Overview of the Biologic Markers of Breast Cancer

p53 codon 72 polymorphism and breast cancer risk: A meta-analysis

p53 is a tumor suppressor gene and plays important roles in the etiology of breast cancer. Studies have produced conflicting results concerning the role of p53 codon 72 polymorphism (G>C) on the risk of breast cancer; therefore, a meta-analysis was performed to estimate the association between the p53 codon 72 polymorphism and breast cancer. Screening of the PubMed database was conducted to identify relevant studies. Studies containing available genotype frequencies of the p53 codon 72 polymorphism were selected and a pooled odds ratio (OR) with 95% confidence interval (CI) was used to assess the association. Sixty-one published studies, including 28,539 breast cancer patients and 32,788 controls were identified. The results suggest that variant genotypes are not associated with breast cancer risk (Pro/Pro + Arg/Pro vs. Arg/Arg: OR=1.016, 95% CI=0.931–1.11, P=0.722). The symmetric funnel plot, Egger’s test (P=0.506) and Begg’s test (P=0.921) were all suggestive of the lack of publication bias. This meta-analysis suggests that the p53 codon 72 Pro/Pro + Arg/Pro genotypes are not associated with an increased risk of breast cancer. To validate the association between the p53 codon 72 polymorphism and breast cancer, further studies with larger numbers of participants worldwide are required.

P53 codon 72 polymorphism contributes to breast cancer risk: a meta-analysis based on 39 case-control studies

P53 is a tumor suppressor gene and plays important roles in the etiology of breast cancer. Studies revealing conflicting results on the role of p53 codon 72 polymorphism (G>C) on breast cancer risk led us to perform a meta-analysis to investigate this relationship. Thirty-nine published studies, including 26,041 breast cancer cases and 29,679 controls were identified. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the strength of the associations. The overall results suggested that the variant genotypes were associated with a significantly reduced breast cancer risk (GC vs. GG: OR = 0.91, 95% CI: 0.83-1.00; CC/GC vs. GG: OR = 0.90, 95% CI: 0.82-0.99). In the stratified analyses, significantly decreased risks were also found among European populations (GC vs. GG: OR = 0.89, 95% CI: 0.80-0.99; CC/GC vs. GG: OR = 0.88, 95% CI: 0.80-0.98) and studies with population-based controls (GC vs. GG: OR = 0.88, 95% CI: 0.78-0.98; CC/GC vs. GG: OR = 0.87, 95% CI: 0.78-0.97). The results suggested that p53 codon 72 polymorphism may contribute to susceptibility to breast cancer, especially in Europeans. Additional well-designed large studies were required to validate this association in different populations.

Establishment and characterization of new mammary adenocarcinoma cell lines derived from double transgenic mice expressing GFP and neu oncogene

A new murine cell line, named GFPneu, was established from a mammary adenocarcinoma arising in double transgenic MMTVneu x CMV-GFP mice. Breast tumours develop in 100% of females after 2 months latency, as a result of the over-expression of the activated rat neu oncogene in the mammary glands. All tissues, and in particular the breast tumours, express the GFP protein. This cell line was tumorigenic when inoculated into nude mice and the derived tumours showed the same histological features as the primaries from which they were isolated. Their histopathology reproduces many characteristics of human breast adenocarcinomas, in particular their ability to metastasize. The GFP marker allows us to visualize the presence of lung metastases in fresh tissues immediately, to confirm the histopathology. From a lung metastatic fluorescent nodule, we derived a further cell line, named MTP-GFP, which we also characterized. These two cell lines could be useful to study the role played by the neu oncogene in the maintenance of the transformed phenotype, in the metastatic process, to test novel therapeutic strategies to inhibit primary tumour growth and to observe the generation of distant metastases.

HER2 codon 655 polymorphism and risk of breast cancer in African Americans and whites

BACKGROUND

Several recent epidemiologic studies examined the association between breast cancer risk and an inherited, single-nucleotide polymorphism in the HER2 gene, codon 655 G to A, which leads to an amino acid substitution of Ile to Val. Results of previous studies have been mixed, with most studies showing no association but some suggesting an association in younger women or women with a family history of breast cancer.

METHODS

We conducted an association study of HER2 codon 655 genotype and breast cancer within the Carolina Breast Cancer study, a population-based, case-control study of in situ and invasive breast cancer in African American and white women in North Carolina. A total of 2015 cases and 1808 controls were genotyped.

RESULTS

We observed no overall association between HER2 genotype and breast cancer. However, a modest positive association (OR = 2.3, 95% CI 1.0-5.3) was observed for Val/Val + Ile/Val versus Ile/Ile genotypes in women age 45 or younger with a family history of breast cancer. Val/Val homozygotes were more common among cases with in situ versus invasive disease (P = 0.002). Breast tumors from women with Val/Val genotype were more likely to exhibit HER2 overexpression, but the results were not statistically significant (P = 0.17).

CONCLUSIONS

The HER2 codon 655 polymorphism may be one of many low-penetrant genes that make a minor contribution to breast cancer, particularly in subgroups of women. Additional large studies, as well as data pooling, will be needed to estimate the contribution of such genes to breast cancer risk.

Identification of HLA-A3-restricted CD8+ T cell epitopes derived from mammaglobin-A, a tumor-associated antigen of human breast cancer

Mammaglobin-A is highly overexpressed in breast cancer cell lines and primary breast tumors. This pattern of expression is restricted to mammary epithelium and metastatic breast tumors. Thus, mammaglobin-A-specific T cell immune responses may provide an important approach for the design of breast cancer-specific immunotherapy. The purpose of our study was to define the T cell-mediated immune response to mammaglobin-A. We determined that the frequency of mammaglobin-A-reactive CD8+ and CD4+ T cells in breast cancer patients is significantly higher than that observed in healthy female controls using limiting dilution analyses (p = 0.026 and p = 0.02, respectively). We identified 8 mammaglobin-A-derived 9-mer peptides with the highest binding affinity for the HLA-A3 molecule (Mam-A3.1-8) using a computer-assisted analysis of the mammaglobin-A protein sequence. Subsequently, we determined that CD8+ T cells from breast cancer patients reacted to peptides Mam-A3.1 (23-31, PLLENVISK), Mam-A3.3 (2-10, KLLMVLMLA), Mam-A3.4 (55-63, TTNAIDELK) and Mam-A3.8 (58-66, AIDELKECF) using an IFN-gamma enzyme-linked immunospot assay. A CD8+ T cell line generated in vitro against HLA-A*0301-transfected TAP-deficient T2 cells loaded with these peptides showed significant cytotoxic activity against the Mam-A3.1 peptide. This CD8+ T cell line showed a significant HLA-A3-restricted cytotoxic activity against mammaglobin-A-positive but not mammaglobin-A-negative breast cancer cells. In summary, our study identified four HLA-A3-restricted mammaglobin-A-derived epitopes naturally expressed by breast cancer cells, indicating the immunotherapeutic potential of this novel antigen for the treatment and prevention of breast cancer.

Rb localization and phosphorylation kinetics correlate with the cellular phenotype of cultured breast adenocarcinoma cells

Retinoblastoma protein (Rb) expression has been correlated with state of differentiation, proliferation rate, and metastatic potential in breast adenocarcinomas and established cell lines. These observations, based on immunoreactivity of total Rb rather than hypophosphorylated protein, do not address the relationship between functional Rb and indicators of an aggressive transformed cellular phenotype. We hypothesized that the distribution of functional Rb and the kinetics of Rb phosphorylation would differ between cell lines representing immortalized mammary epithelium (MCF10A), differentiated nonmetastatic mammary adenocarcinoma (MCF-7), and poorly differentiated, highly metastatic mammary adenocarcinoma (MDA-MB-231) and that these differences would be informative of the cellular phenotype. Direct immunofluorescence microscopy was used to compare qualitatively the subcellular localization of total and hypophosphorylated Rb protein in synchronized and asynchronous cells. This technique was also used to quantitatively assess the amounts of hypophosphorylated Rb throughout the cell cycle in these representative cell lines. Total Rb stained more prominently than hypophosphorylated Rb in the nucleus of all asynchronous cells. Rb phosphorylation was more rapid in MCF-7 cells than in MCF10A cells, whereas Rb dephosphorylation appeared deregulated in MDA-MB-231 cells. We conclude that assessment of hypophosphorylated Rb may be more useful than assessment of total Rb for the evaluation of transformed breast adenocarcinoma phenotypes.

Comparison of HER-2/neu oncogene amplification detected by fluorescence in situ hybridization in lobular and ductal breast cancer

BACKGROUND

Abnormal expression of the HER-2/neu oncogene, a tyrosine kinase-type transmembrane growth factor receptor localized to chromosome 17q, has been associated with poor prognosis and the prediction of therapy response in invasive breast cancer. The comparative incidence and significance of HER-2/neu gene amplification for lobular and ductal breast cancer have not been previously characterized.

DESIGN

Formalin-fixed, paraffin-embedded primary breast cancer tissue sections from 71 women diagnosed with invasive lobular carcinoma were tested for HER-2/neu gene amplification by fluorescence in situ hybridization (FISH) method using the Ventana unique sequence probe (Ventana Medical Systems, Tucson, AZ). A series of 106 cases of invasive ductal carcinoma was similarly processed and tested. Lymph node status was available for 155 (88%) of the 177 cases and 82 (46%) were lymph node-negative (LN-) and 73 (41%) were lymph node-positive (LN+). Patients were treated for a mean of 65 months (range 1-169 months).

RESULTS

9 of 71 (13%) cases of lobular cancer featured HER-2/neu gene amplification, whereas 51 (48%) of 106 cases of ductal cancer showed amplification (P < 0.0001). On univariate analysis of combined lobular and ductal cases, HER-2/neu gene amplification detected by FISH predicted disease-related death (P < 0.0001). HER-2/neu gene amplification also predicted disease-related death in lobular cases alone (P = 0.003), LN+ lobular cases separately (P = 0.019), and LN- and LN+ ductal cases separately and alone (P < 0.0001). Multivariate analysis of the lobular group alone revealed that LN+ status (P = 0.015) and stage (P = 0.01) were independent predictors of disease-related death, and HER-2/neu gene amplification reached near significance (P = 0.086). In the ductal carcinoma group alone, HER-2/neu gene amplification (P = 0.03), lymph node status (P = 0.0001), tumor stage (P = 0.0001), and tumor grade (P = 0.044) were independent predictors of overall disease survival.

CONCLUSIONS

HER-2/neu gene amplification detected by FISH was identified at a significantly lower rate in lobular compared with ductal breast cancer. HER-2/neu gene amplification when present in lobular breast cancer is a significant adverse prognostic factor.

Her-2/neu and breast cancer

Breast cancer is the most common malignancy in women in the United States in the year 2000. The proto-oncogene Her-2/neu (c-erb-B2) has become an increasingly important prognostic and predictive factor in breast cancer. Overexpression/amplification of the Her-2/neu has been associated with a worse outcome in patients with breast cancer. Herceptin, a "humanized" murine monoclonal antibody directed against the extracellular domain of the Her-2/neu protein, is being used to treat breast cancer that overexpresses Her-2/neu. The status of Her-2/neu in the tumor has become a critical factor in the management strategy of a breast cancer patient. The objective of this article is to provide a comprehensive review of all aspects of Her-2/neu in breast cancer, including biology, prognostic and predictive value, targeted Herceptin therapy, and the laboratory testing of Her-2/neu.

Biomarkers in disease and health

Biomarkers have considerable potential in aiding the understanding of the relationship between diet and disease or health. However, to assess the role, relevance and importance of biomarkers on a case by case basis it is essential to understand and prioritise the principal diet and health issues. In the majority of cases, dietary compounds are only weakly biologically active in the short term, have multiple targets and can be both beneficial and deleterious. This poses particular problems in determining the net effect of types of foods on health. In principle, a biomarker should be able to contribute to this debate by allowing the measurement of exposure and by acting as an indicator either of a deleterious or of an enhanced health effect prior to the final outcome. In this review, the examples chosen - cancer (stomach, colon/rectal, breast); coronary heart disease and osteoporosis - reflect three major diet-related disease issues. In each case the onset of the disease has a genetic determinant which may be exacerbated or delayed by diet. Perhaps the most important factor is that in each case the disease, once manifest, is difficult to influence in a positive way by diet alone. This then suggests that the emphasis for biomarker studies should focus on predictive biomarkers which can be used to help in the development of dietary strategies which will minimise the risk and be of greater benefit.

Transcriptional complementarity in breast cancer: application to detection of circulating tumor cells

BACKGROUND

We used a combination of genetic subtraction, silicon DNA microarray analysis, and quantitative PCR to identify tissue- and tumor-specific genes as diagnostic targets for breast cancer.

METHODS AND RESULTS

From a large number of candidate antigens, several specific subsets of genes were identified that showed concordant and complementary expression profiles. Whereas transcriptional profiling of mammaglobin resulted in the detection of 70% of tumors in a panel of 46 primary and metastatic breast cancers, the inclusion of three additional markers resulted in detection of all 46 specimens. Immunomagnetic epithelial cell enrichment of circulating tumor cells from the peripheral blood of patients with metastatic breast cancer, coupled with RT-PCR-based amplification of breast tumor-specific transcripts, resulted in the detection of anchorage-independent tumor cells in the majority of patients with breast cancer with known metastatic disease.

CONCLUSION

Complementation of mammaglobin with three additional genes in RT-PCR increases the detection of breast cancers in tissue and circulating tumor cells.

Effect of Ribonuclease A and Deoxyribonuclease I on Immunostaining of Ki-67 in Cultured Melanoma Cells

Immunostaining of the cell cycle-associated Ki-67 antigen was studied, using the Ki-67-specific MIB-1 monoclonal antibody on slides prepared by cytocentrifugation of cultured A375 melanoma cells. Immunomorphological analysis of the Ki-67 immunostaining pattern of both nuclear and nucleolar locations was carried out following pre-treatment of the slides including ribonuclease and deoxyribonuclease pre-digestion of the cells. Immunostaining of nucleolar Ki-67 was reduced by ribonuclease pre-digestion, but was not altered by deoxyribonuclease pre-treatment. Ribonuclease did not reduce the staining intensity of Ki-67 in the nuclear matrix, but the intensity decreased after deoxyribonuclease pre-digestion. We suggest that the Ki-67 molecule may play an important role in ensuring contact between nuclear DNA and nucleolar RNA during transcriptional processes in cell proliferation.

Microsomal epoxide hydrolase expression as a predictor of tamoxifen response in primary breast cancer: a retrospective exploratory study with long-term follow-up

PURPOSE

It has been suggested that estrogen receptor-independent high-affinity binding sites for antiestrogens could limit their local bioavailability and response. Microsomal epoxide hydrolase (mEH) was recently shown to be a component of the antiestrogen binding site complex. We investigated whether mEH expression in primary breast tumors is related to disease outcome and to the efficacy of tamoxifen treatment.

PATIENTS AND METHODS

Expression of mEH was semiquantitatively assessed by immunohistochemistry in sections prepared from archival paraffin blocks of primary breast cancers from 179 patients with a mean follow-up time of 81 months.

RESULTS

Expression of mEH was correlated with poor disease outcome in all patients (P: < .01; n = 179) and in patients receiving tamoxifen (P: < .01; n = 78), but not in patients not treated with tamoxifen. Moreover, mEH was an independent prognostic factor by Cox regression analysis.

CONCLUSION

The results of this first exploratory study suggest that mEH expression in primary breast cancer could be of predictive value for response to tamoxifen treatment and/or may be a novel independent prognostic factor for survival. The results are in agreement with the model that mEH participates in an estrogen receptor-independent tamoxifen- binding complex.

Expression of oncogenic epidermal growth factor receptor family kinases induces paclitaxel resistance and alters beta-tubulin isotype expression

Oncogenic transformation confers resistance to chemotherapy through a variety of mechanisms, including suppression of apoptosis, increased drug metabolism, and modification of target proteins. Oncogenic epidermal growth factor receptor family members, including EGFRvIII and HER2, are expressed in a broad spectrum of human malignancies. Cell lines transfected with EGFRvIII and HER2 are more resistant to paclitaxel-mediated cytotoxicity, and tubulin polymerization induced by paclitaxel is suppressed compared with cells expressing wild type epidermal growth factor receptor. Because differential expression of beta-tubulin isotypes has been proposed to modulate paclitaxel resistance, we analyzed beta-tubulin isotypes expressed in cell lines transfected with different oncogenes. EGFRvIII- and HER2-expressing cells demonstrated equivalent total beta-tubulin protein compared with cells transfected with wild type receptor or untransfected controls. EGFRvIII-expressing cells demonstrated increases in class IVa (2.5-fold) and IVb (3.1-fold) mRNA, and HER2-expressing cells showed increases in class IVa (2. 95-fold) mRNA. Expression of oncogenic Ha-Ras did not change class IV RNA levels significantly. Inhibition of EGFRvIII kinase activity using a mutant allele with an inactivating mutation in the kinase domain decreased expression of class IVa by 50% and partially reversed resistance to paclitaxel. Expression of oncogenic epidermal growth factor receptor family members is associated with modulation of both beta-tubulin isotype expression and paclitaxel resistance in cells transformed by expression of the receptor. This effect on tubulin expression may modulate drug resistance in human malignancies that express these oncogenes.

Normalizing complementary DNA by quantitative reverse transcriptase-polymerase chain reaction of beta2-microglobulin: molecular monitoring of minimal residual disease in acute promyelocytic leukemia

Reverse transcription (RT)-polymerase chain reaction (PCR) raises unique methodological matters that may hamper the reliability of the procedure, especially when results should direct therapeutic decisions. One of these matters is represented by the RT step. The present study shows that differences in complementary DNA (cDNA) preparations purposely containing increasing amounts of retrotranscribed RNA were not disclosed by nonquantitative RT-PCR by two different housekeeping genes, leading to fictitious results when the expression of a given gene was quantitatively assessed. To overcome this problem, the following are proposed: 1) to evaluate the efficiency of RT step through the quantification, by competitive RT-PCR, of the expression levels of the housekeeping gene beta2-microglobulin (beta2M); 2) to normalize each cDNA preparation to be comprised within 1 standard deviation of the mean value of beta2M absolute level (3.14 +/- 1.14 attomoles/microg RNA) found by analyzing 33 cell lines of hematopoietic origin. To validate this strategy in a clinical setting, serial cDNA samples from patients were checked by conventional and quantitative RT-PCR for beta2M. Again, only a quantitative evaluation of beta2M levels was allowed to unveil significant differences, otherwise undetected, in the efficiency of RT reactions among these cDNA samples. Normalization of samples to obtain cDNA preparations containing comparable beta2M levels, eventually led to an increased sensitivity in the detection of PML-RARalpha fusion transcripts. This approach seems of great value for the monitoring of minimal residual disease in serial patient samples when a tumor-specific marker is available.

A simple index using video image analysis to predict disease outcome in primary breast cancer

Image analysis was used to investigate the prognostic significance of immunostaining for oestrogen receptor (ER), p53 tumour-suppressor protein and tumour cell proliferation (MIB-1) in a random cohort of 200 primary breast cancer patients with between 4 and 7 years of clinical follow-up. Image measurements of the percentage of immunopositive cancer cell nuclei (% positive nuclear area) were recorded for the above tumour features for each patient. Assessment of relative risk using Cox's univariate analysis indicated that tumour size, number of cancer-involved nodes, MIB-1 and ER % positive nuclear area were significantly associated with breast cancer disease outcome, i.e., relapse-free survival and overall survival. In multivariate analysis, tumour size, number of involved nodes, ER and MIB-1 % positive nuclear area were retained as independent predictors of prognosis, depending on the image measurement cut-point used. A prognostic model, which can be used without reference to nodal involvement, was constructed for tumour size, ER cut-point of 30% positive nuclear area and MIB-1 cut-point of 10% positive nuclear area. Kaplan-Meier analysis of this image-based prognostic index identified 4 risk groups with predicted 5-year overall survival rates of 93%, 83%, 76.7% and 61.5%. We conclude that image measurements of ER and proliferative rate can be combined with tumour size to construct a prognostic index which reliably predicts disease outcome in primary breast cancer without knowledge of the nodal status of the patient.

Expression of interleukin 6 (IL-6) correlates with oestrogen receptor in human breast carcinoma

Multifunctional cytokines play important and only partially defined roles in mammary tumour development and progression. Normal human mammary epithelial cells constitutively produce interleukin 6 (IL-6), IL-8 and a non-secreted form of tumour necrosis factor. Transformation of mammary epithelial cells by different oncogenes is frequently associated with alterations of cytokine/growth factor production and responsiveness. In the present study we analysed the expression of IL-6 in 149 cases of invasive breast carcinoma and the data have been correlated with clinico-pathological variables including tumour size, histological grade, nodal status, and oestrogen and progesterone receptors, Ki67 and p53, protein expression. Though the majority of breast carcinomas expressed at least low levels of immunoreactive IL-6, we found that expression of this cytokine was inversely associated with histological tumour grade (P = 0.0017), but not with tumour size and nodal status. Ki67 positivity was inversely correlated with IL-6 expression (P = 0.027). Among biological parameters analysed, a direct association was found between the percentage of IL-6-positive cells and that of oestrogen (P = 0.00005) and progesterone (P = 0.025) receptor-positive cells. No correlation was observed between IL-6 and p53 protein expression. These data indicate that down-regulation of IL-6 is associated with highly malignant mammary carcinomas. It will be of interest to evaluate whether alterations of cytokines that are constitutively produced by mammary cells are also associated with high-grade tumours.

Prognostic value of uPA and p53 accumulation measured by quantitative biochemical assays in 1245 primary breast cancer patients: a multicentre study

The purpose of this retrospective multicentre study was to assess the prognostic value of urokinase plasminogen activator (uPA) and p53 levels in a large series of primary breast cancer, using an automatic quantitative luminometric method. Samples of 1245 operable breast tumours were collected from seven French institutions and patients were followed for a median of 75 months. The median uPA and p53 levels assayed in cytosols by means of the immunoluminometric technique (LIA) were 0.31 and 0.20 ng mg(-1) of protein respectively. In univariate analysis, high levels of uPA and p53 were associated with shorter disease-specific survival, disease-free interval, and distant recurrence-free interval. The 5-year survival rates were 95.5% among patients with uPA values below the 20th percentile, and 77.5% in those with values above the 80th percentile. The 5-year survival rates were 91.0% in patients with p53 values below the 20th percentile, and 77.6% in those with values above the 80th percentile. In multivariate analysis, the risk of disease-related death increased with uPA levels after adjustment for tumour size, histological grade, lymph node involvement, and estrogen receptor status. A high level of uPA was also related to a shorter disease-free interval and distant recurrence-free interval. In node-negative patients, a high level of uPA remained strongly related to the three outcomes. When adjusted for other prognostic factors, p53 was no longer significantly related to the outcomes. Given its rapidity and simple application to routinely prepared cytosols, this LIA may be useful for evaluating the prognostic impact of uPA in primary breast cancer, particularly in node-negative patients. According to our results, the prognostic value of p53 accumulation is limited when uPA is included in multivariate analysis.

The HER-2/neu oncogene: prognostic factor, predictive factor and target for therapy

The HER-2/neu oncogene encodes a transmembrane tyrosine kinase receptor with extensive homology to the epidermal growth factor receptor. HER-2/neu has been widely studied in breast cancer. The potential value of HER-2/neu status for the prediction of disease outcome and response to therapy in breast cancer is presented in the light of a series of recently published studies showing a range of impact on the outcome of patients treated with hormonal, cytotoxic and radiation therapies. This review includes the application of serum-based HER-2/neu testing and the use of antibody-based therapies directed against the HER-2/neu protein and their potential to become a new modality for breast cancer treatment.

Low tumour cell proliferation at the invasive margin is associated with a poor prognosis in Dukes' stage B colorectal cancers

The conflicting results about the prognostic impact of tumour cell proliferation in colorectal cancer might be explained by the heterogeneity observed within these tumours. We have investigated whether a systematic spatial heterogeneity exists between different compartments, and whether the presence of such a systematic heterogeneity has any impact on survival. Fifty-six Dukes' stage B colorectal cancers were carefully morphometrically quantified with respect to the immunohistochemical expression of the proliferative marker Ki-67 at both the luminal border and the invasive margin. The proliferative activity was significantly higher at the luminal border compared with the invasive margin (P<0.001), although the two compartments were also significantly correlated with each other. Tumours with low proliferation at the invasive margin had a significantly poorer prognosis both in univariate (P = 0.014) and in multivariate survival analyses (P = 0.042). We conclude that Dukes' B colorectal cancers exhibit a systematic spatial heterogeneity with respect to proliferation, and tumours with low proliferation at the invasive margin had a poor prognosis. The present data independently confirm recent results from the authors, and provide new insights into the understanding of tumour cell proliferation in colorectal cancer.

Integration of estrogen and progesterone receptors with pathological and molecular prognostic factors in breast cancer patients

In this study we have examined biopsies from women with localized primary breast cancer to investigate the prognostic performance of estrogen receptors (ER) and progesterone receptors (PR) for estimating the metastatic probability of the patients, and to explore whether discrimination gets better by combining clinicopathological and other molecular parameters into a score. This prospective study involved 205 patients with a median follow-up of 5 y. Among the evaluated clinicopathological data were: patient's age; tumor size; axillary lymph node involvement; and tumor grade. The most representative tumor samples were derived to a single laboratory for immunohistochemical evaluation of the following molecular markers: ER, PR, proliferating cell nuclear antigen (PCNA), p53 protein product, erbB-2 (HER-2/neu) oncoprotein, and P170 glycoprotein (mdrl gen product). Distant metastases (study endpoint) appeared in 19.5% (40/205) of the patients, most of these patients presented a mixture of poor, regular and good prognostic factors. Disease-free survival analysis procedures (Kaplan-Meier method) identified tumor size, axillary lymph node involvement, tumor grade, receptor status, PCNA, p53, erbB-2 and P170 as useful prognostic factors. Proportional hazard regression analysis (Cox) identified in order of importance erbB-2, tumor size, receptors status, tumor grade and PCNA as useful prognostic factors. To facilitate the evaluation of the prognostic factors, a practical and simple score system was derived. A high pathological score identified 65% of the patients that developed distant metastases, while a high molecular score was obtained in 57% of patients with metastatic disease. There was a significant improvement in the diagnosis of probability of being with distant metastases when the pathological score was combined with the molecular score, 82% of the patients with distant metastases showed an elevated combined score. Validation of this scoring system will need further larger studies (validation set as opposed to the training set used in the present study). Due to the complexity of events in cancer, the evaluation of a combination of prognostic factors should be of value to clinicians to make a more objective estimate of the prognosis of individual breast cancer patients.

The HER-2/neu oncogene in breast cancer: prognostic factor, predictive factor, and target for therapy

The HER-2/neu oncogene encodes a transmembrane tyrosine kinase receptor with extensive homology to the epidermal growth factor receptor. HER-2/neu has been widely studied in breast cancer. In this review, the association of HER-2/neu gene and protein abnormalities studied by Southern and slot blotting, immunohistochemistry, enzyme immunoassays, and fluorescence in situ hybridization with prognosis in breast cancer is studied in depth by review of a series of 47 published studies encompassing more than 15,000 patients. The relative advantages of gene amplification assays and frozen/fresh tissue immunohistochemistry over paraffin section immunohistochemistry are discussed. The significance of HER-2/neu overexpression in ductal carcinoma in situ and the HER-2/neu status in uncommon female breast conditions and male breast cancer are also considered. The potential value of HER-2/neu status for the prediction of response to therapy in breast cancer is presented in the light of a series of recently published studies showing a range of impact on the outcome of patients treated with hormonal, cytotoxic, and radiation therapies. The evidence that HER-2/neu gene and protein abnormalities in breast cancer predict resistance to tamoxifen therapy and relative sensitivity to chemotherapy regimens including adriamycin is presented. The review will also evaluate the status of serum-based testing for circulating the HER-2/neu receptor protein and its ability to predict disease outcome and therapy response. In the final section, the review will briefly present preliminary data concerning the use of antibody-based therapies directed against the HER-2/neu protein and their potential to become a new modality for breast cancer treatment. The recently presented phase III clinical trial evidence that systemic administration of anti-HER2 antibodies (Herceptin), alone and in combination with cytotoxic chemotherapy in patients with HER-2/neu overexpressing primary tumors, can increase the time to recurrence and overall response rates in metastatic breast cancer is reviewed.

Flow cytometry in breast cancer: prognostic and surgical indications of the sparing of axillary lymph node dissection

The lymph node status is still regarded as the most important prognostic factor in breast cancer. However, the utility of axillary lymph node dissection in clinically node-negative patients with breast cancer as a therapeutic approach rather than a pathologic staging procedure has been recently discussed. DNA index (DI) and S-phase fraction (SPF), evaluated by flow cytometric analysis, are two prognostic factors used especially in the assessment of the adjuvant therapy in stage N0 tumors. By studying a large number of cases, the authors aimed to assess the potential role of flow cytometry in predicting lymph node status. Two hundred eleven patients with breast cancer were included. Each tumor specimen was freshly analyzed by flow cytometry to assess DI and SPF. The authors also evaluated TNM status of patients, estrogen- and progesterone-receptor (ER and Pgr) status, and histologic grades. A group of patients with negative axillary lymph nodes was identified by means of association of tumor size of 2 cm or less, DI of 1, and SPF less than 7%. The ER and PgR status as well as histologic grade were significantly more favorable in this group of patients. These findings indicate that association of DI, SPF value, and tumor size may be predictive of axillary lymph node status in breast cancer.

Expression of c-met is a strong independent prognostic factor in breast carcinoma

BACKGROUND

The c-met protooncogene encodes the met protein, the receptor for scatter factor/hepatocyte growth factor, a growth factor that modulates the motility and stable interaction of the epithelial cells. This study assesses the expression of met receptor in breast carcinoma and its prognostic value with respect to survival.

METHODS

Immunofluorescence was used to evaluate 91 archival breast carcinoma specimens using a polyclonal antibody to the cytoplasmic domain of the receptor. Cases were scored by two pathologists on a percentage basis and then converted to binary scores (positive or negative) on the basis of a bimodal distribution.

RESULTS

Strong expression of met was found in 20 invasive ductal breast tumor specimens (22%). The 5-year survival of patients whose tumors showed decreased met expression was 89%, in contrast to a 52% 5-year survival rate in patients whose tumors expressed met (P = 0.008). This trend also was observed in patients without lymph node metastases at presentation, in whom met negative patients had a 95% 5-year survival compared with only 62% for met positive patients (P = 0.006) Multivariate analysis using the Cox proportional hazards model showed met expression to be an independent predictor of survival, with a predictive value nearly equivalent to that associated with lymph node status.

CONCLUSIONS

The authors conclude that expression of met in patients with invasive ductal carcinoma of the breast is a strong, independent predictor of decreased survival and may be a useful prognostic marker with which to identify a subset of patients with more aggressive disease.

Prostate-specific antigen induction by a steroid hormone in T47D cells growing in SCID mice

Previous studies revealed that prostate-specific antigen (PSA) is present in > 30% of human breast tumor cytosols. Survival analysis showed that patients with PSA-producing tumors have a reduced risk for relapse, suggesting PSA to be an independent favorable prognostic marker for a large subset of breast cancer patients. The present investigation established an in vivo model for the induction of PSA in human breast cancer tumors growing as xenografts in severe combined immunodeficient (SCID) mice. The human mammary cancer cell-line T47D was grown i.m. in female mice. When the tumor and leg diameter reached 10 mm, the mice were stimulated daily with norgestrel for either 5 or 7 days to produce PSA, and sacrificed on day 8. The prostate cancer cell-line LNCaP was grown in male mice and functioned as a positive control for PSA production. After T47D and LNCaP mice were sacrificed, a highly sensitive immunofluorometric assay was used to analyze the PSA concentration in the tumor, muscle, liver, and kidney cytosols. Norgestrel-stimulated T47D mice showed significantly more PSA in the tumors compared to tumors of the control mice. However, PSA levels in tumors of the stimulated mice were significantly lower than those in the LNCaP xenografts. No PSA levels above background were present in the blood and normal tissue of the norgestrel-stimulated or control T47D xenografts. This mouse model will be a valuable tool for investigating and screening new therapies for a subgroup of breast cancer patients who have significant PSA concentrations in their tumors.

Assessment of c-erbB2 and vascular endothelial growth factor mRNA expression in fine-needle aspirates from early breast carcinomas: pre-operative determination of malignant potential

AIMS

Although axillary lymph nodes status, tumour size, hormonal-receptor status and histological grade at diagnosis are frequently used to orient the treatment of breast cancer patients, some tumours recur in patients with early stage disease. Pre-operative assessment of individual tumour characteristics, based on oncogenes and growth factors related to tumour growth, invasion or metastasis, may guide the treatment for patients with breast carcinomas.

METHODS

We examine here the prognostic significance of cyclin D1, urokinase type plasminogen activator, vascular endothelial growth factor (VEGF), platelet-derived growth factor, and c-erbB2 expression in pre-operatively obtained fine-needle aspirates from breast carcinomas less than or equal to 3 cm in size. Correlation between mRNA expression of these factors and clinicopathological characteristics was analysed.

RESULTS

The level of c-erbB2 mRNA expression was significantly higher in tumours with lymph node metastases than in those without lymph node metastases. VEGF mRNA expression positively correlated with the degree of angiogenesis as quantitated by immunohistological staining with a CD31 monoclonal antibody.

CONCLUSIONS

Analysis of c-erbB2 and VEGF mRNA expression in fine-needle aspirates may be useful in assessing the malignant potential of individual breast carcinomas, leading to a pre-operative discrimination of a high-risk group.

Establishment and characterization of a new mammary adenocarcinoma cell line derived from MMTV neu transgenic mice

A new murine cell line, named MG1361, was established from mammary adenocarcinomas arising in a MMTV-neu transgenic mouse lineage where breast tumors develop in 100% of females, due to the overexpression of the activated rat neu oncogene in the mammary gland. The MG1361 cell line shows an epithelial-like morphology, has a poor plating efficiency, low clonogenic capacity, and a doubling time of 23.8 hours. Karyotype and flow cytometry analysis revealed a hypotetraploid number of chromosomes, whereas cell cycle analysis showed 31.2% of cells to be in the G1 phase, 21.4% in S and 47.4% in G2 + M. This cell line maintains a high level of neu expression in vitro. The MG1361 cell line was tumorigenic when inoculated in immunodeficient (nude) mice and the derived tumors showed the same histological features as the primary tumors from which they were isolated. MG1361 cells were positive for specific ER and PgR binding which was competed by tamoxifen, making this cell line useful for the evaluation of endocrine therapy. Moreover, they were sensitive to etoposide treatment, suggesting that they could be a model for the study of chemotherapy-induced apoptosis. As the tumors arising in MMTV-neu transgenic mice have many features in common with human mammary adenocarcinomas (Sacco et al., Gene Therapy 1995; 2: 493-497), this cell line can be utilized to perform basic studies on the role of the neu oncogene in the maintenance of the transformed phenotype, and to test novel protocols of therapeutic strategies.

Preoperative assessment of tumor angiogenesis by vascular endothelial growth factor mRNA expression in homogenate samples of breast carcinoma: fine-needle aspirates vs. resection samples

BACKGROUND AND OBJECTIVES

Tumor angiogenesis is receiving increased attention as a prognostic factor and also as a possible target for new anticancer agents. We investigated whether extent of vascular endothelial growth factor (VEGF) mRNA expression correlated with degree of neovascularization, and whether this expression in fine-needle aspirates could be a marker for assessing angiogenic potential of breast tumors.

METHODS

VEGF mRNA expression was semiquantitated by reverse transcriptase-polymerase chain reaction (RT-PCR) followed by Southern blotting. Tumor neovascularization was assessed by immunohistochemical staining with anti-CD31 (PECAM) antibody.

RESULTS

There was a positive correlation between degree of neovascularization and semiquantitated VEGF mRNA expression in invasive ductal carcinomas (r2 = 0.346, n = 48, P < 0.05). Extent of VEGF mRNA expression in fine-needle aspirates was closely correlated with that in resected invasive ductal carcinomas equal to or less than 3 cm in size (r2 = 0.874, n = 14, P < 0.05).

CONCLUSION

These data suggest that semiquantitation of VEGF mRNA expression in fine-needle aspirates is useful for assessing angiogenic potential of invasive ductal carcinomas.

A simple index to predict prognosis independent of axillary node information in breast cancer

BACKGROUND

Since the course of breast cancer is often unpredictable, we wished to develop a model using characteristics of the primary tumour alone to predict prognosis.

METHODS

Several tumour features were determined, and after a median follow-up duration of 65 months, multivariate analysis identified tumour size and grade, oestrogen receptor concentration, axillary lymph node metastasis and tumour cell proliferation fraction (MIB-1 count) as being independently associated with increases in risk for both relapse and death from breast cancer. A prognostic model was constructed using tumour size and grade, oestrogen receptor concentration and MIB-1 count only. A score of 1 for each was given to tumour size > 20 mm, tumour grade 2 or 3, oestrogen receptor concentration < 10 fmol/mg cytosol protein and MIB-1 count > 9%. Five groups established by assigning a combined score of 0, 1, 2, 3 or 4 for each patient were analysed for their associations with disease-free and overall survivals.

RESULTS

This preliminary model predicted 5-year survival rates of 97, 91, 85, 68 and 50% for the five groups. The model was further simplified by excluding tumour grade from the analysis. The revised model identified four risk groups with predicted 5-year survival rates of 91, 86, 66 and 52%. This model, the Adelaide prognostic index, was also able to identify four risk groups in both node-negative and node-positive patients.

CONCLUSIONS

The Adelaide prognostic index can be used to predict prognosis even in the absence of axillary lymph node information.

Establishment of breast cell cultures and lines from peoples of African origin

OBJECTIVES

The purpose of our study was to establish breast epithelial cell cultures and cell lines from peoples of African origin (blacks). It is presumed that the biology of breast cancer in women of African origin has unique aspects that can be explored using cultured breast epithelial cells.

STUDY DESIGN

Biopsy specimens were obtained from black women undergoing radical or modified mastectomies. Normal cell cultures were established using tissue from reduction mammaplasties or the milk of lactating mothers. The tissue specimens were lacerated, digested with collagenase solution, and plated on tissue culture plates. To extend the life of the epithelial cells in culture, they are transformed with SV40 virus.

RESULTS

We have maintained breast tumor cells in culture from a 27-year-old black woman for more than 1 month.

CONCLUSION

Despite the difficulty of establishing epithelial cell cultures, we have maintained breast tumor cells from blacks in culture for an extended period to allow characterization.

Proliferating cell nuclear antigen and heat shock protein 70 immunolocalization in invasive ductal breast cancer not otherwise specified

A series of 80 female patients undergoing surgery for primary breast ductal infiltrating carcinoma not otherwise specified (NOS) was immunohistochemically studied in order to verify any relationships between Proliferating Cell Nuclear Antigen (PCNA) immunostaining, Heat Shock Protein 70 (HSP70) immunoreactivity, and several clinicopathological predictors. Positive PCNA scores (> 20% of strongly immunopositive malignant nuclei) were observed in neoplastic cells' nuclei in 13 tumors (16.25%) and were intimately associated with axillary nodal involvement (p = 0.0131), relatively high tumor grades (p = 0.0016), increased tumor size (p = 0.0312), and low or negative levels of estrogen receptors (p = 0.0323). HSP70 positive immunoexpression in malignant cells' cytoplasm (percentage of HSP70 immunoreactive cells > 10%) was detected in 33 samples (41.25%). It correlated significantly with presence of axillary lymph nodal metastases (p = 0.0033) and rather poor tumor differentiation (p = 0.0014), whereas an association of borderline statistical significance emerged between HSP70 immunoreactivity and high progesterone receptor status (p = 0.0637). PCNA positive immunostaining demonstrates the tumors' proliferative fraction and might be used as an indicator of increased malignant potential in breast cancer since it was associated with four adverse prognosticators. HSP70 immunodetection is a probable marker of the biological stress experienced by breast cancer cells, since it was related to relatively high tumor grades. Since both proteins may potentially predict disease outcome, their prognostic significance must be validated by direct relation to survival. A multivariate statistical analysis including the variables with which both proteins were associated will reveal any possible independent prognostic value of PCNA and HSP70 immunostaining in local, ductal invasive breast cancer NOS.

Differential distribution of ErbB-2 and pS2 proteins in ductal carcinoma in situ of the breast

We examined the expression of ErbB-2 and pS2 proteins in 59 ductal carcinoma in situ (DCIS) of the breast, either pure DCIS or DCIS associated with invasive carcinoma, using immunohistochemical staining of paraffin-embedded sections. Positive staining for ErbB-2 and pS2 proteins was noted in 32% (19/59) and 46% (27/59) of DCIS, respectively. An inverse relationship between ErbB-2 and pS2 status in DCIS was observed (p < 0.01). From the viewpoint of histological subtype, the prevalence of ErbB-2 protein expression was significantly higher in the comedo subtype than the cribriform-micropapillary subtype. The prevalence of immunoreactivity for ErbB-2 in solid subtype was intermediate between those of the other two groups. In contrast, the prevalence of pS2 expression was significantly lower in the comedo subtype than in the cribriform-micropapillary subtype. Again, the prevalence of pS2 protein expression in the solid subtype was intermediate between those of the other two subtypes. Our results suggest that DCIS is biologically heterogeneous with regard to such marker substances. This has possible implications for management of these lesions.

Proliferation markers

Types of growth include embryonic, fetal, neonatal, juvenile and mature. Until full differentiation is achieved, cells grow through proliferation from progenitor cells. At maturity, the cellular genome is fixed with committed patterns of cell cycle duration and adaptation, ranging from static to renewing type 3. The static cell type cannot proliferate and adapts through hypertrophy. The renewing type continuously proliferates even without stimulus. In all cell types the processes of differentiation and proliferation are mutually exclusive. Cellular kinetics involve (a) the duration of the cell cycle, (b) the birth rate of cells, and (c) the growth rate fractions. The duration of the cell cycle is 2-4 days. All growth factors (GF) exert their influence during G1 phase. Release a GF by one cell type can influence the proliferation of another (= paracrine stimulation). At the end of G1 is the point of highest sensitivity to toxicity. Tumor suppressor genes act here through tyrosine phosphorylation. During S, the cell replicates its chromosomes. During G2 the immune surveillance and DNA damage repair mechanisms operate. Injured cells stay here longer enabling repair of their damaged DNA. Cell division involves both nuclear (mitosis) and cytoplasmic (cytokinesis) phases giving rise to 2 new cells. The cell cycle has 2 checkpoints. The first involves the G1-S transition and the second the G2-M transition. The types of cell cycle inhibition include (a) cycle- and phase-specific inhibition; (b) cycle-and nonphase-specific inhibition; (c) noncycle-and nonphase-specific inhibition, and finally (d) noncycle, nonphase-, and nonorgan-specific inhibition. Proliferation is a circadian process and it is stimulated by a variety of stimuli which include (1) interference with hormonal feedback pathways; (2) inhibition of the tissue trophic activity; (3) sustained presence of antigenic substances; (4) tissue ischemia; (5) changes of conditions luminally or on surfaces of tissues; (6) sustained cytotoxicity; (7) cell death; and (8) surgical resection. Proliferation can be arrested through senescence, apoptosis, injury or even during the development of immune cells. In the past, tissue/cell kinetics have been studied by tritiated thymidine histoautoradiography. Recently, monoclonal antibodies to proliferation-associated antigens, have been successfully employed. These antigens are cycle-associated proteins and include (1) PCNA; (2) p53; (3) Ki67; (4) AGNOR; (5) Statin; and (6) BrdU. Practical examples are given comparing PCNA and BrdU markers from 3 tissues, i.e. liver, glandular stomach, and uterus, across 2 or 3 strains of rats. Mean values of labeling indices are cited. Within the PCNA marker, 2 different clones are compared from the glandular stomach of SD rats of 2 different ages. Gender and across species comparisons are also made. All these comparisons denote that in every study where markers are used (a) there is a need for a concurrent study control group of the same age; (b) there is a need for in-house control data for this particular organ by species, strain, gender and age; (c) there is ancillary assessment of the trophic status of the target tissue; (d) there is a need for at least 2 different time points during assessment; (e) there is a need for such proliferation data prior to commencing the 2 year rodent bioassay; and (f) that PCNA is the most reliable and versatile of all markers used, capable of rendering good results even from archival specimens.