymph node involvement, histologic subtype, tumor size, nuclear or histologic grade, estrogen (ER) and progesterone receptor (PR) status and proliferative index. Adjuvant chemotherapy has had an impact on the management of node-positive breast cancer, while the St. Gallen recommendations were established for postoperative adjuvant therapy for node-negative breast cancer. However, there is some contention regarding the histological (or nuclear) grading systems among different pathologists. With regard to biological measurements, the most useful prognostic/predictive factors are hormone receptor status and HER-2 overexpression. ER and PR status can be used to establish the necessity of hormone therapy in the adjuvant setting. If the anti-HER-2 antibody and/or antiangiogenic agents are introduced into the adjuvant setting in the near future, determination of these factors is also recommended.

Down-regulation of insulin-like growth factor-I receptor and insulin receptor substrate-1 expression in advanced human breast cancer

The ligands, receptors and related signaling proteins of the insulin-like growth factor family are involved in the regulation of breast-cancer cell growth. We investigated the expression pattern of insulin-like growth factor-I receptor (IGF-IR), insulin receptor (IR) and insulin receptor substrate-1 (IRS-1), a core downstream signaling protein, in 69 primary breast-cancer specimens of different grades and in 21 control tissues by immunohistochemistry. In addition, cell proliferation (percentage of Ki67(+) nuclei) and estrogen receptor (ER) expression were determined. IGF-IR, IRS-1 and IR were expressed mainly in epithelial cells. IRS-1 and IGF-IR were expressed at high levels in control tissues and in well and moderately differentiated carcinomas but at low levels in poorly differentiated breast cancers. IR expression did not show a significant correlation with the differentiation grade of the tissues investigated. Statistical analysis (ROC analysis for tumor grade) demonstrated that down-regulation of IGF-IR and IRS-1 correlated better with tumor progression than reduction of ER expression or increase in cell proliferation, IGF-IR showing the best correlation, followed by IRS-1 and, less significant, ER and Ki67. Our findings clearly show that progression of breast cancer is accompanied by a reduction of IGF-IR/IRS-1 expression and that IGF-IR/IRS-1 expression inversely correlates with high proliferation rate in dedifferentiated breast cancers. The strong correlation of IGF-IR and IRS-1 down-regulation with tumor progression suggests the use of IGF-IR and IRS-1 as a novel set of marker proteins for tumor grading.

Ploidy analysis by in situ hybridization of interphase cell nuclei in fine-needle aspirates from breast carcinomas: correlation with cytologic grading

Fine-needle aspirates from 54 breast cancer patients were investigated for numeric aberrations in chromosomes 6, 7, 12, and 17 by in situ hybridization (ISH) of interphase cell nuclei. Ploidy findings were compared with cytologic grading of tumors. Aneuploidy was found in 73% of cases. Chromosomes 6 and 7 showed numeric abnormalities in 63% and 62% of cases, respectively, whereas chromosome 17 retained a disome pattern in 2/3 of the tumors. Thirteen cancers (28% of 47 with four analyzed probes) had a normal signal number in all four chromosomes. In 17 (36%), all four had signal gain. Another 17 showed a mixed disome/aneusome pattern. They presented a continuum of increasing numeric abnormalities, 82% disomy for chromosome 17, and 13 of them were grade 2, indicating intermediate biologic properties. Correlation between grading and ploidy was good, with 10 of 11 grade 1 carcinomas showing diploidy, whereas 33 of 36 grade 2 and 3 tumors had numeric aberrations.

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.

Proliferation of the breast epithelium in relation to menstrual cycle phase, hormonal use, and reproductive factors

The proliferative rate in normal breast epithelium from 58 women undergoing reduction mammoplastics was studied using the formalin resistant antibody Ki-S5, and related to age at operation, menstrual cycle phase, family history of breast cancer, height and weight, parity, and hormonal use. The breast tissue from women operated on in the luteal menstrual cycle phase (day 15-28 among oral contraceptive (OC) users) had significantly higher proliferative rate than breast tissue removed from women in the follicular phase (day 1-14) (p = 0.01). Among women presently exposed to hormones, those with a positive family history of breast cancer among first and second degree relatives had significantly higher values than cases without such history (p = 0.02). Weight was not significantly related to proliferation rate, while a short height was associated with a significantly higher proliferation rate (p = 0.04). Women who used OCs before the first full-term pregnancy (FFTP) had a significantly higher proliferation rate compared with never users or late users (p = 0.04). No significant difference was seen between parous versus nulliparous women. The results from the univariate analysis persisted in multivariate models. An especially high proliferation rate was seen in young women with both a positive family history and present hormonal use (p = 0.001). Overall, it was found that young women had a non-significantly higher proliferation rate than older women (p = 0.10). Due to small sample size, these results must be regarded as preliminary, especially in the subgroup analyses.

Relationship between low estrogen receptor values and other prognostic factors in primary breast tumors

BACKGROUND

The current study compared the immunocytochemical expression of estrogen (ER) and progesterone (PgR) receptors by malignant breast cells to the hormone receptor concentrations reported from radioligand assays. These values were examined in relation to DNA ploidy and the fraction of cells in S phase.

METHODS

ER and PgR concentrations, DNA ploidy, and S-phase fractions were measured by standard techniques with 124 samples of invasive ductal carcinoma. Suspensions of tumor cells were examined by immunocytochemical assay (ICA) for the percentages of ER and PgR positive cells.

RESULTS

Twenty-six of the 38 tumors from patients 50 years of age or younger were classified as high S-phase fraction, and 28 tumors had aneuploid levels of DNA. The 20 ER positive tumors each contained less than 100 fmol/mg. Thirty-nine of the 86 tumors from patients older than 50 years were classified as high S phase, and 41 were aneuploid. Sixty-five samples were considered ER positive by radioligand assay. ICA showed that tumors in either age group with less than 40 fmol/mg did not contain ER positive cells. The proportion of samples with PgR levels between 10 and 100 fmol/mg was small, and fewer PgR positive tumors were categorized as negative when examined by ICA for receptor containing cells. The reclassification of the hormone receptor status of a tumor based on ICA appeared to be independent of S-phase and ploidy values.

CONCLUSIONS

Tumors that are classified as ER or PgR positive based on accepted cutoff values for radioligand assays may actually be receptor negative because the tumors do not appear to contain receptor positive cells.

Prognostic value of the combined assessment of proliferating cell nuclear antigen immunostaining and nuclear DNA content in invasive human mammary carcinomas

The expression of the S-phase associated, nuclear protein proliferating cell nuclear antigen (PCNA) was investigated in routinely paraffin-embedded surgical specimens from 209 breast cancer patients. Cytometric DNA assessments were performed on fine-needle aspirates, upon which the primary diagnosis of breast cancer had been based. The mean clinical follow-up was 16 years (range 13-20 years). The percentage of PCNA immunoreactive tumour cells ranged between less than 5 to 60% (mean value 13.34%). There was a direct association between PCNA expression, high histological tumour grade (p < 0.01), and DNA aneuploidy (p = 0.009). In a subgroup of 22 patients with near-diploid DNA distribution patterns the PCNA expression yielded additional prognostic information. Patients with tumours of near-diploid DNA histograms and more than 20% of PCNA immunoreactive neoplastic cells had a significantly worse clinical course, than patients with near-diploid tumours containing less than 20% PCNA immunoreactive cells (p = 0.0001). In contrast, the PCNA immunoreactivity did not yield additional prognostic information for patients with distinctly diploid or highly aneuploid tumour variants. In a multivariate analysis comprising all 209 patients, nodal status (p < 0.01), tumour size (p < 0.01), and DNA ploidy (p < 0.01) were found to have significant prognostic effect. The findings indicate that carcinomas characterised by high proliferative activity and near-diploid DNA distribution patterns can show rapid tumour progression. The combined assessment of the PCNA immunoreactivity and of the nuclear DNA content in routinely processed surgical specimens of breast cancer patients appears to be of prognostic value.

Prediction of early relapse and shortened survival in patients with breast cancer by proliferating cell nuclear antigen score

BACKGROUND

Cell cycle kinetic measures have been shown to have prognostic significance in breast cancer. Methods that have been used to assess the proliferating fraction of tumors include measurements of DNA content with S-phase calculation by flow cytometric analysis, radioisotope-labeled nucleotide incorporation, and cell cycle-associated protein expression. The recent discovery of the S-phase-specific nuclear protein proliferating cell nuclear antigen (PCNA) opens the door for a novel approach to cell kinetic measurement with an immunocytochemical assay.

METHODS

A quantitative immunocytochemical assay for PCNA was performed on 82 primary invasive breast carcinomas fixed in formaldehyde solution and embedded in paraffin and 18 corresponding axillary metastases. The percentage of tumor cells with strong nuclear staining was determined by visual count. This PCNA score was correlated with histologic parameters, age, relapse intervals, and long-term survival.

RESULTS

PCNA scores were distributed normally among primary carcinomas (range, 5-54; mean, 22.5). Carcinomas had much higher scores than adjacent normal epithelium (means, 22.5 and 4.1, respectively; P < 0.00001), and axillary node metastases had slightly higher scores than corresponding primary breast tumors (means 26.4 and 22.5, respectively; P = 0.05). The PCNA score did not correlate with age, tumor size, axillary node status, intramammary lymphatic-vascular invasion, or estrogen and progesterone binding capacities. Furthermore, its variability could not be explained by grade. PCNA values increased as the mitotic rate increased. Cancers with high PCNA scores (> or = 25) were associated with shorter disease-free (P = 0.007) and overall survival times (P = 0.01) than tumors with low PCNA scores (< 25) (median follow-up, 166 months).

CONCLUSIONS

PCNA score has potential value as a prognostic indicator in breast cancer. This method of assessing the proliferating pool offers advantages over other assays in terms of relative simplicity of the method, applicability to paraffin-embedded fixed tissue, and low cost.

Molecular aspects of early stages of breast cancer progression

It is clear that breast cancer progression is associated with inactivation of a number of different recessive oncogenes. The most widely evaluated tumor suppressor gene, p53, is mutated in approximately 30-50% of sporadic breast cancers. Mutations usually occur early in malignant progression. Loss of heterozygosity (LOH) studies have identified numerous chromosomal regions where other recessive oncogenes relevant to breast cancer may be located. Each LOH is seen in a varying proportion of breast cancers and may appear either early or late in progression. High-grade ductal carcinoma in situ (DCIS) and invasive carcinoma have similar genetic lesions, showing that aberrations can occur before invasive disease. Direct evidence that the same aberrations can be acquired later in progression comes from a study of multiple metastases from the same patient; other studies found that primary invasive cancers are characterized by marked intratumor heterogeneity for each lesion examined. The model we propose to account for these results hypothesizes that multiple genetic lesions can accomplish each phenotype required for malignancy (i.e., dysregulated proliferation, invasion, angiogenesis, etc.) and that, for a given tumor, at least one aberrant gene for each phenotypic change is stochastically selected. Biological heterogeneity of breast cancer results from the stochastic acquisition of various genetic aberrations. We further propose that the lymphocytic reaction in high-grade DCIS may select for aggressive tumor subpopulations capable of escaping immune surveillance. Another aspect of tumor heterogeneity may be the multiple mechanisms employed by various tumors to escape immune surveillance.

Biologic variations of tumors

Few tumors are so heterogeneous in their growth rates and patterns of metastasis as breast cancer. In general, the clinical phase of this disease is much longer than that of most other tumors. It is assumed that the preclinical phase is similarly long and this is one reason that the use of screening mammography has reduced breast cancer mortality. Mammography is not equally effective in all patient populations, but it has not yet been possible to precisely define those populations of women more or less likely to benefit from periodic mammography. Future studies should place greater emphasis on the correlation between frequency of mammography and biologic variations.

Prognostic potential of flow cytometric S-phase and ploidy prospectively determined in primary breast carcinomas

In a prospective study of a consecutive breast cancer series accumulated in the period 1978-82, the S-phase fraction (SPF) and ploidy status were determined by flow cytometry performed on cell nuclei derived from samples of 580 primary tumors. Sixty percent of the tumors were non-diploid. After correction for debris the median SPF values were 7.3% overall, 12% for non-diploid tumors, and 2.9% for diploid tumors (2.6% when nodal subsets N2 and N3 and cases with metastases at presentation were excluded). The SPF values correlated both to tumor size (p = 0.008) and to the number of positive axillary lymph nodes (p = 0.03). At clinical follow-up in 1986, 467 unilateral breast cancer patients who had undergone radical treatment for cure could be evaluated with respect to the prognostic value of both the SPF value and ploidy status. The median duration of follow-up was then 59 months (range 2-90), and the median time-to-recurrence 24 months (range 2-69, n = 137). At follow-up in 1991, 201/467 of the patients had died, the median duration of follow-up being 50 months (range 2-126) for the decreased, and 119 (range 6-148) for the survivors. In multivariate analysis (Cox's proportional hazards models), the strongest independent predictors of distant recurrence-free survival (DRFS) were the number of positive axillary lymph nodes (p less than 0.0001), the debris-corrected SPF value alone (p = 0.003, versus p = 0.05 for uncorrected value), and ploidy status combined with the corrected SPF value (p = 0.0002). When age was taken into account, both the corrected SPF value and the ploidy-SPF combination were predictors of crude survival (p = 0.006 and p = 0.002, respectively). In univariate life-table analysis, the 5-year DRFS rate was 93% in node-negative (N0) cases with an SPF less than 7.3%, as compared to 80% in those with an SPF greater than or equal to 7.3% (p = 0.005). Among node-positive cases, the prognostic value of the SPF was confined to those with 1-3 positive nodes, the 5-year DRFS rate being 68% in cases with an SPF less than 7.3%, as compared to 40% in cases with an SPF greater than or equal to 7.3% (p = 0.01).(ABSTRACT TRUNCATED AT 400 WORDS)

Breast cancer proliferation measured on cytological samples: a study by flow cytometry of S-phase fractions and BrdU incorporation

Cell kinetics have been shown to be an important predictor of clinical evolution of operated breast cancer. We established a method for the estimation of the proliferative activity of tumour cells obtained by fine needle sampling without aspiration (FNS), using simultaneously S-phase fractions (SPF) measured on DNA histograms and 5-bromodeoxyuridine (BrdU) labelling index (BLI) measured by flow cytometry. Biparametric BrdU/DNA flow cytometry could be performed in 122 of 189 (65%) consecutive patients. The mean BLI of the cytologically malignant FNS (118) was of 3.0 and the median of 2.2%. One hundred and forty-eight DNA histograms (78%) were suitable for SPF analysis, of which 141 presented malignant cells, showing a mean of 4.5 and a median of 3.5%, comparable to BLIs. These results were obtained from fluorescence peak area histograms with doublet discrimination and background subtraction allowing the measurements of SPFs as low as 0.4%. An excellent correlation was thus observed between BLIs and SPFs, for the 94 cases for which both results were available (r = 0.85). Infrequent discordances (9%) were noted with SPFs considerably higher than BLIs. Seven patients had three consecutive FNS of their tumour at weekly intervals before treatment. Some variability in the proportions of multiple subpopulations of tumour cells was observed on the DNA histograms. In contrast, proliferation indices (SPF or BLI) were reproducible, suggesting homogeneous growth rates. We conclude that an estimation of the proliferative activity of breast tumours at any stage of the disease is possible routinely by SPF and/or BLI analysis of FNS. At least one quantitative proliferation index could be obtained for 91% of patients.

Proliferation and DNA ploidy in malignant breast tumors in relation to early oral contraceptive use and early abortions

In 175 premenopausal breast cancer patients, a history of oral contraceptive (OC) use before 20 years of age was significantly associated with higher tumor cell proliferative activity, as indicated by a higher S-phase fraction (SPF), and a higher fraction of DNA aneuploid tumors, compared with later or never users (P = 0.05 and p = 0.01, respectively). The higher SPF among early OC users was apparent in patients with aneuploid tumors but not in patients with euploid tumors. Abortions (spontaneous or induced) before the first full-term pregnancy also were associated with a higher SPF compared with other young patients with breast cancer (P = 0.03). Adjusting for parity and abortions or OC use, respectively, an early OC use was associated with a 43% higher SPF and early abortions were associated with 49% higher SPF. Younger patients had a higher SPF and a higher frequency of aneuploid tumors, but this was found to be because the users of OC had a lower median age at diagnosis. Among never users, no significant age relationship was seen for SPF or the frequency of aneuploidy. For the DNA analyses there is a selection of patients with breast cancer with larger tumors, and therefore the conclusions drawn in this article may not be generalizable to patients with smaller primary tumors, e.g., cases diagnosed at breast cancer screening. The higher tumor proliferative activity and frequency of aneuploidy in early OC users are in line with previously reported findings of worse prognostic indicators and a worse survival in early users of OC compared with other young women with breast cancer.

Immunohistochemical demonstration of cell proliferation and estrogen receptor status in human breast cancer. Analysis of 45 cases

Cell proliferation and estrogen receptor (ER) status was investigated in 45 invasive ductal carcinomas of the breast by immunohistochemical methods using monoclonal antibodies Ki-67 (anti-human proliferating cell antibody) and ER-ICA. The results were assessed on the basis of nuclear staining intensity and the percentage of positively stained tumor cell nuclei (index score). There was a significant inverse correlation between the Ki-67 and ER-ICA index scores, although 4 cases showed high index scores for both markers. We conclude that ER-positive cells do not always have low proliferation activity, which may be one of the reasons why endocrine therapy is not effective against all ER-positive breast cancers.

Breast cancer cytogenetics and beyond

It is hypothesized that cancers arise as a result of genetic or chromosomal alteration. Evidence for this is provided by the leukaemias and lymphomas in which cytogenetic studies are of established value in diagnosis, classification and follow-up. In contrast, the cytogenetic study of all solid tumours, including breast carcinoma, is in its infancy. However, cytogenetic studies indicate that clonal structural alterations do occur, affecting several loci on a number of chromosomes. Molecular studies provide further evidence of recurring chromosomal breakpoints in breast cancer. This paper reviews the chromosomal rearrangements observed to date and discusses their relevance to the biology of breast cancer.

Pathologic findings from the National Surgical Adjuvant Breast and Bowel Projects (NSABP). Prognostic discriminants for 8-year survival for node-negative invasive breast cancer patients

Twenty-two pathologic features (including estrogen and progesterone receptors) and four clinical features observed in 950 women with node-negative Stage I invasive breast cancer who enrolled in the National Surgical Adjuvant Breast and Bowel Projects (NSABP) protocol B-06 were evaluated for their possible prognostic significance. Preliminary univariate analysis revealed ten characteristics that were significant in this regard at the 1% level. Their assessment in a Cox regression model demonstrated only three to be prognostically important; notable among these were nuclear grade, histologic tumor type, and race. Life-table plots revealed that 86% of patients whose cancers exhibited good nuclear grade survived for 8 years as opposed to 64% in whom the nuclear grade was scored as poor. Analyses demonstrated three prognostic categories for histologic tumor type. Patients with either mucinous, tubular, or papillary cancers fared significantly better than those having not otherwise specific (NOS) or atypical medullary tumors. Survival for those with typical medullary, NOS combinations, or lobular invasive cancers was intermediate. Blacks fared worse than whites. Survival was correspondingly better or worse when two favorable or unfavorable characteristics were detected. The number of black women in this cohort was considered too small for further subset analysis although generally the pattern of findings suggested that survival was worse for blacks than for whites in all subsets. A review, as well as our own experience, suggested that nuclear grade is as good if not better as a predictor of survival in node negative patients as information derived from DNA analyses, immunohistochemical demonstration of erb-B2 overexpression, and, possibly, the tumor labeling index at predicting survival in node-negative patients.

Indicators of prognosis in node-negative breast cancer

Measures of the proliferative activity of tumor cells have prognostic value in patients with node-negative breast cancer. We studied 367 women in southern Sweden who had undergone surgical resection for such cancer. Tumor specimens were analyzed with DNA flow cytometry in order to estimate both the DNA content (ploidy) and the fraction of cells in the synthetic phase of the cell cycle (S phase). The median duration of follow-up was four years; 28 percent of the patients received adjuvant therapy, usually with tamoxifen (n = 83). A multivariate analysis based on complete data on 250 patients included the following covariates: age (greater than or equal to 75, 50 to 74, and less than or equal to 49 years), tumor size (less than or equal to 20 vs. greater than 20 mm), concentration of estrogen and progesterone receptors (less than 10 vs. greater than or equal to 10 fmol per milligram of protein), ploidy (diploid vs. nondiploid), and S-phase category (fraction of cells in S phase: less than 7.0 percent, 7.0 to 11.9 percent, and greater than or equal to 12 percent). The S-phase fraction yielded the most prognostic information, followed by progesterone-receptor status and tumor size. A prognostic model based on these three variables identified 37 percent of the patients as constituting a high-risk group with a fourfold increased risk of distant recurrence. In the remaining 63 percent of the patients, the five-year overall survival rate (92 +/- 4 [+/- SE] percent) did not differ from the expected age-adjusted rate for Swedish women. We conclude that a prognostic index that includes indicators of the proliferative activity of tumor cells may be able to identify women with node-negative breast cancer in whom the risk of recurrence is sufficiently low that adjuvant chemotherapy can be avoided.

Is DNA ploidy an independent prognostic indicator in infiltrative node-negative breast adenocarcinoma?

To evaluate DNA content as an independent, long-term prognostic indicator in infiltrative, node-negative adenocarcinoma of the breast, flow cytometric DNA analyses were performed retrospectively in 165 patients. The exclusive use of paraffin-embedded tissue permitted the study of patients for whom 3 to 15 years' follow-up was available. Other investigators have shown a relationship between DNA nuclear content and well-known prognostic indicators of breast carcinoma, such as estrogen receptors, age, menopausal status, and stage of tumor. However, very few of these studies were based on patients with long-term clinical follow-up and investigated the independent prognostic value of DNA nuclear content. The frequency of aneuploidy in the patients in this study was 57%, with DNA indices ranging from 0.73 to 2.59. Survival in patients with localized breast carcinoma with DNA aneuploid tumors was 84.1% at 5 years and 75.5% at 10 years. Those with diploid tumors showed survival of 87.8% at 5 years and 73.4% at 10 years. These data show no independent prognostic value for DNA nuclear content. The relationship between DNA content, tumor histologic type, and age was also investigated. High-grade tumors were more often aneuploid. There was no association between DNA content and age. Of 165 patients, information regarding estrogen receptor status was available in only 77; 45% of those with aneuploid tumors and 35% with diploid tumors were estrogen receptor-negative. This difference was not significant. The authors conclude that simple determination of DNA ploidy fails to indicate prognosis for infiltrative, node-negative breast carcinoma.

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.

Growth factors and oncogenes in breast cancer

The growth of normal breast epithelial cells is regulated by a complex interacting system of polypeptide factors and by steroid hormones. The cells respond to these factors through receptors which generate mitogenic and other intracellular signals. These second messengers provoke complex responses which may ultimately result in DNA replication and cell division. A comparison of normal cells and tumour cells, either in culture or from primary tumour biopsies, has revealed differences in growth factor and growth factor receptor expression. Such changes may represent aspects of the process of malignant transformation. In addition some evidence suggests that changes in second messenger systems may also occur. Finally several changes in nuclear oncogenes have been observed in breast cancers. It has been proposed that changes in the nuclear oncogenes, perhaps involving the loss of function of tumour suppressor genes, may allow cells to enter the cell cycle. Changes in growth factors, their receptors or intracellular second messenger systems may stimulate unregulated growth. The combination of these events provide a model for the process of carcinogenesis.

Influence of S-phase fraction on metastatic pattern and post-recurrence survival in a randomized mammography screening trial

Using static cytofluorometry, S-phase was determined on the primary tumors of 421 patients with breast carcinomas in stages I-III diagnosed 1981-85 during the second and third screening rounds of a randomized trial evaluating the effect of mammographic screening. Through December 1988, 82 patients had developed local and/or distant recurrence, 51 of whom had died of cancer during the same period. The distribution among sites of recurrence differed between patients with tumors detected by mammography screening and cancers diagnosed due to clinical symptoms. The mean S-phase fraction was highest in patients with liver or brain metastases and lowest in patients with metastases in subcutaneous and cutaneous tissue and lymph nodes only. In univariate analysis, survival after first recurrence was significantly associated with the site of primary recurrence, the disease-free interval, and node status and tumor size at diagnosis, as well as the S-phase level. The median survival period was 31.3. months for patients with a S-phase fraction below 6%, and 10.7 months in cases with S-phase exceeding 10%. Neither ploidy nor the estrogen receptor content had significant influence on post-recurrence survival. In Cox's multiple regression analysis, only metastatic site, disease-free interval, and S-phase fraction showed significantly independent prognostic value.

Prognostic value of estrogen and progesterone receptors in primary infiltrating ductal breast cancer. A sequential multivariate analysis of 1262 patients

Nine prognostic variables were evaluated for their significance in predicting the overall survival (OS), the length of disease-free survival (DFS) and the length of metastasis-free survival (MFS) of 1262 patients with primary breast cancer. The variables studied were: UICC clinical stage; menopausal status; histologic grade; number of involved nodes; anatomic tumor size; estrogen and progesterone receptors; local and adjuvant therapies. Three sequential multivariate analyses, at 2, 5 and 10 years, using the Cox proportional hazard regression model, were carried out to identify those variables most highly related to the criteria studied (overall, disease-free, metastasis-free survivals) and especially to fully evaluate the effects of hormonal receptors on prognosis and their stability over time. Our results showed that number of involved nodes and histologic grade were the most significant prognostic factors for all periods of time and whatever the criterion studied; ER had no predictive value while PR was an independent prognostic factor for metastasis-free survival at 2 years (P = 0.01) and 5 years (P = 0.02) but lost its significance at 10 years (P = 0.06). In the subgroup of 261 patients who received prolonged post-operative adjuvant chemotherapies, PR was the main prognostic factor for MFS at 2 years (P = 0.03) and the second at 5 years (P = 0.05) just after number of involved nodes. In the 1001 patients who did not receive prolonged post-operative adjuvant chemotherapies ER was significant for MFS at 5 and 10 years. The present data urge the need for a periodic redefinition of prognostic factors in primary breast cancer.

Colony forming ability of human breast carcinomas: lack of prognostic significance

To study whether colony growth in vitro reflects the prognosis of breast cancer patients, specimens from a total number of 138 patients with primary breast carcinomas were cultivated in the Courtenay-Mills soft agar method. The plating efficiency (PE) values were related to various clinical and histopathological parameters. No significant correlation was found between colony forming ability and menopausal status, histopathology, TNM-status or steroid hormone receptor status. The crude survival of the patients was not significantly correlated to the in vitro growth of the tumours; neither was there any difference in relapse-free survival between patients whose tumours failed to grow in vitro and those having growing tumours (PE greater than 0). A multivariate survival analysis of 115 patients with primary tumours without distant metastases revealed that the PE was not a significant independent prognostic indicator, as it gave no additional prognostic information above that of node and ER status. It is concluded that routine measurement of colony formation in vitro is not warranted in the management of breast cancer.

Prognostic parameters in breast cancer

Carcinoma of the breast is the most common cancer in Australian women. Current methods of treatment and refinements in therapeutic regimens are based on our understanding of the biological behaviour of the disease. Several prognostic parameters have been identified which predict survival and allow the selection of patients who may benefit from adjuvant therapies. The more important of these parameters include tumour size, histologic type, histologic grade, axillary lymph node status, estrogen receptor status and tumour growth fraction. Diagnostic pathologists who are responsible for the evaluation of these parameters should be cognizant of their relative prognostic values and also of other factors such as cellular antigens, lectin binding and oncogenes which may have potential roles in predicting survival and therapeutic responses. This review provides an update of prognostic parameters which are assessed through examination of the excised specimen.

Cell proliferation kinetics in human solid tumors: relation to probability of metastatic dissemination and long-term survival

A large number of studies have investigated the relationship between the long-term survival and the percentage of tumor cells in S phase assessed by autoradiography after tritiated thymidine labelling, image cytometry, flow cytometry or labelling with an halogenated analog of thymidine, in various types of human solid tumors. The survey of the results clearly shows that the S-phase fraction (SPF) is of high prognostic significance in several types of cancers, in particular in breast cancers, non-Hodgkin lymphomas, ovarian cancers, neuroblastoma, bladder cancers and lung cancers. SPF was found of high independent significance in 10 of the 11 studies in which multivariate analyses of prognostic factors had been carried out. Proliferation appears generally to be of higher prognostic significance than ploidy. In view of the wide differences in the biological characteristics of the tumors studied, it is likely that the association between a high proliferation rate and the degree of tumor aggressiveness is a general feature of human solid tumors. However, high proliferative rate of tumor cells is probably not the cause of tumor biological aggressiveness but a variable associated with it. The extent to which cells escape from the regulatory systems which control their proliferation appears to be a good index of tumor progression.

Cell dissociation techniques in human breast cancer--variations in tumor cell viability and DNA ploidy

Approximately 70% of breast cancers contain cell populations with hyperdiploid (greater than G0/G1) DNA content; however, cells cultured from breast cancers have only diploid DNA contents and karyotypes. Mechanically dissociated cells rarely, if ever, grow in culture, while enzymatically dissociated cells do grow in most cases. To determine if cell dissociation techniques used to prepare cells for culture and other laboratory procedures select for cells with specific features, and if tumor cells are killed in the process, breast cancer cells obtained by mechanical dissociation and by enzymatic dissociation were examined for DNA content and cell viability (measured by dye exclusion). Mechanical dissociation yielded more dead cells and cells with hyperdiploid (greater than G0/G1) DNA than did enzymatic dissociation. Hyperdiploid cells were also found in the dye-excluding population with each dissociation technique, suggesting that the hyperdiploid cells were not always dead. We conclude that, in vivo, tumors contain cellular subpopulations with low viability and hyperdiploid (greater than G0/G1) DNA patterns. The extent to which these subpopulations are present in a sample depends on the dissociation technique employed. That only diploid cells are found in cultures of primary breast cancers may be because enzymatic dissociation, used to prepare cells for culture, yields predominantly diploid cells. These observations also have important implications for interpreting measurements made on dispersed cells, e.g., viability, DNA content, and other cytochemical markers.

A general native-state method for determination of proliferation capacity of human normal and tumor tissues in vitro

An important need in cancer research and treatment is a physiological means in vitro by which to assess the proliferation capacity of human tumors and corresponding normal tissue for comparison. We have recently developed a native-state, three-dimensional, gel-supported primary culture system that allows every type of human cancer to grow in vitro at more than 90% frequency, with maintenance of tissue architecture, tumor-stromal interaction, and differentiated functions. Here we demonstrate that the native-state culture system allows proliferation indices to be determined for all solid cancer types explanted directly from surgery into long-term culture. Normal tissues also proliferate readily in this system. The degree of resolution of measurement of cell proliferation by histological autoradiography within the cultured tissues is greatly enhanced with the use of epi-illumination polarization microscopy. The histological status of the cultured tissues can be assessed simultaneously with the proliferation status. Carcinomas generally have areas of high epithelial proliferation with quiescent stromal cells. Sarcomas have high proliferation of cells of mesenchymal organ. Normal tissues can also proliferate at high rates. An image analysis system has been developed to automate proliferation determination. The high-resolution physiological means described here to measure the proliferation capacity of tissues will be important in further understanding of the deregulation of cell proliferation in cancer as well as in cancer prognosis and treatment.

Factors affecting relapse in node-negative breast cancer. A multivariate analysis including the labeling index

Between 1975 and 1982, 167 patients with carcinoma of the breast without axillary lymph node metastases were studied. The thymidine labeling index (LI), representing the percentage of cells in the DNA synthesis phase, was measured in all these patients. High LI values were more frequently encountered in young patients (P = 0.05), in low estrogen receptor (ER) tumor content (P = 0.007) and in high grade tumors (P = 0.0002). The overall 8-year relapse-free survival (RFS) was 68%. Univariate analysis demonstrated that RFS was influenced by histological grading (P = 0.03), ER (P = 0.03), PR (P = 0.02) and LI (P = 0.01). Multivariate analysis using the Cox regression model selected the LI as the single significant prognostic factor with regard to RFS (P = 0.037). These results emphasize the important role of cell proliferation kinetics in defining node-negative breast cancer patients with a high risk of relapse.

Reproductive events, occurring in adolescence at the time of development of reproductive organs and at the time of tumour initiation, have a bearing on growth characteristics and reproductive hormone regulation in normal and tumour tissue investigated decades later--a hypothesis

Both animal and human data indicate that reproductive events taking place early in reproductive life may have an important influence on growth characteristics and reproductive hormone regulation in both normal tissue and neoplastic tissue investigated later in life.

Prognostic factors in breast cancer

There are several independent but interrelated prognostic factors predictive of recurrence and survival in breast cancer. These include axillary nodal status, histopathology, steroid receptors, proliferative rate, ploidy, and oncogene amplification. Axillary nodal status has been the traditional mainstay predictor for recurrence and survival in primary breast cancer. In addition, the presence of the estrogen and progesterone receptors has correlated with longer disease-free interval and overall survival in stage I and II breast cancer. Thymidine-labeling index and percent S-phase as measured by flow cytometry are indices of cell proliferation that correlate with relapse rate in pre- and postmenopausal women with breast cancer. Estrogen and progesterone receptor-negative tumors are more commonly aneuploid, and have higher percent S-phase, factors that predict for recurrence in Stage I breast cancer.

Improving the prognostic value of DNA flow cytometry in breast cancer by combining DNA index and S-phase fraction. A proposed classification of DNA histograms in breast cancer

To optimize the prognostic value of DNA flow cytometry in breast cancer the authors calculated several parameters from the DNA histogram, including the DNA index, the size and number of aneuploid peaks as well as S-phase and G2/M-phase cell cycle fractions. Of these, DNA index and S-phase fraction (SPF) proved to be the most valuable prognostic indices. DNA aneuploidy was associated with a three-fold risk of death as compared to DNA diploidy (P less than 0.0001). The highest risk of death was associated with hypertetraploid (greater than 2.20) DNA index, whereas a tetraploid DNA index (1.80-2.20) was associated with a relatively low risk. The SPF had significant additional prognostic value in both DNA diploid (P = 0.0002) and DNA aneuploid (P = 0.02) tumors. By combining DNA index and SPF the authors defined three types of DNA histograms, which were associated with favorable, intermediate, and poor prognosis of the patients. DNA diploidy together with low (less than 7%) SPF (type I DNA histogram) was associated with very favorable prognosis, whereas DNA aneuploidy with high DNA index (greater than 2.20) or high (greater than 12%) SPF (type III DNA histogram) was related to the worst prognosis with approximately eight-fold relative risk of death. In a Cox multivariate regression analysis the type of DNA histogram was an independent and most powerful prognostic indicator in breast cancer. The other independent factors in the Cox analysis were primary tumor size, nodal status, and progesterone receptor status.

Apocrine carcinoma of the breast--a case report

A case of apocrine carcinoma of the breast is reported herein. Apocrine carcinoma is a rare tumor characteristically composed of large cells with eosinophilic cytoplasm. This case involves a 34-year old woman who underwent a modified radical mastectomy and is now doing well with no evidence of recurrence, 10 months after her surgery.

Isolation of the human anionic glutathione S-transferase cDNA and the relation of its gene expression to estrogen-receptor content in primary breast cancer

The development of multidrug resistance in MCF7 human breast cancer cells is associated with overexpression of P-glycoprotein, changes in activities of several detoxication enzymes, and loss of hormone sensitivity and estrogen receptors (ERs). We have cloned the cDNA for one of the drug-detoxifying enzymes overexpressed in multidrug-resistant MCF7 cells (AdrR MCF7), the anionic isozyme of glutathione S-transferase (GST pi). Hybridization with this GST pi cDNA, GST pi-1, demonstrated that increased GST pi activity in AdrR MCF7 cells is associated with overexpression but not with amplification of the gene. We mapped the GST pi gene to human chromosome 11q13 by in situ hybridization. Since multidrug resistance and GST pi overexpression are associated with the loss of ERs in AdrR MCF7 cells, we examined several other breast cancer cell lines that were not selected for drug resistance. In each of these cell lines we found an inverse association between GST pi expression and ER content. We also examined RNA from 21 primary breast cancers and found a similar association between GST pi expression and ER content in vivo. GST pi mRNA content in 11 ER-positive tumors (less than or equal to 10 fmol/mg of protein) was significantly different from the GST pi content of 10 ER-negative tumors (P = 0.002; Mann-Whitney Wilcoxon test for two independent samples). The finding of similar patterns of expression of a drug-detoxifying enzyme and of ERs in vitro as well as in vivo suggests that ER-negative breast cancer cells may have greater protection against antineoplastic agents conferred by GST pi than ER-positive tumors.

Steroid receptors, cellular kinetics, and lymph node status as prognostic factors in breast cancer

Steroid receptor status, cellular kinetics, abnormal proto-oncogene presence, and lymph node metastases all have been shown to provide prognostic information in breast cancer. The factors guide the choice of therapy and predict the course of the disease. Both disease-free survival and overall survival are predicted by these variables. Steroid receptors are the most reliable predictor of hormonal responsiveness. Lymph node involvement is crucial in determining the extent of the disease and the need for adjuvant therapy. Cellular kinetics and abnormal proto-oncogene presence predict tumor aggressiveness. Together these prognostic factors provide considerable information to the clinician.

DNA flow cytometry and prognostic factors in 1331 frozen breast cancer specimens

Breast cancer proliferative capacity as determined by the DNA thymidine labeling index, along with estrogen and progesterone receptor status, is highly predictive for risk of relapse and overall survival. Recently, DNA ploidy and proliferative capacity (S-phase fraction [SPF]) as determined by flow cytometry have also shown significant prognostic value. The authors have developed a technique which allows a 50 to 100 mg aliquot of the same frozen breast tumor specimen routinely employed in steroid receptor assays, to be assayed for both DNA ploidy and SPF by flow cytometry. Of the 1331 tumors examined, DNA histograms were evaluable for ploidy in 89% (1184) of specimens examined; 57% of these were aneuploid. Adapting a trapezoidal model to estimate SPF in both diploid and aneuploid tumors, the authors found 81% (1084) to be evaluable for SPF, with a median SPF of 5.8% for the entire population. The median SPF was significantly lower in diploid tumors (2.6%) than in aneuploid tumors (10.3%, P less than 0.0001). Both aneuploidy and high SPF were strongly associated with absence of steroid receptors. Aneuploid tumors showed more striking differences in the frequency of high S-phase values with respect to receptor status and age or menopausal status, whereas diploid but not aneuploid tumors showed lower SPF in node-negative versus node-positive patients. Because it is particularly important to identify the high-risk minority of node-negative patients, the authors examined the node-negative group separately. High SPF subgroups appeared in each category of receptor status and age or menopausal status within the node-negative group, suggesting that SPF will be an independent prognostic factor. With the DNA flow cytometric methods used here, it is now practical to determine ploidy and SPF for nearly every breast cancer patient. These factors, which show associations with established prognostic factors, such as receptor status can now be fully evaluated for their prognostic significance in broad patient populations.