Prognostic value of proliferation in invasive breast cancer: a review

Prognostic significance of tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor expression in patients with breast cancer

TNF-related apoptosis-inducing ligand (TRAIL) induces apoptosis upon binding to TRAIL receptors 1 and 2 (TRAIL-R1/DR4 and TRAIL-R2/DR5). TRAIL-R3 (DcR1) and TRAIL-R4 (DcR2) have no or only a truncated cytoplasmic death domain. Consequently, they cannot induce apoptosis and instead have been proposed to inhibit apoptosis induction by TRAIL. Agonists for the apoptosis-inducing TRAIL-R1 and TRAIL-R2 are currently tested in clinical trials. To determine the expression pattern of all surface-bound TRAIL receptors and their prognostic clinical value, we investigated tumour samples of 311 patients with breast cancer by immunohistochemistry. TRAIL receptor expression profiles were correlated with clinico-pathological data, disease-free survival and overall survival. TRAIL-R1 was more strongly expressed in better differentiated tumours, and correlated positively with surrogate markers of a better prognosis (hormone receptor status, Bcl-2, negative nodal status), but negatively with the expression of Her2/neu and the proliferation marker Ki67. In contrast, TRAIL-R2 and TRAIL-R4 expression correlated with higher tumour grades, higher Ki67 index, higher Her2/neu expression and a positive nodal status at the time of diagnosis, but with lower expression of Bcl-2. Thus, the TRAIL receptor expression pattern was predictive of nodal status. Patients with grade 1 and 2 tumours, who had TRAIL-R2 but no TRAIL-R1, showed a positive lymph node status in 47% of the cases. Vice versa, only 19% had a positive nodal status with high TRAIL-R1 but low TRAIL-R2. Most strikingly, TRAIL-R4 and -R2 expression negatively correlated with overall survival of breast cancer patients. Although TRAIL-R2 correlated with more aggressive tumour behaviour, mammary carcinoma could be sensitised to TRAIL-R2-induced apoptosis, suggesting that TRAIL-R2 might therefore be used to therapeutically target such tumours. Hence, determination of the TRAIL receptor expression profile may aid in defining which breast cancer patients have a higher risk of lymph node metastasis and worse overall survival and on the other hand will help to guide TRAIL-based tumour therapy.

A shift from nuclear to cytoplasmic breast cancer metastasis suppressor 1 expression is associated with highly proliferative estrogen receptor-negative breast cancers

BACKGROUND/AIMS

To determine breast cancer metastasis suppressor 1 (BRMS1) expression in breast cancers and the efficacy of BRMS1 as a prognostic indicator, BRMS1 expression was assessed in two sets of breast cancer tissues.

METHODS

Epithelial cells from 36 frozen samples of breast cancers and corresponding normal breast were collected by laser capture microdissection and assessed for BRMS1 by quantitative RT-PCR and immunohistochemistry. BRMS1 was also evaluated by immunohistochemistry in a tissue microarray of 209 breast cancers and correlated with indicators of prognosis [estrogen receptor (ER), progesterone receptor (PR), ErbB2, p53, p27(Kip1), Bcl2 and Ki-67].

RESULTS

BRMS1 mRNA and protein were higher in 94 and 81%, respectively, of breast cancers than in corresponding normal epithelium. BRMS1 localization was predominantly nuclear, but 60-70% of cancers also exhibited cytoplasmic immunostaining. Breast cancers with lower nuclear than cytoplasmic BRMS1 (nuclear score - cytoplasmic score < or =0; 11% of cancers) had lower ER, lower PR and higher Ki-67 expression. There was also a trend toward poorer overall survival in this group of cancers, but this was only of borderline significance (p = 0.073). In Cox proportional hazards models, loss of nuclear BRMS1 was not a significant predictor of overall survival.

CONCLUSIONS

Loss of nuclear BRMS1 was associated with ER-negative cancers and a high rate of proliferation, but was not an independent indicator of prognosis.

Alterations of the cell cycle regulators cyclin D1, cyclin A, p27, p21, p16, and pRb in apocrine metaplasia of the breast

G1/S transition defects have been a proposed requirement for tumor development. Apocrine metaplasia (APM) in the breast has been held as a sign of benignity. Yet, a number of studies have reported the presence of molecular abnormalities in some forms of APM suggesting a possible oncogenic potential for some of these lesions. We currently investigate the role of some of the cell cycle proteins, previously reported to be de-regulated in breast cancer, in an attempt to assess their significance in APM. Using immunohistochemistry, the expression of cyclin D1, cyclin A, p27, p21, p16, pRb and Ki-67 was examined in 93 cases of APM. The cases were divided into nonpapillary (NAPM) (30 cases) and papillary metaplasia (PAPM) (63 cases). PAPM was further subdivided into simple papillary (SPAPM) (29 cases), complex papillary (28 cases) and highly complex papillary (six cases). For statistical analysis, the last two groups were merged together (CPAPM). The results showed that increased histological complexity was associated with significant increase of proliferative capacity and alterations of the cell cycle control. The median Ki-67 index was 1.5% in SPAPM and 4.8% in the CPAPM. Also, alterations of the cell cycle regulators were significantly higher in the CPAPM than in the SPAPM. NAPM was generally similar to normal breast epithelium. Apocrine cells were negative for p16 while pRb was expressed in all cases. These findings suggest that in complex forms of APM, there is a considerable degree of cellular unrest. This may contribute to increased susceptibility to carcinogenesis.

Multigene classifiers, prognostic factors, and predictors of breast cancer clinical outcome

A series of multigene classifiers, prognostic and predictive tests have recently been introduced as potentially useful adjuncts for the management of recently diagnosed breast cancer patients. These tests have used both slide-based methods including immunohistochemistry and fluorescence in situ hybridization and nonmorphology driven molecular platforms including quantitative multiplex real time polymerase chain reaction and genomic microarray profiling. In this review, a series of partially and completely commercialized multigene assays are compared with the standard breast cancer clinico-pathologic variables and biomarkers and evaluated as to the level of their scientific validation, current clinical utility, regulatory approval status, and estimated cost-benefit. A comparison of the Oncotype Dx and MammaPrint assays indicates that the Oncotype Dx test has the advantages of an earlier commercial launch in the US, wide acceptance for payment by third party payors, the ease of use of formalin fixed paraffin embedded tissues, a recommendation as ready for use by the American Society of Clinical Oncology Breast Cancer Tumor Markers Update Committee, a continuous rather than dichotomous algorithm, inclusion of both estrogen receptor (ER) and human epidermal growth factor receptor 2 in the mRNA profile, an ability to serve as both a prognostic and predictive test for certain hormonal and chemotherapeutic agents, demonstrated cost-effectiveness in 1 published study, and a high accrual rate for the prospective validation clinical trial (Trial Assigning Individualized Options for Treatment Rx). The MammaPrint assay has the advantages of a 510(k) clearance by the US Food and Drug Administration, a larger gene number which may enhance further utility, and the potentially wider patient eligibility including lymph node-positive, ER-negative, and younger patients being accrued into the prospective trial (the Microarray in Node-negative Disease may Avoid ChemoTherapy). A number of other assays have specific predictive goals most often focused on the efficacy of tamoxifen in ER-positive patients such as the Two-gene Ratio test and the Cytochrome P450 CYP2D6 genotyping assay.

Membranous and cytoplasmic staining of Ki67 is associated with HER2 and ER status in invasive breast carcinoma

AIMS

Membranous and cytoplasmic Ki67 immunoreactivity has recently been observed in a number of histopathological entities, but frequency of occurrence and relationship to prognosis in more common cancers have not been described. The aim was to describe the pattern and frequency of membranous/cytoplasmic Ki67 in a cohort of invasive breast carcinomas, and their associations with grade, HER2 amplification and oestrogen receptor (ER) expression.

METHODS AND RESULTS

Three hundred and twenty-two cases of invasive ductal carcinoma were assessed for histological grade, Ki67 (MIB-1 clone) proliferation index and pattern of immunoreactivity, ER expression by immunohistochemistry, and HER2 amplification status by fluorescence in situ hybridization. Overall, 26/322 (8%) breast carcinomas showed membranous/cytoplasmic Ki67, and expression was significantly associated with grade 3, HER2-amplified and ER- tumours. Membranous/cytoplasmic Ki67 was not, however, an independent prognostic factor on multivariate analysis.

CONCLUSIONS

Membranous/cytoplasmic Ki67 identifies a group of breast carcinomas that may be important to consider separately in prognostic and predictive studies. The mechanism of subcellular Ki67 relocalization remains elusive and further studies are required to establish both the cause and effect of this unusual pattern of Ki67 immunoreactivity.

Prediction of paclitaxel sensitivity by CDK1 and CDK2 activity in human breast cancer cells

Introduction

Paclitaxel is used widely in the treatment of breast cancer. Not all tumors respond to this drug, however, and the characteristics that distinguish resistant tumors from sensitive tumors are not well defined. Activation of the spindle assembly checkpoint is required for paclitaxel-induced cell death. We hypothesized that cyclin-dependent kinase (CDK) 1 activity and CDK2 activity in cancer cells, which reflect the activation state of the spindle assembly checkpoint and the growth state, respectively, predict sensitivity to paclitaxel.

Methods

Cell viability assays and DNA and chromatin morphology analyses were performed in human breast cancer cell lines to evaluate sensitivity to paclitaxel and the cell cycle response to paclitaxel. We then examined the specific activities of CDK1 and CDK2 in these cell lines and in xenograft models of human breast cancer before and after paclitaxel treatment. Protein expression and kinase activity of CDKs and cyclins were analyzed using a newly developed assay system.

Results

In the cell lines, biological response to paclitaxel in vitro did not accurately predict sensitivity to paclitaxel in vivo. Among the breast cancer xenograft tumors, however, tumors with significantly increased CDK1 specific activity after paclitaxel treatment were sensitive to paclitaxel in vivo, whereas tumors without such an increase were resistant to paclitaxel in vivo. Baseline CDK2 specific activity was higher in tumors that were sensitive to paclitaxel than in tumors that were resistant to paclitaxel.

Conclusions

The change in CDK1 specific activity of xenograft tumors after paclitaxel treatment and the CDK2 specific activity before paclitaxel treatment are both associated with the drug sensitivity in vivo. Analysis of cyclin-dependent kinase activity in the clinical setting could be a powerful approach for predicting paclitaxel sensitivity.

Ki67 and salivary cancer

We examined Ki67 expression in salivary malignancies of 75 patients with a follow-up period of up to 20 years. Correlations between enhanced Ki67 and enhanced p53 and TUNEL and heparanase staining levels were significant. Median survival for reduced-stained-tumor patients (< or = 5%) was 163 months, dropping significantly to 39 months (p = 0.0005) for enhanced stained tumors (> 5%); 5 year survival probability was 93% and 33%, respectively, 45% and 16%, respectively, (p = 0.0005) at 20 years. Significant correlation between poor survival and concurrently altered expression rates of Ki67 and p53, p27 Skp2, TUNEL and heparanase in the salivary malignancies indicates a biological role in salivary cancer pathogenesis.

Multiple biomarkers in molecular oncology. II. Molecular diagnostics applications in breast cancer management

In recent years, the application of genomic and proteomic technologies to the problem of breast cancer prognosis and the prediction of therapy response have begun to yield encouraging results. Independent studies employing transcriptional profiling of primary breast cancer specimens using DNA microarrays have identified gene expression profiles that correlate with clinical outcome in primary breast biopsy specimens. Recent advances in microarray technology have demonstrated reproducibility, making clinical applications more achievable. In this regard, one such DNA microarray device based upon a 70-gene expression signature was recently cleared by the US FDA for application to breast cancer prognosis. These DNA microarrays often employ at least 70 gene targets for transcriptional profiling and prognostic assessment in breast cancer. The use of PCR-based methods utilizing a small subset of genes has recently demonstrated the ability to predict the clinical outcome in early-stage breast cancer. Furthermore, protein-based immunohistochemistry methods have progressed from using gene clusters and gene expression profiling to smaller subsets of expressed proteins to predict prognosis in early-stage breast cancer. Beyond prognostic applications, DNA microarray-based transcriptional profiling has demonstrated the ability to predict response to chemotherapy in early-stage breast cancer patients. In this review, recent advances in the use of multiple markers for prognosis of disease recurrence in early-stage breast cancer and the prediction of therapy response will be discussed.

Correlation of ultrasound findings with histology, tumor grade, and biological markers in breast cancer

BACKGROUND AND PURPOSE

Ultrasound has been used successfully to differentiate benign and malignant breast lesions. The aim of this study was to investigate the correlation between ultrasound and prognostic indicators in breast cancer such as histological type, tumor grade, and biological markers.

MATERIALS AND METHODS

Ultrasound findings (shape, margin, orientation, boundary, echo pattern, posterior acoustic feature, and presence of calcifications) of 458 breast cancers were analyzed and correlated with the tumor type, tumor grade, and biological markers by univariate and multivariate logistic regression analyses. The biological markers were estrogen receptor, progesterone receptor, and HER-2/neu.

RESULTS

Invasive cancers displayed more frequently an irregular shape, a not parallel orientation, and a hypoechoic or complex echo pattern than carcinoma in situ cases (p < 0.05). Poorly differentiated invasive cancers had more frequently not circumscribed margins, an abrupt boundary, and a hypoechoic or complex echo pattern than moderately/well differentiated cancers (p < 0.05). Estrogen or progesterone receptor negative cancers more often displayed a hypoechoic or complex echo pattern and HER-2/neu positive cancers had more calcifications (p < 0.05).

CONCLUSION

Ultrasound pattern is correlated with tumor type, tumor grade, and biological markers in breast cancers and it may be useful for prediction of prognosis.

Commercialized multigene predictors of clinical outcome for breast cancer

In the past 5 years, a number of commercialized multigene prognostic and predictive tests have entered the complex and expanding landscape of breast cancer companion diagnostics. These tests have used a variety of formats ranging from the familiar slide-based assays of immunohistochemistry and fluorescence in situ hybridization to the nonmorphology-driven molecular platforms of quantitative multiplex real-time polymerase chain reaction and genomic microarray profiling. In this review, 14 multigene assays are evaluated as to their scientific validation, current clinical utility, regulatory approval status, and estimated cost-benefit ratio. Emphasis is placed on two tests: oncotype DX and MammaPrint. Current evidence indicates that the oncotype DX test has the advantages of earlier commercial launch, wide acceptance for payment by third-party payors in the U.S., ease of use of formalin-fixed paraffin-embedded tissues, recent listing by the American Society of Clinical Oncology Breast Cancer Tumor Markers Update Committee as recommended for use, continuous scoring system algorithm, ability to serve as both a prognostic test and predictive test for certain hormonal and chemotherapeutic agents, demonstrated cost-effectiveness in one published study, and a high accrual rate for the prospective validation clinical trial (Trial Assigning Individualized Options for Treatment). The MammaPrint assay has the advantages of a 510(k) clearance by the U.S. Food and Drug Administration, a larger gene number, which may enhance further utility, and a potentially wider patient eligibility, including lymph node-positive, estrogen receptor (ER)-negative, and younger patients being accrued into the prospective trial (Microarray in Node-Negative Disease May Avoid Chemotherapy). A number of other assays have specific predictive goals that are most often focused on the efficacy of tamoxifen in ER-positive patients, such as the two-gene ratio test and the cytochrome P450 CYP2D6 genotyping assay.

Identification of a gene signature in cell cycle pathway for breast cancer prognosis using gene expression profiling data

Background

Numerous studies have used microarrays to identify gene signatures for predicting cancer patient clinical outcome and responses to chemotherapy. However, the potential impact of gene expression profiling in cancer diagnosis, prognosis and development of personalized treatment may not be fully exploited due to the lack of consensus gene signatures and poor understanding of the underlying molecular mechanisms.

Methods

We developed a novel approach to derive gene signatures for breast cancer prognosis in the context of known biological pathways. Using unsupervised methods, cancer patients were separated into distinct groups based on gene expression patterns in one of the following pathways: apoptosis, cell cycle, angiogenesis, metastasis, p53, DNA repair, and several receptor-mediated signaling pathways including chemokines, EGF, FGF, HIF, MAP kinase, JAK and NF-κB. The survival probabilities were then compared between the patient groups to determine if differential gene expression in a specific pathway is correlated with differential survival.

Results

Our results revealed expression of cell cycle genes is strongly predictive of breast cancer outcomes. We further confirmed this observation by building a cell cycle gene signature model using supervised methods. Validated in multiple independent datasets, the cell cycle gene signature is a more accurate predictor for breast cancer clinical outcome than the previously identified Amsterdam 70-gene signature that has been developed into a FDA approved clinical test MammaPrint^®.

Conclusion

Taken together, the gene expression signature model we developed from well defined pathways is not only a consistently powerful prognosticator but also mechanistically linked to cancer biology. Our approach provides an alternative to the current methodology of identifying gene expression markers for cancer prognosis and drug responses using the whole genome gene expression data.

Exploring the anti-tumour activity of bisphosphonates in early breast cancer

Bisphosphonates are potent inhibitors of osteoclast-mediated bone resorption and are firmly established in the management of breast cancer patients with metastatic skeletal disease. There are extensive data that bisphosphonates, particularly nitrogen-containing bisphosphonates such as zoledronic acid, exhibit anti-tumour activity potentially via both indirect and direct mechanisms in vitro. In vivo studies using animal models of breast cancer induced bone disease have shown that bisphosphonates exert anti-tumour effects via inhibiting osteolysis and reducing skeletal tumour burden. Furthermore, pre-clinical studies have demonstrated synergistic anti-tumour effects between chemotherapy agents commonly used in breast cancer treatment and nitrogen-containing bisphosphonates. This, coupled with emerging evidence from pre-clinical in vivo studies suggesting that bisphosphonates may have additional anti-tumour activity outside of the bone microenvironment, could be of significant importance in the clinical management of breast cancer. The evidence in favour of an anti-tumour effect of bisphosphonates in the clinical setting is inconclusive however, with conflicting evidence from several trials. This review focuses on the anti-tumour activity of bisphosphonates in breast cancer, with particular focus on zoledronic acid. The pre-clinical evidence for anti-tumour activity will be reviewed, followed by the synergistic effects with anti-cancer agents. Finally, the clinical relevance and strategies for the evaluation of anti-tumour activity in breast cancer will be discussed. We are currently exploring the potential synergistic anti-tumour effects of the sequential treatment of neoadjuvant chemotherapy followed by zoledronic acid in a randomised phase II study evaluating biological endpoints including apoptosis, proliferation and angiogenesis in patients with breast cancer.

Genomic instability and proliferative activity as risk factors for distant metastases in breast cancer

The role of genomic instability and proliferative activity for development of distant metastases in breast cancer was analysed, and the relative contribution of these two risk factors was quantified. A detailed quantitative comparison was performed between Ki67 and cyclin A as proliferative markers. The frequency of Ki67 and cyclin A-positive cells was scored in the same microscopic areas in 428 breast tumours. The frequency of Ki67-positive cells was found to be highly correlated with the frequency of cyclin A-positive cells, and both proliferation markers were equally good to predict risk of distant metastases. The relative contribution of degree of aneuploidy and proliferative activity as risk markers for developing distant metastases was studied independently. Although increased proliferative activity in general was associated with an increased risk of developing distant metastases, ploidy level was found to be an independent and even stronger marker when considering the group of small (T1) node negative tumours. By combining proliferative activity and ploidy level, a large group of low risk breast tumours (39%) could be identified in which only a few percentage of the tumours (5%) developed distant metastases during the 9-year follow-up time period.

Imaging of cell proliferation: status and prospects

Increased cellular proliferation is an integral part of the cancer phenotype. Several in vitro assays have been developed to measure the rate of tumor growth, but these require biopsies, which are particularly difficult to obtain over time and in different areas of the body in patients with multiple metastatic lesions. Most of the effort to develop imaging methods to noninvasively measure the rate of tumor cell proliferation has focused on the use of PET in conjunction with tracers for the thymidine salvage pathway of DNA synthesis, because thymidine contains the only pyrimidine or purine base that is unique to DNA. Imaging with 11C-thymidine has been tested for detecting tumors and tracking their response to therapy in animals and patients. Its major limitations are the short half-life of 11C and the rapid catabolism of thymidine after injection. These limitations led to the development of analogs that are resistant to degradation and can be labeled with radionuclides more conducive to routine clinical use, such as 18F. At this point, the thymidine analogs that have been studied the most are 3'-deoxy-3'-fluorothymidine (FLT) and 1-(2'-deoxy-2'-fluoro-1-beta-d-arabinofuranosyl)-thymine (FMAU). Both are resistant to degradation and track the DNA synthesis pathway. FLT is phosphorylated by thymidine kinase 1, thus being retained in proliferating cells. It is incorporated by the normal proliferating marrow and is glucuronidated in the liver. FMAU can be incorporated into DNA after phosphorylation but shows less marrow uptake. It shows high uptake in the normal heart, kidneys, and liver, in part because of the role of mitochondrial thymidine kinase 2. Early clinical data for 18F-FLT demonstrated that its uptake correlates well with in vitro measures of proliferation. Although 18F-FLT can be used to detect tumors, its tumor-to-normal tissue contrast is generally lower than that of 18F-FDG in most cancers outside the brain. The most promising use for thymidine and its analogs is in monitoring tumor treatment response, as demonstrated in animal studies and pilot human trials. Further work is needed to determine the optimal tracer(s) and timing of imaging after treatment.

Proliferation markers and survival in early breast cancer: a systematic review and meta-analysis of 85 studies in 32,825 patients

We have performed a systematic review and meta-analysis of proliferation markers (Ki-67, mitotic index (MI), proliferating cell nuclear antigen (PCNA) and thymidine or bromodeoxyuridine labelling index (LI)) with respect to survival in early breast cancer. Eighty-five studies involving 32,825 patients were analysed. Ki-67 (43 studies, 15,790 patients), MI (20 studies, 7021 patients), and LI (11 studies, 7337 patients) were associated with significantly shorter overall and disease free survival, using results from univariate and multivariate analyses from the individual studies. PCNA (11 studies, 2677 patients) was associated with shorter overall survival by multivariate analysis only, because of lack of data. There was some evidence for publication bias, but all markers remained significant after allowing for this. Ki-67, MI, PCNA and LI are associated with worse survival outcomes in early breast cancer. However, whether these proliferation markers provide additional prognostic information to commonly used prognostic indices remains unclear.

Daintain/AIF-1 promotes breast cancer proliferation via activation of the NF-kappaB/cyclin D1 pathway and facilitates tumor growth

Recent research indicates that inflammatory factors play important roles in the initiation and progression of cancers, including breast cancer. Daintain/allograft inflammatory factor-1 (AIF-1) is a crucial mediator in the inflammatory response, but it has not yet been reported whether daintain/AIF-1 is involved in the development of breast cancers. In this study, immunohistochemical analysis found strong positive expression of daintain/AIF-1 in breast ductal tumor epithelia, but only weakly positive or negative expression in the adjacent histologically normal ductal epithelia. Then, the effect of daintian/AIF-1 on the proliferation of the breast cancer cell line MDA-MB-231 was explored via transduction of the daintian/AIF-1 gene into the cells, and via inhibition of the expression of daintain/AIF-1 through short interference RNA. The results demonstrated that up-regulation and down-regulation of daintain/AIF-1 expressions promoted and inhibited the proliferation of MDA-MB-231, respectively. More interestingly, daintain/AIF-1 overexpression facilitated tumor growth in female nude mice. Furthermore, we found that daintain/AIF-1 overexpression up-regulated the expression of cyclin D1 and enhanced the transcriptional activity of nuclear factor-kappa B (NF-kappaB), a regulator of cyclin D1 expression. In contrast, the down-regulation of daintain/AIF-1 expression decreased cyclin D1 expression and inhibited the transcriptional activity of NF-kappaB. These results strongly suggest that daintain/AIF-1 can promote the growth of breast tumors via activating NF-kappaB signaling, which consequently up-regulates the expression of cyclin D1, implying that daintain/AIF-1 may be a novel target molecule for the prognosis and therapy of breast cancer.

Signal transduction involving the dmp1 transcription factor and its alteration in human cancer

Dmp1 (cyclin D-interacting myb-like protein 1; also called Dmtf1) is a transcription factor that has been isolated in a yeast two-hybrid screen through its binding property to cyclin D2. Dmp1 directly binds to and activates the Arf promoter and induces Arf-p53-dependent cell cycle arrest in primary cells. D-type cyclins usually inhibit Dmp1-mediated transcription in a Cdk-independent fashion; however, Dmp1 shows synergistic effects with D-cyclins on the Arf promoter. Ras or Myc oncogene-induced tumor formation is accelerated in both Dmp1^+/− and Dmp1^−/− mice with no significant differences between Dmp1^+/− and Dmp1^−/−. Thus, Dmp1 is haplo-insufficient for tumor suppression. Tumors from Dmp1^−/− or Dmp1^+/− mice often retain wild-type Arf and p53, suggesting that Dmp1 is a physiological regulator of the Arf-p53 pathway. The Dmp1 promoter is activated by oncogenic Ras-Raf signaling, while it is repressed by physiological mitogenic stimuli, overexpression of E2F proteins, and genotoxic stimuli mediated by NF-κB. The human DMP1 gene (hDMP1) is located on chromosome 7q21 and is hemizygously deleted in approximately 40% of human lung cancers, especially those that retain normal INK4a/ARF and P53 loci. Thus, hDMP1 is clearly involved in human carcinogenesis, and tumors with hDMP1 deletion may constitute a discrete disease entity.

Validating the prognostic value of proliferation measured by Phosphohistone H3 (PPH3) in invasive lymph node-negative breast cancer patients less than 71 years of age

We validated and compared the prognostic value of the proliferation marker phosphohistone H3 (PPH3) with classical variables in 241 T(1-2)N(0)M(0) breast cancer patients less than 71 years old with long-term follow-up (median 117 months) and without adjuvant treatment. PPH3 was measured by automated digital image analysis. Thirty-seven patients (15%) developed distant metastases and 29 (12%) died. The previously established PPH3 prognostic threshold H3 <13 (n = 157; 65% of all cases) vs. >or=13 (n = 84; 35% of all cases) was the strongest prognostic threshold exceeding all other characteristics, with 10-year recurrence-free survival of distant metastases of 96 and 64%, respectively (P = < 0.0001, hazard ratio = 7.8, 95% confidence interval = 3.4-17.9). PPH3 is robust as it showed high inter-observer reproducibility and was prognostic over wide range of thresholds around 13 and is the strongest prognostic variable in invasive node-negative breast cancer patients less than 71 years old.

Sclareol induces apoptosis in human HCT116 colon cancer cells in vitro and suppression of HCT116 tumor growth in immunodeficient mice

Labd-14-ene-8, 13-diol (sclareol) is a labdane-type diterpene, which has demonstrated significant cytotoxic activity against human leukemic cell lines, but its effect on solid tumor-derived cells is uknown. Here, we demonstrate that addition of sclareol to cultures of human colon cancer HCT116 cells results in inhibition of DNA synthesis, arrest of cells at the G(1) phase of the cell cycle, activation of caspases-8, -9, PARP degradation, and DNA fragmentation, events characteristic of induction of apoptosis. Intraperitoneal (ip) administration of sclareol alone, at the maximum tolerated dose, was unable to induce suppression of growth of HCT116 tumors established as xenografts in immunodeficient SCID mice. In contrast, ip administration of liposome-encapsulated sclareol, following a specific schedule, induced suppression of tumor growth by arresting tumor cell proliferation as assessed by detecting the presence of the cell proliferation-associated nuclear protein, Ki67, in thin tumor sections. These findings suggest that sclareol incorporated into liposomes may possess chemotherapeutic potential for the treatment of colorectal and other types of human cancer.

Identification of a subset of breast carcinomas characterized by expression of cytokeratin 15: relationship between CK15+ progenitor/amplified cells and pre-malignant lesions and invasive disease

Recently, we presented evidence--based on the analysis of benign hyperproliferative lesions of the breast--for the presence of cells that express the stem cell marker cytokeratin (CK) 15 in combination with CK19, a protein widely expressed by mammary epithelial cells. Here we report the finding of a subset of breast carcinomas characterized by expression of CK15. CK15 expressing tumors constituted 5% (6 out of 120; 4 of ductal type and 2 of lobular type) of the high-risk breast carcinomas examined by gel-based proteomics and immunohistochemistry. Five out of the six CK15+ carcinomas were CK15+/CK19-. The remaining tumor was mainly composed of cells expressing both CK15 and CK19 (CK15+/CK19+), but it also contained invasive areas with cells expressing only one of these makers (CK15+/CK19- and CK15-/CK19+ cells). To address the relationship between putative luminal progenitor/amplified CK15+ cells and malignant disease, and to determine whether cells/lesions lose expression of CK15 as a result of tumour initiation and/or progression, we searched among our sample set for carcinomas in which invasive tumor areas co-existed with non-malignant cells and hyperproliferative and known pre-malignant lesions. Only one such tumour was found (T71), a CK15-/CK19+/p53+ carcinoma that contained p53 negative non-malignant epithelial cells exhibiting a variety of, CK15/CK19 cellular phenotypes (CK15+/CK19+; CK15+/CK19-; CK15-/CK19+; CK15-/CK19-), often associated with simple columnar cells. Single layers of epithelial cells exhibiting all four CK15/CK19 phenotypes were observed contiguous to areas of atypical ductal hyperplasia that contained p53 positive cells that lost CK15 expression (CK15-/CK19+) and had a very similar phenotype to those of the neighboring ductal carcinoma in situ (DCIS) and invasive cells. The undifferentiated CK15+/CK19+ cells, which had the phenotype CK15+/CK19+/CK14+/CK8+ and -/ER-/PgR-/AR-/CD44+ (weak)/CK17-/p63-/vimentin+/Ki67-/Bcl-2+ (weak)/GATA-3-/p53-, most likely correspond to lineage-restricted luminal progenitor cells able to generate the other more differentiated CK15/CK19 cellular phenotypes, thus giving rise to the daunting intratumour heterogeneity displayed by carcinoma T71. Cells with a very similar phenotype to the CK15+/CK19+ progenitor cells were observed in a juvenile fibroadenoma as well as in the large collecting ducts of the breast. The latter, however, expressed in addition CK14 and had a phenotype (CK15+/CK19+/CK14+/CK8+ (weak)/ER-/PgR-/AR-/CD44+ (weak)/CK17-/p63-/vimentin-/Ki67-/Bcl-2+/GATA-3-/p53-) that resembled that of the putative normal adult breast stem cells as inferred from published data. Further molecular characterization of these progenitor cells as well as unraveling of the signaling pathways that regulate their growth and differentiation may prove invaluable for developing novel therapeutic strategies that target cancer at an early stage.

Phosphohistone H3 expression has much stronger prognostic value than classical prognosticators in invasive lymph node-negative breast cancer patients less than 55 years of age

The proliferation factor mitotic activity index is the strongest prognostic factor in early breast cancer, but it may lack reproducibility. We analyzed the prognostic value of phosphohistone H3, a marker of cells in late G(2) and M phase, measuring highly standardized immunohistochemical nuclear phosphohistone H3 expression by subjective counts and digital image analysis. Expression was compared with classical clinico-pathologic prognostic variables and the mitotic activity index in 119 node-negative invasive breast cancers in patients less than 55 years old treated with adjuvant systemic chemotherapy with long-term follow-up (median 168 months). Nineteen patients (16%) developed distant metastases and 16 (13%) died. Strong phosphohistone H3 expression occurred preferentially in the peripheral growing front; counts were highly reproducible between observers (R=0.92) and highly consistent with digital image analysis (R=0.96). Phosphohistone H3 correlated (P<0.05) with tumor diameter, estrogen receptor, carcinoma grade, and mitotic activity index. Phosphohistone H3 values were systematically (80%) higher than the mitotic activity index. Receiver-operating curve analysis objectively showed that phosphohistone H3 <13 (n=53; 45% of all cases) vs phosphohistone H3> or =13 (n=66; 55% of all cases) was the strongest prognostic threshold, with 20-year recurrence-free survival of distant metastases of 96 and 58%, respectively (P=0.0002, HR=9.6). Mitotic activity index was the second strongest prognostic variable (P=0.003, HR=3.9). In multivariate analysis, phosphohistone H3 <13 vs> or =13 exceeded the prognostic value of the mitotic activity index. None of the other classical prognostic factors examined offered prognostic value additional to phosphohistone H3. Phosphohistone H3 is by far the strongest prognostic variable in early invasive node-negative breast cancer patients less than 55 years old with long-term follow-up.

Low E2F1 transcript levels are a strong determinant of favorable breast cancer outcome

Introduction

We investigated whether mRNA levels of E2F1, a key transcription factor involved in proliferation, differentiation and apoptosis, could be used as a surrogate marker for the determination of breast cancer outcome.

Methods

E2F1 and other proliferation markers were measured by quantitative RT-PCR in 317 primary breast cancer patients from the Stiftung Tumorbank Basel. Correlations to one another as well as to the estrogen receptor and ERBB2 status and clinical outcome were investigated. Results were validated and further compared with expression-based prognostic profiles using The Netherlands Cancer Institute microarray data set reported by Fan and colleagues.

Results

E2F1 mRNA expression levels correlated strongly with the expression of other proliferation markers, and low values were mainly found in estrogen receptor-positive and ERBB2-negative phenotypes. Patients with low E2F1-expressing tumors were associated with favorable outcome (hazard ratio = 4.3 (95% confidence interval = 1.8–9.9), P = 0.001). These results were consistent in univariate and multivariate Cox analyses, and were successfully validated in The Netherlands Cancer Institute data set. Furthermore, E2F1 expression levels correlated well with the 70-gene signature displaying the ability of selecting a common subset of patients at good prognosis. Breast cancer patients' outcome was comparably predictable by E2F1 levels, by the 70-gene signature, by the intrinsic subtype gene classification, by the wound response signature and by the recurrence score.

Conclusion

Assessment of E2F1 at the mRNA level in primary breast cancer is a strong determinant of breast cancer patient outcome. E2F1 expression identified patients at low risk of metastasis irrespective of the estrogen receptor and ERBB2 status, and demonstrated similar prognostic performance to different gene expression-based predictors.

Survival after negative sentinel lymph node biopsy in breast cancer at least equivalent to after negative extensive axillary dissection

AIM

Sentinel lymph node biopsy (SLNB) without completion axillary lymph node dissection (ALND) is replacing ALND as the axillary staging procedure of choice in breast cancer patients with a clinically negative axilla even though it is unclear whether this influences patient survival. Our aim was to compare the survival of breast cancer patients with a negative SLNB without completion ALND to that of extensive ALND-negative patients.

METHODS

Eindhoven Cancer Registry data on breast cancer patients diagnosed between 1989 and 2002 with follow-up to 1 January 2005 was used. Survival was compared between 880 SLNB-negative women (median follow-up 3.6years) without completion ALND and 1681 ALND-negative women (median follow-up 7.7years) with at least 10 axillary nodes removed. Conclusions were made after correcting for age, tumour size, tumour location, tumour histology, tumour grade, mitotic activity index (MAI), hormone receptor status, and local and systemic treatment in uni- and multivariate analyses.

RESULTS

Crude 5-year survival rates were 85% for ALND-negative and 89% for SLNB-negative breast cancer patients (p=0.026). After correction for potential confounders in a multivariate Cox regression analyses, the hazard ratio for overall mortality of ALND-negative compared to SLNB-negative patients without completion ALND was 1.23 (95% confidence interval: 0.93-1.64).

CONCLUSION

Survival after a SLNB without completion ALND is at least equivalent to after an extensive ALND in node-negative breast cancer patients. This means that the SLNB only can safely replace ALND as the procedure of choice for axillary staging in breast cancer patients with a clinically negative axilla.

Aggressive breast cancer cells are dependent on activated Abl kinases for proliferation, anchorage-independent growth and survival

Mutant Abl kinases (such as BCR-Abl) drive the development of leukemia; however little is known regarding whether Abl kinases contribute to the development or progression of solid tumors. We recently demonstrated that endogenous Abl kinases (c-Abl, Arg) are activated by deregulated ErbB receptors and Src kinases, and drive invasion of aggressive breast cancer cells. In this study, we examined whether activation of endogenous Abl kinases affects transformation, proliferation and survival, which are major contributors to breast cancer development and metastatic progression. Using a pharmacological inhibitor and RNAi, we demonstrate that activation of endogenous Abl kinases dramatically promotes breast cancer cell proliferation and anchorage-independent growth in serum, as well as survival following nutrient deprivation. Activation of Abl kinases mediates phosphorylation of STAT3, and promotes proliferation by accelerating G(1) --> S progression. Moreover, we identify IGF-1R as a novel upstream activator of endogenous Abl kinases, and demonstrate that Abl kinase activation is required for IGF-1-stimulated cell cycle progression in breast cancer cells. Since activation of Abl kinases affects multiple steps of breast cancer development and progression, Abl kinase inhibitors are likely to be effective agents for the treatment of breast cancers containing highly active Abl kinases.

Proteomics analysis of conditioned media from three breast cancer cell lines: a mine for biomarkers and therapeutic targets

A "bottom-up" proteomics approach and a two-dimensional (strong cation exchange followed by reversed-phase) LC-MS/MS strategy on a linear ion trap (LTQ) were utilized to identify and compare expressions of extracellular and membrane-bound proteins in the conditioned media of three breast cell lines (MCF-10A, BT474, and MDA-MB-468). Proteomics analysis of the media identified in excess of 600, 500, and 700 proteins in MCF-10A, BT474, and MDA-MB-468, respectively. We successfully identified the internal control proteins, kallikreins 5, 6, and 10 (ranging in concentration from 2 to 50 microg/liter) in MDA-MB-468 conditioned medium as validated by ELISA and confidently identified Her-2/neu in BT474 cells. Subcellular localization was determined based on Genome Ontology terms for all the 1,139 proteins of which 34% were classified as extracellular and membrane-bound. Proteomics analysis of MDA-MB-468 cell lysate demonstrated that only 5% of all identified proteins were extracellular. This confirmed our hypothesis that examining the CM of cell lines, as opposed to the cell lysates, leads to a significant enrichment in secreted proteins. Tissue specificity, functional classifications, and spectral counting were performed. Elafin, a protease inhibitor, identified in the conditioned media of BT474 and MDA-MB-468 and the three kallikreins (KLK5, KLK6, and KLK10) were validated using an immunoassay on various serum and biological samples. Some of the secreted proteins identified have established roles in breast cancer development (cell growth, differentiation, and metastasis) and/or are linked to early onset breast cancer. Our approach to mining for low abundance molecules could identify proteins in various stages of breast cancer development. Many of the identified proteins are potentially useful to investigate as circulating serum breast cancer biomarkers.

Nuclear cyclin B1 in human breast carcinoma as a potent prognostic factor

Cyclin B1 is translocated to the nucleus from the cytoplasm, and plays an essential role in cell proliferation through promotion of mitosis. Although overexpression of cyclin B1 was previously reported in breast carcinomas, the biological significance of the intracellular localization of cyclin B1 remains unclear. Therefore, in this study, we examined cyclin B1 immunoreactivity in 109 breast carcinomas, according to the intracellular localization, that is, nucleus, cytoplasm or total (nucleus or cytoplasm). Total cyclin B1 was detected in carcinoma cells in 42% of breast carcinomas examined, whereas nuclear and cytoplasmic cyclin B1 were positive in 17 and 35% of the cases, respectively. Total or cytoplasmic cyclin B1 were positively associated with histological grade, mitosis, Ki-67, p53, c-myc or 14-3-3sigma, and inversely correlated with estrogen or progesterone receptor. Nuclear cyclin B1 was significantly associated with tumor size, lymph node metastasis, histological grade, mitosis, Ki-67 or polo-like kinase 1. Only nuclear cyclin B1 was significantly associated with adverse clinical outcome of the patients, and multivariate analyses of disease-free and overall survival demonstrated nuclear cyclin B1 as the independent marker. A similar tendency was detected in the patients receiving adjuvant therapy after surgery. These results suggest that an onocogenic role of overexpressed cyclin B1 is mainly mediated in nuclei of breast carcinoma cells, and the nuclear translocation is regulated by polo-like kinase 1 and 14-3-3sigma. Nuclear cyclin B1-positive breast carcinoma is resistant to adjuvant therapy, and nuclear cyclin B1 immunoreactivity is a potent prognostic factor in breast carcinoma patients.

A mathematical model of breast cancer development, local treatment and recurrence

Cancer development is a stepwise process through which normal somatic cells acquire mutations which enable them to escape their normal function in the tissue and become self-sufficient in survival. The number of mutations depends on the patient's age, genetic susceptibility and on the exposure of the patient to carcinogens throughout their life. It is believed that in every malignancy 4-6 crucial similar mutations have to occur on cancer-related genes. These genes are classified as oncogenes and tumour suppressor genes (TSGs) which gain or lose their function respectively, after they have received one mutative hit or both of their alleles have been knocked out. With the acquisition of each of the necessary mutations the transformed cell gains a selective advantage over normal cells, and the mutation will spread throughout the tissue via clonal expansion. We present a simplified model of this mutation and expansion process, in which we assume that the loss of two TSGs is sufficient to give rise to a cancer. Our mathematical model of the stepwise development of breast cancer verifies the idea that the normal mutation rate in genes is only sufficient to give rise to a tumour within a clinically observable time if a high number of breast stem cells and TSGs exist or genetic instability is involved as a driving force of the mutation pathway. Furthermore, our model shows that if a mutation occurred in stem cells pre-puberty, and formed a field of cells with this mutation through clonal formation of the breast, it is most likely that a tumour will arise from within this area. We then apply different treatment strategies, namely surgery and adjuvant external beam radiotherapy and targeted intraoperative radiotherapy (TARGIT) and use the model to identify different sources of local recurrence and analyse their prevention.

Predictors of axillary lymph node metastasis in breast cancer: A systematic review

AIMS

To review the established and emerging techniques in axillary lymph node prediction and explore their potential impact on clinical practice. To reliably identify patients in whom axillary lymph node surgery, including SLNB, can be safely omitted.

METHODS

Searches of PubMed were made using the search terms "axilla" (or "axillary"), "lymph", "node" and "predictor" (or "prediction"). Articles from abstracts and reports from meetings were included only when they related directly to previously published work.

FINDINGS

There are numerous studies in which the predictive utility of biomarkers as determinants of axillary lymph node status have been investigated. Few of these have specifically addressed the attributes of the primary tumour which could offer much potential for the prediction of tumour metastasis to the axillary lymph nodes.

CONCLUSIONS

Currently, no single marker is sufficiently accurate to obviate the need for formal axillary staging using SLNB or axillary clearance.

Characterization of breast precancerous lesions and myoepithelial hyperplasia in sclerosing adenosis with apocrine metaplasia

The identification as well as the molecular characterization of breast precancerous lesions in terms of increased risk of progression and/or recurrence is becoming a critical issue today as improved non-surgical procedures are detecting cancer at an earlier stage. The strategy we have been pursuing to identify early apocrine breast lesions is based on the postulate that invasive apocrine carcinomas evolve from epithelial cells in terminal duct lobular units (TDLUs) in a stepwise manner that involves apocrine metaplasia of normal breast epithelia, hyperplasia, atypia, and apocrine carcinoma in situ. First, we identify specific protein biomarkers for benign apocrine metaplasia and thereafter we search for biomarkers that are highly overexpressed by pure invasive apocrine carcinomas. Here we present studies in which we have used antibodies against components of a benign apocrine signature that includes 15-prostaglandin dehydrogenase (15-PGDH), a protein that is expressed by all benign apocrine lesions, and markers that are highly overexpressed by pure invasive apocrine carcinomas such as MRP14 (S100A9), psoriasin (S100A7), and p53 to identify precancerous lesions in sclerosing adenosis (SA) with apocrine metaplasia. The latter is a benign proliferative lesion of the breast that exhibits an increase in the size of the TDLUs and characterized by retained two-cell lining, and myoepithelial (ME) and stromal hyperplasia. SA with apocrine metaplasia, i.e. apocrine adenosis (AA), presents with a higher degree of atypical apocrine hyperplasia, and these lesions are believed to be precursors of apocrine carcinoma, in situ and invasive. Analysis of 24 selected SA samples with apocrine metaplasia revealed non-obligate putative apocrine precancerous lesions that displayed some, or in same cases all the three markers associated with pure invasive apocrine carcinomas. These studies also revealed p53 positive, non-apocrine putative precancerous lesions as well as novel phenotypes for ME and some luminal cells characterized by the expression of cytokeratin 15.

Imaging early changes in proliferation at 1 week post chemotherapy: a pilot study in breast cancer patients with 3′-deoxy-3′-[18F]fluorothymidine positron emission tomography

PURPOSE

3'-deoxy-3'-[18F]fluorothymidine positron emission tomography ([18F]FLT-PET) has been developed for imaging cell proliferation and findings correlate strongly with the Ki-67 labelling index in breast cancer. The aims of this pilot study were to define objective criteria for [18F]FLT response and to examine whether [18F]FLT-PET can be used to quantify early response of breast cancer to chemotherapy.

METHODS

Seventeen discrete lesions in 13 patients with stage II-IV breast cancer were scanned prior to and at 1 week after treatment with combination 5-fluorouracil, epirubicin and cyclophosphamide (FEC) chemotherapy. The uptake at 90 min (SUV90) and irreversible trapping (Ki) of [18F]FLT were calculated for each tumour. The reproducibility of [18F]FLT-PET was determined in nine discrete lesions from eight patients who were scanned twice before chemotherapy. Clinical response was assessed at 60 days after commencing FEC.

RESULTS

All tumours showed [18F]FLT uptake and this was reproducible in serial measurements (SD of mean % difference=10.5% and 15.1%, for SUV90 and Ki, respectively; test-retest correlation coefficient>or=0.97). Six patients had a significant clinical response (complete or partial) at day 60; these patients also had a significant reduction in [18F]FLT uptake at 1 week. Decreases in Ki and SUV90 at 1 week discriminated between clinical response and stable disease (p=0.022 for both parameters). In three patients with multiple lesions there was a mixed [18F]FLT response in primary tumours and metastases. [18F]FLT response generally preceded tumour size changes.

CONCLUSION

[18F]FLT-PET can detect changes in breast cancer proliferation at 1 week after FEC chemotherapy.

Loss of expression of FANCD2 protein in sporadic and hereditary breast cancer

Fanconi anemia (FA) is a recessive disorder associated with progressive pancytopenia, multiple developmental defects, and marked predisposition to malignancies. FA is genetically heterogeneous, comprising at least 12 complementation groups (A–M). Activation of one of the FA proteins (FANCD2) by mono-ubiquitination is an essential step in DNA damage response. As FANCD2 interacts with BRCA1, is expressed in proliferating normal breast cells, and FANCD2 knockout mice develop breast tumors, we investigated the expression of FANCD2 in sporadic and hereditary invasive breast cancer patients to evaluate its possible role in breast carcinogenesis. Two tissue microarrays of 129 and 220 sporadic breast cancers and a tissue microarray containing 25 BRCA1 germline mutation-related invasive breast cancers were stained for FANCD2. Expression results were compared with several clinicopathological variables and tested for prognostic value. Eighteen of 96 (19%) sporadic breast cancers and two of 21 (10%) BRCA1-related breast cancers were completely FANCD2-negative, which, however, still showed proliferation. In the remaining cases, the percentage of FANCD2-expressing cells correlated strongly with mitotic index and percentage of cells positive for the proliferation markers Ki-67 and Cyclin A. In immunofluorescence double staining, coexpression of FANCD2 and Ki-67 was apparent. In survival analysis, high FANCD2 expression appeared to be prognostically unfavorable for overall survival (p = 0.03), independent from other major prognosticators (p = 0.026). In conclusion, FANCD2 expression is absent in 10–20% of sporadic and BRCA1-related breast cancers, indicating that somatic inactivating (epi)genetic events in FANCD2 may be important in both sporadic and hereditary breast carcinogenesis. FANCD2 is of independent prognostic value in sporadic breast cancer.

Measuring proliferation in breast cancer: practicalities and applications

Various methods are available for the measurement of proliferation rates in tumours, including mitotic counts, estimation of the fraction of cells in S-phase of the cell cycle and immunohistochemistry of proliferation-associated antigens. The evidence, advantages and disadvantages for each of these methods along with other novel approaches is reviewed in relation to breast cancer. The potential clinical applications of proliferative indices are discussed, including their use as prognostic indicators and predictors of response to systemic therapy.

The prognostic value of proliferation in lymph-node-negative breast cancer patients is age dependent

In lymph-node-negative invasive breast cancer patients<55 years, the proliferation marker mitotic activity index (MAI) has previously been shown to be the strongest prognosticator. In studies without age definition, MAI was not strongly prognostic. We investigated the age dependency of the prognostic value of proliferation for distant metastasis-free (MFS) and overall cancer-related survival (OS) in 1004 histologically diagnosed T1-3N0M0 invasive breast cancers (n=516, <55 years; n=322, 55-70 years; n=166, >70 years) without systemic adjuvant therapy and long follow-up (median: 108 months). The MAI decreases with age and the prognostic value of MAI varied by age group. For patients<55 years, hazard ratios (HR) for MAI>or=10 versus<10 for MFS and OS were 3.1 and 4.4, respectively (P<.0001 for both), but only 1.9 and 1.9 (P=.004 and .006) for patients aged 55-70 years, while over 70 years, MAI was not significant (P=.11). The prognostic value of proliferation was age-dependent. Prognostic breast cancer studies must clearly indicate the age group being studied.

Significance of cell kinetic parameters in the prognosis of malignant melanoma: a review

Malignant melanoma has been extensively studied concerning methods of predicting progression and clinical outcome. The maximum tumor thickness as measured by Breslow's method is the cornerstone prognostic criterion, but despite this, evolution of the disease in some patients remains unpredictable, confirming that new reliable prognostic factors are awaited. Cell kinetic evaluation has been shown to be a useful tool for assessing the prognosis of breast and gastrointestinal cancer patients. Indeed, in these fields, the mitotic index and MIB-1 expression index, which are indirect estimates of the growth fraction of tumor cell population, are commonly shown to correlate with tumor grade and patient survival and presented as prognostic factors. In melanoma, results of cell kinetic investigations are conflicting: some studies have established a link between high proliferative activity and a bad prognosis, whereas other reports suggest the opposite. The aim of this review is to discuss these findings.

Cellular automaton simulation examining progenitor hierarchy structure effects on mammary ductal carcinoma in situ

A computer simulation is used to model ductal carcinoma in situ, a form of non-invasive breast cancer. The simulation uses known histological morphology, cell types, and stochastic cell proliferation to evolve tumorous growth within a duct. The ductal simulation is based on a hybrid cellular automaton design using genetic rules to determine each cell's behavior. The genetic rules are a mutable abstraction that demonstrate genetic heterogeneity in a population. Our goal was to examine the role (if any) that recently discovered mammary stem cell hierarchies play in genetic heterogeneity, DCIS initiation and aggressiveness. Results show that simpler progenitor hierarchies result in greater genetic heterogeneity and evolve DCIS significantly faster. However, the more complex progenitor hierarchy structure was able to sustain the rapid reproduction of a cancer cell population for longer periods of time.

The aged breast

There is a clear association between the development of breast cancer and increasing age, with 80% of cancers occurring in women more than 50 years of age and one-third in women over 70 years. Following the menopause the breast undergoes involution, with the main changes affecting the terminal ductal lobular unit. There is an increase in oestrogen receptor alpha (ERalpha)-positive cells, a decrease in proliferation but, in comparison to premenopausal breasts, a greater number of ERalpha-proliferating cells. The breast cancers that occur in women >/= 75 years are more likely to be ER-positive, with a low growth rate and limited expression of HER-2 and p53. It is proposed that uneven involution of the breast, the persistence of at-risk lesions, the presence of ERalpha-proliferating cells and local oestrogen metabolism in breast adipose tissue are factors in the development of breast cancers with a well-differentiated phenotype.

Expression of KLF5 is a prognostic factor for disease-free survival and overall survival in patients with breast cancer

PURPOSE

Kruppel-like factor (KLF5) is a cell growth mediator in various epithelial cells. Higher KLF5 increases cell growth rate and leads to transformed phenotypes. Because tumor cell proliferation is tightly associated with tumor progression, and consequently, with survival of cancer patients, we wanted to examine the prognostic value of KLF5 gene expression for patients with breast cancer.

EXPERIMENTAL DESIGN

The gene expression levels of KLF5, ER, PR, HER2, and MKI67 were quantified in the tumor tissues of 90 patients with breast cancer and correlated with disease-free survival and overall survival of the patients. The correlations of gene expression between KLF5 and ER, PR, HER2, and MKI67 were analyzed. In addition, KLF5 expression was also compared with clinical data and age of patients.

RESULTS

Statistically significant correlations were found between gene expression of KLF5 and both disease-free survival (univariate analysis) and overall survival (univariate and multivariate analysis). Patients with higher KLF5 expression had shorter disease-free survival and overall survival time, whereas patients with lower KLF5 expression had better survival. Moreover, KLF5 was also found to be positively correlated with HER2 and MKI67, and negatively correlated with age of the patients at diagnosis.

CONCLUSION

The gene expression of KLF5 is directly correlated with cell proliferation in vivo and is a prognostic factor for patients with breast cancer. Patients with higher KLF5 expression have shorter disease-free survival and overall survival than patients with lower KLF5 expression. In addition, KLF5 has higher expression in patients ages </=50 years old than in patients >50 years old.

Neoadjuvant chemotherapy in women with large and locally advanced breast cancer: chemoresistance and prediction of response to drug therapy

Patients with large and locally advanced breast cancer (LLABC) present with a therapeutic challenge and undergo multimodality treatment. Many such patients receive neoadjuvant chemotherapy (NAC) prior to surgery. However, a number of these patients do not respond well to NAC and only a percentage (usually less than 30%) obtains a complete or optimal response. A range of mechanisms are believed to be involved in this chemoresistance, including ATP binding cassette (ABC) transporter overexpression, dysregulation of apoptosis and possibly increased numbers of cancer stem cells. The chemoresistant processes may be due to more than one mechanism. The ability to predict a response to NAC would be beneficial, targeting expensive and toxic drug treatment to those likely to respond and providing a therapeutic strategy for further post-operative chemotherapy. Currently, many biomarkers have been studied with a view to establishing a predictor of response. However, no single biomarker appears to be effective. Genomics is a novel biotechnological process which is being used to predict response to drug therapy; this work is currently at an early stage of development

Cell Proliferation in Breast Cancer is a Major Determinant of Clinical Outcome in Node-Positive but Not in Node-Negative Patients

The growth rate of a tumor cell population depends on two major factors: the percentage of proliferating cells (cell growth fraction) and the rapidity of their duplication (cell proliferation rate). The authors evaluated the prognostic and predictive value of both kinetics parameters in a large series of breast cancer patients (n=504). The cell growth fraction was determined by MIB-1 immunostaining, the cell proliferation rate by AgNOR analysis. Ki-67 LI (labeling index) and AgNOR area were significantly associated with histotype, histologic grade, tumor size, estrogen/progesterone receptor status, patient age, and lymph node involvement (P<0.005). In the entire series of patients, both kinetics variables were significantly and independently associated with the clinical outcome, but their prognostic relevance was quite different when node-negative and node-positive patients were considered separately. Although in node-positive patients Ki-67 LI and AgNOR area were the unique independent predictors of disease-free and overall survival, they were excluded by the multivariate Cox model in node-negative patients, where only tumor size and estrogen receptor status retained a significant P-value. These results show that in breast carcinoma the cell growth fraction and the cell proliferation rate have a different prognostic impact with respect to the lymph node status and are major determinants of clinical outcome in node-positive patients only. Within this subgroup, the rapidity of cell proliferation as assessed by AgNOR analysis also served as a sensitive predictor of the response to adjuvant treatments.

KIF14 mRNA expression is a predictor of grade and outcome in breast cancer

Gain of chromosome 1q is a hallmark of breast cancer, and likely reflects oncogene amplification. We previously identified mitotic kinesin KIF14 (kinesin family member 14) as an overexpressed candidate oncogene in the 1q31.3-1q32.1 minimal region of genomic gain in breast cancer cell lines. KIF14 also showed high expression in other cancers, notably an association with survival in lung tumors. We now report KIF14 expression in 99 primary breast tumors and 10 normal breast controls. Measured by real-time RT-PCR, KIF14 was overexpressed 10-fold on average in tumors relative to normals (t test p = 0.000054); expression increased with grade (ANOVA p = 0.000006). Infiltrating ductal carcinomas had higher KIF14 levels than lobular (p = 0.017), and estrogen receptor (ER) negative tumors had higher KIF14 levels than ER positive tumors (t test p = 0.030). KIF14 expression correlated positively with Ki-67 mRNA level (Spearman r = 0.692, p = 0.000001), fraction of positive nodes (r = 0.227, p = 0.024) and percent invasive cells (r = 0.360, p = 0.0002), and negatively with percent fatty stroma (r = -0.258, p = 0.010) and percent normal epithelium (r = -0.291, p = 0.003). KIF14 expression is thus tumor-specific and increased in more aggressive tumors. Indeed, KIF14 expression predicted overall survival (univariate Cox p = 0.010), with an odds ratio of 3.60 (1.37-9.48), in 50 tumors with available outcome data. KIF14 overexpression also predicted decreased disease-free survival (log-rank p = 0.049). These findings are the first evidence of association between expression of a mitotic kinesin and prognostic variables in breast cancer.

Expression of protein elongation factor eEF1A2 predicts favorable outcome in breast cancer

Breast cancer is the most common malignancy among North American women. The identification of factors that predict outcome is key to individualized disease management and to our understanding of breast oncogenesis. We have analyzed mRNA expression of protein elongation factor eEF1A2 in two independent breast tumor populations of size n = 345 and n = 88, respectively. We find that eEF1A2 mRNA is expressed at a low level in normal breast epithelium but is detectably expressed in approximately 50-60% of primary human breast tumors. We have derived an eEF1A2-specific antibody and measured eEF1A2 protein expression in a sample of 438 primary breast tumors annotated with 20-year survival data. We find that high levels of eEF1A2 protein are detected in 60% of primary breast tumors independent of HER-2 protein expression, tumor size, lymph node status, and estrogen receptor (ER) expression. Importantly, we find that high eEF1A2 is a significant predictor of outcome. Women whose tumor has high eEF1A2 protein expression have an increased probability of 20-year survival compared to those women whose tumor does not express substantial eEF1A2. In addition, eEF1A2 protein expression predicts increased survival probability in those breast cancer patients whose tumor is HER-2 negative or who have lymph node involvement.

Expression of Late Cell Cycle Genes and an Increased Proliferative Capacity Characterize Very Early Relapse of Childhood Acute Lymphoblastic Leukemia

PURPOSE

In childhood acute lymphoblastic leukemia (ALL), approximately 25% of patients suffer from relapse. In recurrent disease, despite intensified therapy, overall cure rates of 40% remain unsatisfactory and survival rates are particularly poor in certain subgroups. The probability of long-term survival after relapse is predicted from well-established prognostic factors (i.e., time and site of relapse, immunophenotype, and minimal residual disease). However, the underlying biological determinants of these prognostic factors remain poorly understood.

EXPERIMENTAL DESIGN

Aiming at identifying molecular pathways associated with these clinically well-defined prognostic factors, we did gene expression profiling on 60 prospectively collected samples of first relapse patients enrolled on the relapse trial ALL-REZ BFM 2002 of the Berlin-Frankfurt-Münster study group.

RESULTS

We show here that patients with very early relapse of ALL are characterized by a distinctive gene expression pattern. We identified a set of 83 genes differentially expressed in very early relapsed ALL compared with late relapsed disease. The vast majority of genes were up-regulated and many were late cell cycle genes with a function in mitosis. In addition, samples from patients with very early relapse showed a significant increase in the percentage of S and G(2)-M phase cells and this correlated well with the expression level of cell cycle genes.

CONCLUSIONS

Very early relapse of ALL is characterized by an increased proliferative capacity of leukemic blasts and up-regulated mitotic genes. The latter suggests that novel drugs, targeting late cell cycle proteins, might be beneficial for these patients that typically face a dismal prognosis.