Cathepsin-D in primary breast cancer: prognostic evaluation involving 2810 patients

Reporting Recommendations for Tumor Marker Prognostic Studies (REMARK): explanation and elaboration

The REMARK (Reporting Recommendations for Tumor Marker Prognostic Studies) guideline includes a checklist which aims to improve the reporting of these types of studies. Here, we expand on the REMARK checklist to enhance its use and effectiveness through better understanding of the intent of each item and why the information is important to report. Each checklist item of the REMARK guideline is explained in detail and accompanied by published examples of good reporting. The paper provides a comprehensive overview to educate on good reporting and provide a valuable reference of issues to consider when designing, conducting, and analyzing tumor marker studies and prognostic studies in medicine in general.

The prognostic importance of cathepsin D and E-cadherin in early breast cancer: A single-institution experience

Molecular tools have increasingly been used for decision-making in patients with early breast cancer (EBC). Nevertheless, simple tools such as immunohistochemistry may still be required in particular cases to complement traditional and molecular prognosticators. In this study, the prognostic significance of three well-known immunohistochemical biomarkers, cathepsin D, E-cadherin and Ki67, was studied in 270 patients with EBC, followed by a median time of 126 months in a single institution. Histological examination was performed to confirm the histopathological diagnosis and select specimens. The specimens were evaluated using immunohistochemistry and survival curves were plotted. Results revealed the following patient characteristics: node-negative/1-3 lymph nodes in 228 (86%) patients, hormone receptor-positive in 217 (80%); triple-negative in 31 (11%), and Her2-overexpression in 23 (9%) patients. Breast cancer-related events occurred in 37 patients (14%). A total of 217 patients (80%) survived. Receiver operating characteristic analysis for breast cancer-specific survival showed an area under curve for the clinicopathological model of 0.75 (95% CI, 0.64-0.86), 0.79 (95% CI, 0.68-0.90) for the three-biomarker model, and 0.82 (95% CI, 0.72-0.92) for the E-cadherin and cathepsin D only model. We propose that a simple prognostic model based on combined scores of E-cadherin and cathepsin D may aid treatment decisions in patients with EBC.

A nomogram predicting the probability of primary breast cancer survival at 2- and 5-years using pathological and biological tumor parameters

PURPOSE

Our objective was to develop a nomogram to predict individual overall survival (OS) for primary breast cancer, based on pathological and biological tumor parameters.

METHODS

A retrospective study in a cohort of 180 patients with primary breast cancer was used to build the nomogram. Pathological factors and tumor proteases measured prospectively in primary tumors were used. A multivariate Cox proportional hazards model was used to explore the relationship with OS, and regression coefficients were used to build the nomogram. The nomogram was internally validated with 200 bootstrap re-samples.

RESULTS

The final variables included in the nomogram comprised tumor size (P = 0.04), nodal pathological status (P = 0.01), estrogen receptor status (P = 0.04), urokinase plasminogen activator inhibitor-1 (PAI-1; P = 0.02), thymidine kinase (P = 0.03), and cathepsin D (P = 0.004). The predictive accuracy of the nomogram at estimating the probability of OS, at both 2 and 5 years, was respectively 0.874 and 0.832 before and after calibration.

CONCLUSION

A nomogram to predict 2- and 5-year OS in BC, using histological and biological parameters was successfully developed. This prognostic tool should prove useful in decision-making and therapeutic research.

Emerging roles of cathepsin E in host defense mechanisms

Cathepsin E is an intracellular aspartic proteinase of the pepsin superfamily, which is predominantly expressed in certain cell types, including the immune system cells and rapidly regenerating gastric mucosal and epidermal keratinocytes. The intracellular localization of this protein varies with different cell types. The endosomal localization is primarily found in antigen-presenting cells and gastric cells. The membrane association is observed with certain cell types such as erythrocytes, osteoclasts, gastric parietal cells and renal proximal tubule cells. This enzyme is also found in the endoplasmic reticulum, Golgi complex and cytosolic compartments in various cell types. In addition to its intracellular localization, cathepsin E occurs in the culture medium of activated phagocytes and cancer cells as the catalytically active enzyme. Its strategic expression and localization thus suggests the association of this enzyme with specific biological functions of the individual cell types. Recent genetic and pharmacological studies have particularly suggested that cathepsin E plays an important role in host defense against cancer cells and invading microorganisms. This review focuses emerging roles of cathepsin E in immune system cells and skin keratinocytes, and in host defense against cancer cells. This article is part of a Special Issue entitled: Proteolysis 50 years after the discovery of lysosome.

Diagnostic potential of saliva: current state and future applications

BACKGROUND

Over the past 10 years, the use of saliva as a diagnostic fluid has gained attention and has become a translational research success story. Some of the current nanotechnologies have been demonstrated to have the analytical sensitivity required for the use of saliva as a diagnostic medium to detect and predict disease progression. However, these technologies have not yet been integrated into current clinical practice and work flow.

CONTENT

As a diagnostic fluid, saliva offers advantages over serum because it can be collected noninvasively by individuals with modest training, and it offers a cost-effective approach for the screening of large populations. Gland-specific saliva can also be used for diagnosis of pathology specific to one of the major salivary glands. There is minimal risk of contracting infections during saliva collection, and saliva can be used in clinically challenging situations, such as obtaining samples from children or handicapped or anxious patients, in whom blood sampling could be a difficult act to perform. In this review we highlight the production of and secretion of saliva, the salivary proteome, transportation of biomolecules from blood capillaries to salivary glands, and the diagnostic potential of saliva for use in detection of cardiovascular disease and oral and breast cancers. We also highlight the barriers to application of saliva testing and its advancement in clinical settings.

SUMMARY

Saliva has the potential to become a first-line diagnostic sample of choice owing to the advancements in detection technologies coupled with combinations of biomolecules with clinical relevance.

Cathepsin-D, a key protease in breast cancer, is up-regulated in obese mouse and human adipose tissue, and controls adipogenesis

The aspartic protease cathepsin-D (cath-D) is overexpressed by human epithelial breast cancer cells and is closely correlated with poor prognosis in breast cancer. The adipocyte is one of the most prominent cell types in the tumor-microenvironment of breast cancer, and clinical studies have shown that obesity increases the incidence of breast cancer. Here, we provide the first evidence that cath-D expression is up-regulated in adipose tissue from obese human beings, as well as in adipocytes from the obese C57BI6/J mouse. Cath-D expression is also increased during human and mouse adipocyte differentiation. We show that cath-D silencing in 3T3-F442A murine preadipocytes leads to lipid-depleted cells after adipogenesis induction, and inhibits of the expression of PPARγ, HSL and aP2 adipocyte differentiation markers. Altogether, our findings demonstrate the key role of cath-D in the control of adipogenesis, and suggest that cath-D may be a novel target in obesity.

Clinical significance of the nuclear receptor co-regulator DC-SCRIPT in breast cancer: an independent retrospective validation study

Introduction

In this study we aimed to validate the prognostic value of DC-SCRIPT mRNA expression in a large independent breast cancer cohort. In addition, since DC-SCRIPT is a transcriptional co-regulator of nuclear receptors, we explored its prognostic value in relation to estrogen-receptor-α (ESR1) and -β (ESR2) and evaluated its predictive value for response to tamoxifen treatment.

Methods

DC-SCRIPT mRNA levels were measured by real-time PCR in 1,505 primary invasive breast cancers and associated with outcome (disease-free survival (DFS), metastasis-free survival (MFS) and overall survival (OS)) using univariate and multivariable Cox regression analysis. Logistic and Cox regressions were used to associate DC-SCRIPT levels with clinical benefit and progression-free survival (PFS) for 296 patients treated with first-line systemic tamoxifen for advanced disease.

Results

In univariate and multivariable analysis higher DC-SCRIPT levels were associated with a favorable outcome for both the entire cohort and patients with lymph node-negative (LNN) disease that did not receive adjuvant therapy (DFS, MFS and OS; all, P < 0.001). This association was most pronounced in small (pT1) tumors, in ESR1-positive tumors and in tumors with low ESR2 expression. For first-line endocrine therapy for advanced disease no predictive association was seen with clinical benefit or PFS.

Conclusions

This study provides a higher level of evidence that DC-SCRIPT is indeed an independent, pure prognostic, factor for primary breast cancer and shows that DC-SCRIPT mRNA expression is most informative for either ESR1-positive and/or ESR2-low pT1 tumors.

A systems biology analysis of metastatic melanoma using in-depth three-dimensional protein profiling

Melanoma is an excellent model to study molecular mechanisms of tumor progression because melanoma usually develops through a series of architecturally and phenotypically distinct stages that are progressively more aggressive, culminating in highly metastatic cells. In this study, we used an in-depth, 3-D protein level, comparative proteome analysis of two genetically, very closely related melanoma cell lines with low- and high-metastatic potentials to identify proteins and key pathways involved in tumor progression. This proteome comparison utilized fluorescent tagging of cell lysates followed by microscale solution IEF prefractionation and subsequent analysis of each fraction on narrow-range 2-D gels. LC-MS/MS analysis of gel spots exhibiting significant abundance changes identified 110 unique proteins. The majority of observed abundance changes closely correlate with biological processes central to cancer progression, such as cell death and growth and tumorigenesis. In addition, the vast majority of protein changes mapped to six cellular networks, which included known oncogenes (JNK, c-myc, and N-myc) and tumor suppressor genes (p53 and transforming growth factor-β) as critical components. These six networks showed substantial connectivity, and most of the major biological functions associated with these pathways are involved in tumor progression. These results provide novel insights into cellular pathways implicated in melanoma metastasis.

Advances in proximal fluid proteomics for disease biomarker discovery

Although serum/plasma has been the preferred source for identification of disease biomarkers, these efforts have been met with little success, in large part due the relatively small number of highly abundant proteins that render the reliable detection of low abundant disease-related proteins challenging due to the expansive dynamic range of concentration of proteins in this sample. Proximal fluid, the fluid derived from the extracellular milieu of tissues, contains a large repertoire of shed and secreted proteins that are likely to be present at higher concentrations relative to plasma/serum. It is hypothesized that many, if not all, proximal fluid proteins exchange with peripheral circulation, which has provided significant motivation for utilizing proximal fluids as a primary sample source for protein biomarker discovery. The present review highlights recent advances in proximal fluid proteomics, including the various protocols utilized to harvest proximal fluids along with detailing the results from mass spectrometry- and antibody-based analyses.

Procathepsin D and cancer: From molecular biology to clinical applications

Procathepsin D (pCD) is overexpressed and secreted by cells of various tumor types including breast and lung carcinomas. pCD affects multiple features of tumor cells including proliferation, invasion, metastases and apoptosis. Several laboratories have previously shown that the mitogenic effect of pCD on cancer cells is mediated via its propeptide part (APpCD). However, the exact mechanism of how pCD affects cancer cells has not been identified. Recent observations have also revealed the possible use of pCD/APpcD as a marker of cancer progression. The purpose of this review is to summarize the three major potentials of pCD-tumor marker, potential drug, and screening agent.

Cathepsin D messenger RNA is downregulated in human lung cancer

OBJECTIVES

Lysosomal proteases cathepsins B and D (CB and CD) play a significant part in cancer progression. For many oncological diseases protein expression levels of CB and CD have been investigated and correlations with tumour characteristics revealed. Meanwhile, there is very little information concerning mRNA expression level.

METHODS

In the present work, data about mRNA levels of CB and CD in human lung cancer was obtained using reverse transcription followed by real-time polymerase chain reaction.

RESULTS

For the first time CD and CB mRNA in human lung cancer tumours was quantified. It was shown that CB and CD mRNA levels do not correlate with any tumour characteristics. However, in most analysed tumours, expression of CD mRNA was downregulated compared with adjacent normal tissue (p <0.0003).

CONCLUSIONS

The data obtained indicate CD mRNA as a potential lung cancer marker.

Prospective Evaluation of Carcinoembryonic Antigen (CEA) and Carbohydrate Antigen 15.3 (CA 15.3) in Patients with Primary Locoregional Breast Cancer

Background: The utility of carcinoembryonic antigen (CEA) and carbohydrate antigen 15.3 (CA 15.3) as prognostic factors in primary breast cancer is unclear.

Methods: We prospectively studied CEA and CA 15.3 in the sera of 2062 patients with untreated primary breast cancer diagnosed between 1984 and 2008.

Results: Increased CEA (&gt;5 μg/L) and CA 15.3 (&gt;30 kU/L) concentrations were found in 12.7% and 19.6% of the patients, respectively, and 1 or both tumor markers were increased in 28% (570 of 2062). Increases in each tumor marker correlated with larger tumor sizes and nodal involvement. Tumor size, estrogen receptor (ER), and CEA were independent prognostic factors by multivariate analysis in the total group [disease free survival (DFS) and overall survival (OS)] as well as in node-positive (NP) and node-negative (NN) patients. Nodal involvement and histological grade were independent prognostic factors in the total group as well as in NP patients. By contrast, adjuvant treatment and CA 15.3 were independent prognostic factors only in NN patients (DFS and OS). All patients with CEA &gt;7.5 μg/L had recurrence during follow-up. Use of both tumor markers allowed discrimination of the groups of risk in T1 NN patients: 56.3% of recurrences were seen when 1 or both tumor markers were increased, whereas only 9.4% of recurrences were seen in T1 NN patients without increases of either marker.

Conclusions: CEA and CA 15.3 are useful prognostic factors in NP and NN breast cancer patients. CEA &gt;7.5 μg/L is associated with a high probability of subclinical metastases.

Nipple Aspirate Fluid Proteome of Healthy Females and Patients with Breast Cancer

Background: The ductal/alveolar system of the female breast constantly secretes and reabsorbs fluid in nonpregnant/nonlactating women. This fluid, referred to as nipple aspirate fluid (NAF), can be obtained by a noninvasive procedure and it is part of the microenvironment where more than 95% of breast cancers arise.

Methods: Using an Orbitrap® mass analyzer coupled to a linear ion trap, we performed an in-depth proteomic analysis of NAF samples obtained from 3 healthy individuals and 3 patients with breast cancer. Multiple fractionation methods such as size-exclusion and anion-exchange chromatography were applied for protein separation before mass spectrometric analysis.

Results: We identified more than 800 unique proteins in total, generating the most extensive NAF proteome thus far. Using gene ontology, we classified the identified proteins by their subcellular localization and found that more than 50% were extracellular or plasma membrane proteins. By searching against the Plasma Proteome Database, we confirmed that 40% of the proteins were also found in the plasma. Unigene database searching for transcripts of the proteins not found in the plasma revealed that the vast majority were expressed in the mammary gland.

Conclusions: Our extensive proteome database for NAF may be helpful in the identification of novel cancer biomarkers.

Anti-p53 antibodies in serum: relationship to tumor biology and prognosis of breast cancer patients

The aim of this study was to analyze the concentration of anti-p53 antibodies in the serum of breast cancer patients and to correlate these results with various clinical, pathological and biochemical parameters. We also wanted to assess the prognostic significance of these antibodies in our patients. Sera from 61 patients with breast cancer and 20 individuals without malignancies were analyzed using enzyme-linked immunoadsorbent assay. High levels of anti-p53 antibodies were detected in twenty-one (35%) breast cancer patients and one control (5%). The difference was statistically significant. We observed an inverse relationship between the anti-p53 antibodies and the age of the patients. We found significant association of anti-p53 antibodies with tumor size, histological grade of the tumors and the number of axillary lymph nodes involved. The levels of anti-p53 antibodies were higher in patients with negative estrogen and progesterone receptors in comparison with patients with positive steroid receptors, but the difference was not statistically significant. No relation was observed between anti-p53 antibodies neither with the Cathepsin D levels in the cytosol nor with the HER-2/neu extracellular domain in the serum. Patients with primary tumors and higher levels of anti-p53 antibodies had shorter 5-year survival than patients with lower levels of anti-p53 antibodies. Our results support the role of anti-p53 antibodies as a biomarker of less favorable phenotype as well as a prognostic factor for patients with breast cancer.

Tumor tissue levels of Tissue Inhibitor of Metalloproteinases-1 (TIMP-1) and outcome following adjuvant chemotherapy in premenopausal lymph node-positive breast cancer patients: A retrospective study

Background

We have previously demonstrated that high tumor tissue levels of TIMP-1 are associated with no or limited clinical benefit from chemotherapy with CMF and anthracyclines in metastatic breast cancer patients. Here, we extend our investigations to the adjuvant setting studying outcome after adjuvant chemotherapy in premenopausal lymph node-positive patients. We hypothesize that TIMP-1 high tumors are less sensitive to chemotherapy and accordingly that high tumor tissue levels are associated with shorter survival.

Methods

From our original retrospectively collected tumor samples we selected a group of 525 pre-menopausal lymph node-positive patients (adjuvant treatment: CMF, 324 patients; anthracycline-based, 99 patients; no adjuvant chemotherapy, 102 patients). TIMP-1 levels were measured using ELISA in cytosolic extracts of frozen primary tumors. TIMP-1 was analyzed as a continuous variable and as a dichotomized one using the median TIMP-1 concentration as a cut point between high and low TIMP-1 groups. We analyzed the benefit of adjuvant CMF and anthracyclines in univariate and multivariable survival models; endpoints were disease-free (DFS) and overall survival (OS).

Results

In this selected cohort of high-risk patients, and in the subgroup of patients receiving no adjuvant therapy, TIMP-1 was not associated with prognosis. In the subgroup of patients treated with anthracyclines, when analyzed as a continuous variable we observed a tendency for increasing TIMP-1 levels to be associated with shorter DFS (multivariable analysis, HR 1.75, 95% CI 1.00-3.07, P = 0.05) and a significant association between increasing TIMP-1 and shorter OS in both univariate (HR 3.52, 95% CI 1.54-8.06, P = 0.003) and multivariable analyses (HR 4.19, 95% CI 1.67-10.51, P = 0.002). No statistically significant association between TIMP-1 and DFS was observed in the CMF-treated patients although high TIMP-1 was associated with shorter OS when analyzed as a dichotomized variable (HR 1.64, 95% CI 1.02-2.65, P = 0.04).

Conclusion

In the subgroup of patients receiving adjuvant chemotherapy we found an association between shorter survival after treatment in TIMP-1 high patients compared with TIMP-1 low patients, especially in patients receiving anthracycline-based therapy. This suggests that high tumor tissue levels of TIMP-1 might be associated with reduced benefit from classical adjuvant chemotherapy. Our findings should be validated in larger prospective studies.

National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines for Use of Tumor Markers in Testicular, Prostate, Colorectal, Breast, and Ovarian Cancers

Background: Updated National Academy of Clinical Biochemistry (NACB) Laboratory Medicine Practice Guidelines for the use of tumor markers in the clinic have been developed.

Methods: Published reports relevant to use of tumor markers for 5 cancer sites—testicular, prostate, colorectal, breast, and ovarian—were critically reviewed.

Results: For testicular cancer, α-fetoprotein, human chorionic gonadotropin, and lactate dehydrogenase are recommended for diagnosis/case finding, staging, prognosis determination, recurrence detection, and therapy monitoring. α-Fetoprotein is also recommended for differential diagnosis of nonseminomatous and seminomatous germ cell tumors. Prostate-specific antigen (PSA) is not recommended for prostate cancer screening, but may be used for detecting disease recurrence and monitoring therapy. Free PSA measurement data are useful for distinguishing malignant from benign prostatic disease when total PSA is &lt;10 μg/L. In colorectal cancer, carcinoembryonic antigen is recommended (with some caveats) for prognosis determination, postoperative surveillance, and therapy monitoring in advanced disease. Fecal occult blood testing may be used for screening asymptomatic adults 50 years or older. For breast cancer, estrogen and progesterone receptors are mandatory for predicting response to hormone therapy, human epidermal growth factor receptor-2 measurement is mandatory for predicting response to trastuzumab, and urokinase plasminogen activator/plasminogen activator inhibitor 1 may be used for determining prognosis in lymph node–negative patients. CA15-3/BR27–29 or carcinoembryonic antigen may be used for therapy monitoring in advanced disease. CA125 is recommended (with transvaginal ultrasound) for early detection of ovarian cancer in women at high risk for this disease. CA125 is also recommended for differential diagnosis of suspicious pelvic masses in postmenopausal women, as well as for detection of recurrence, monitoring of therapy, and determination of prognosis in women with ovarian cancer.

Conclusions: Implementation of these recommendations should encourage optimal use of tumor markers.

Cathepsin D--many functions of one aspartic protease

For years, it has been held that cathepsin D (CD) is involved in rather non-specific protein degradation in a strongly acidic milieu of lysosomes. Studies with CD knock-out mice revealed that CD is not necessary for embryonal development, but it is indispensable for postnatal tissue homeostasis. Mutation that abolishes CD enzymatic activity causes neuronal ceroid lipofuscinosis (NCL) characterized by severe neurodegeneration, developmental regression, visual loss and epilepsy in both animals and humans. In the last decade, however, an increasing number of studies demonstrated that enzymatic function of CD is not restricted solely to acidic milieu of lysosomes with important consequences in regulation of apoptosis. In addition to CD enzymatic activity, it has been shown that apoptosis is also regulated by catalytically inactive mutants of CD which suggests that CD interacts with other important molecules and influences cell signaling. Moreover, procathepsin D (pCD), secreted from cancer cells, acts as a mitogen on both cancer and stromal cells and stimulates their pro-invasive and pro-metastatic properties. Numerous studies found that pCD/CD level represents an independent prognostic factor in a variety of cancers and is therefore considered to be a potential target of anti-cancer therapy. Studies dealing with functions of cathepsin D are complicated by the fact that there are several simultaneous forms of CD in a cell-pCD, intermediate enzymatically active CD and mature heavy and light chain CD. It became evident that these forms may differently regulate the above-mentioned processes. In this article, we review the possible functions of CD and its various forms in cells and organisms during physiological and pathological conditions.

Estrogen-regulated cut-off values of pS2 and cathepsin D expression in breast carcinomas

The purpose of the study was to asses the expression of estrogen-induced pS2 and cathepsin D (CD) that might facilitate biological subgrouping of patients with breast carcinomas (BC) and its potential applicability in clinical oncology. The study included 226 patients with histologically verified BC. Clinico-pathological findings were classified according to age, menopausal status, tumor size, histologic grade, and regional lymph node status. Estrogen and progesterone receptors (ER and PR), as well as CD and pS2 protein concentrations were assayed on the same cytosolic extract in accordance with the recommendation of EORTC. Statistically significant direct correlations were observed between CD expression and axillary node status and between pS2 expression and histologic grade, while the expression of both proteins was related to both ER and PR status. Baseline levels of CD expression were found in patients with SR-negative status and node-negative or tumors less than 2cm. Unfavorable carcinoma subgroups, in relation to pS2 expression, were defined as pre- and postmenopausal carcinomas with histologic grade III. The highest CD level observed in SR-negative unfavorable subgroups (38.7 pmol/mg) and the highest pS2 level observed in ER(-) unfavorable subgroups (14.7 ng/mg) were considered as the cut-off values. These values defined estrogen-regulated expression of CD and pS2 protein that might enable the identification of patients at high risk of disease progression, for whom more aggressive adjuvant approach would be warranted, as well as the identification of patients whose prognosis is so good that adjuvant therapy would not be cost-beneficial.

Thrombin up-regulates cathepsin D which enhances angiogenesis, growth, and metastasis

Cathepsin D (CD) up-regulation has been associated with human malignancy and poor prognosis. Thrombin up-regulated CD mRNA and protein in eight tumor cell lines as well as in human umbilical vascular endothelial cells (HUVEC). Thrombin increased the secretion of CD by 3- to 8-fold and enhanced chemotaxis ( approximately 2-fold) in 4T1 murine mammary CA cells, which was completely inhibited with the knockdown of CD. Secreted 4T1 CD induced neoangiogenesis by 2.4-fold on a chick chorioallantoic membrane, which was blocked in CD-KD cells. The addition of pure CD (2 ng) to the chick chorioallantoic membrane increased angiogenesis by 2.1-fold, which was completely inhibited by Pepstatin A (Pep A). CD enhanced human HUVEC chemotaxis and Matrigel tube formation by 2-fold, which was then blocked by Pep A. CD enhanced HUVEC matrix metalloproteinase 9 (MMP-9) activity by approximately 2-fold, which was completely inhibited by Pep A as well as a generic MMP inhibitor, GM6001. The injection of CD-KD 4T1 cells into syngeneic mice inhibited tumor growth by 3- to 4-fold compared with empty vector (EV) cells. Hirudin, a specific thrombin inhibitor, inhibited the growth of wild-type and EV cells by 2- to 3-fold, compatible with thrombin up-regulation of CD. CD and thrombin also contributed to spontaneous pulmonary metastasis; 4-fold nodule inhibition with CD versus EV and 4.6-fold inhibition with hirudin versus EV (P < 0.02). Thus, thrombin-induced CD contributes to the malignant phenotype by inducing tumor cell migration, nodule growth, metastasis, and angiogenesis. CD-induced angiogenesis requires the proteolytic activation of MMP-9.

The aspartic protease napsin A suppresses tumor growth independent of its catalytic activity

Members of the aspartic protease family have been implicated in cancer progression. The aspartic protease napsin A is expressed in type II cells of the lung, where it is involved in the processing of surfactant protein B (SP-B). Napsin A is also expressed in kidney, where its function is unknown. Here, we examined napsin A mRNA expression in human kidney tissues using in situ hybridization. Whereas strong napsin A mRNA expression was observed in kidney proximal tubules, expression was detected in only one of 29 renal cell carcinomas. This result is consistent with previous observations of loss of napsin A expression in high-grade lung adenocarcinomas. We re-expressed napsin A in the tumorigenic HEK293 kidney cell line and examined the phenotype of stably transfected cells. Napsin A-expressing HEK293 cells showed an altered phenotype characterized by formation of cyst-like structures in three-dimensional collagen cultures. Napsin A-expressing cells also showed reduced capacity for anchorage-independent growth and formed tumors in SCID mice with a lower efficiency and slower onset compared to vector-transfected control cells. Mutation of one of the aspartic acid residues in the napsin A catalytic site inactivated enzymatic activity, but did not influence the ability to suppress colony formation in soft agar and tumor formation. The mutation of the catalytic site did not affect processing, glycosylation or intracellular localization of napsin A. These data show that napsin A inhibits tumor growth of HEK293 cells by a mechanism independent of its catalytic activity.

American Society of Clinical Oncology 2007 update of recommendations for the use of tumor markers in breast cancer

PURPOSE

To update the recommendations for the use of tumor marker tests in the prevention, screening, treatment, and surveillance of breast cancer.

METHODS

For the 2007 update, an Update Committee composed of members from the full Panel was formed to complete the review and analysis of data published since 1999. Computerized literature searches of MEDLINE and the Cochrane Collaboration Library were performed. The Update Committee's literature review focused attention on available systematic reviews and meta-analyses of published tumor marker studies. In general, significant health outcomes (overall survival, disease-free survival, quality of life, lesser toxicity, and cost-effectiveness) were used for making recommendations. Recommendations and

CONCLUSIONS

Thirteen categories of breast tumor markers were considered, six of which were new for the guideline. The following categories showed evidence of clinical utility and were recommended for use in practice: CA 15-3, CA 27.29, carcinoembryonic antigen, estrogen receptor, progesterone receptor, human epidermal growth factor receptor 2, urokinase plasminogen activator, plasminogen activator inhibitor 1, and certain multiparameter gene expression assays. Not all applications for these markers were supported, however. The following categories demonstrated insufficient evidence to support routine use in clinical practice: DNA/ploidy by flow cytometry, p53, cathepsin D, cyclin E, proteomics, certain multiparameter assays, detection of bone marrow micrometastases, and circulating tumor cells.

Dissecting the molecular mechanisms of cancer through bioinformatics-based experimental approaches

Cancer is a disease of aberrant gene expression characterized by inappropriate (temporal or quantitative) expression of positive mediators of cell proliferation in conjunction with diminished expression of negative mediators of cell growth. Alteration of the normal balance of these positive and negative mediators leads to the abnormal growth of cells and tissues that typify neoplastic disease. Development of a better understanding of the genetic and epigenetic mechanisms that induce neoplastic transformation and drive the cancer phenotype is essential for continued progress towards the design of practical molecular diagnostics and effective treatment strategies. Over the past decades, molecular techniques that facilitate the assessment of gene expression, identification of gene mutations, and characterization of chromosome abnormalities (numeric and structural) have been established and applied to cancer research. However, many of these techniques are slow and labor-intensive. More recently, high-throughput technologies have emerged that generate large volumes of data related to the genetics and epigenetics of cancer (or other disorders). These advances in molecular genetic technology required the development of sophisticated bioinformatic tools to manage the large datasets generated. The combination of high-throughput molecular assays and bioinformatic-based data mining strategies has significantly impacted our understanding of the molecular pathogenesis of cancer, classification of tumors, and now the management of cancer patients in the clinic. This article will review basic molecular techniques and bioinformatic-based experimental approaches used to dissect the molecular mechanisms of carcinogenesis.

Differential expression of proteins during the canceration of colorectal adenoma cells

Colorectal carcinoma is one of the most frequently seen malignant tumors of the gastric tract. Colorectal adenomas are considered to be precancerous lesions of colorectal carcinoma. The adenoma-carcinoma sequence has traditionally been characterized as a uniform progression from normal mucosa to adenoma to carcinoma through an underlying homogenous carcinogenic pathway. Current research indicates that some proteins are differentially expressed in colorectal adenomas during their carcinomatous changes. These proteins include cell skeleton-related proteins, intracellular enzymes and proteins involved in cellular signal transduction. The functional roles of these proteins in the carcinomatous changes of colorectal adenomas differ greatly from each other and have not yet been fully clarified. This article reviews these differentially expressed proteins and briefly describes the possible mechanism by which these proteins cause the malignant transition from colorectal adenoma to colorectal carcinoma. Furthermore, proteomic technology has developed rapidly and has been simultaneously applied to the detection and characterization of various kinds of proteins due to its high throughput and convenient nature. This article also introduces the utilization of proteomics to identify and compare proteins that are differentially expressed between colorectal adenoma and colorectal carcinoma. Research on these proteins may lead to the identification of cancer markers that could subsequently facilitate the early diagnosis and further understanding of colorectal carcinoma.

Deciphering the molecular basis of breast cancer metastasis with mouse models

Breast cancer begins as a localized disease, but has the potential to spread to distant sites within the body. This process--known as metastasis--is the leading cause of death from breast cancer. Whether the ability of cancer cells to metastasize is an intrinsic or acquired feature is currently a topic of considerable debate. Nevertheless, the key cellular events required for metastasis are generally accepted. These include invasion of the surrounding stromal tissue, intravasation, evasion of programmed cell death, arrest within the vasculature at a distant site, extravasation, and establishment and growth within a new microenvironment. The development of mouse models that faithfully mimic critical aspects of human neoplasia has been instrumental in framing our current understanding of multistage carcinogenesis. This review examines the advantages and limitations of existing murine models for mammary carcinogenesis for probing the molecular mechanisms that contribute to metastasis, as well as non-invasive tumor imaging approaches to facilitate these investigations.

Procathepsin D expression correlates with invasive and metastatic phenotype of MDA-MB-231 derived cell lines

Procathepsin D (pCD) is a glycoprotein secreted abundantly by cancerous cells with a documented role in tumor development. The levels of pCD in primary tumors are highly correlated with an increased incidence of metastasis. Our earlier studies have shown that pCD exerts its effect on cancer cells through its activation peptide (AP) and involves both autocrine and paracrine modes of action. In this study, we analyzed the expression and role of pCD in MDA-MB-231 and its derived cell lines 1833 and 4175 possessing discrete metastatic abilities. Our results demonstrated a direct relationship between expression and secretion of pCD to the differential invasive potential of these cells. Also, the cell lines responded to AP treatment by enhancing their invasive potential, proliferation and induction of secretion of various cytokines, suggesting that pCD plays a role in metastasis through its AP region.

Primary tumor levels of tissue inhibitor of metalloproteinases-1 are predictive of resistance to chemotherapy in patients with metastatic breast cancer

PURPOSE

Only about 50% of metastatic breast cancer patients benefit from cytotoxic chemotherapy. Today, no validated markers exist for prediction of chemotherapy sensitivity/resistance in this patient group. Tissue inhibitor of metalloproteinases-1 (TIMP-1) has been shown to protect against apoptosis, and the purpose of the present study was to test the hypothesis that tumors expressing high levels of TIMP-1 are protected against apoptosis-inducing agents and thus less sensitive to apoptosis-inducing chemotherapeutic drugs.

EXPERIMENTAL DESIGN

We investigated the association between primary tumor expression levels of TIMP-1 protein and objective response to first-line chemotherapy in 173 patients with metastatic breast cancer.

RESULTS

When analyzed as a continuous log-transformed variable, increasing TIMP-1 levels were significantly associated with lack of response to cyclophosphamide/methotrexate/5-fluorouracil and anthracycline-based chemotherapy (P = 0.01; odds ratio, 2.0; 95% confidence interval, 1.1-3.3). In a multivariate model, including lymph node status, steroid hormone receptor status, menopausal status, dominant metastases site, type of chemotherapy, and disease-free interval, TIMP-1 was significantly associated with resistance to treatment (P = 0.03; odds ratio, 1.7; 95% confidence interval, 1.1-3.3).

CONCLUSIONS

In the present exploratory study, we showed that elevated tumor tissue TIMP-1 levels were significantly associated with a poor response to chemotherapy. By using TIMP-1, we identified a group of patients with metastatic breast cancer, which hardly respond to the most frequently used chemotherapy regimes (i.e., cyclophosphamide/methotrexate/5-fluorouracil and anthracyclines).

Proteomic analysis of MCF-7 cell lines expressing the zinc-finger or the proline-rich domain of retinoblastoma-interacting-zinc-finger protein

To identify a growth-promoting activity related to retinoblastoma-interacting-zinc-finger (RIZ) protein, differential protein expression of MCF-7 cell lines expressing the zinc-finger or the proline-rich domain of RIZ protein was analyzed by a robust bottom-up mass-spectrometry proteomic approach. Spots corresponding to qualitative and quantitative differences in protein expression have been selected and identified. Some of these proteins have been previously reported as being associated with different types of carcinomas or involved in cell proliferation and differentiation. Knowledge of specific differentially expressed proteins by MCF-7-derived cell lines expressing RIZ different domains will provide the basis for identifying a growth-promoting activity related to RIZ gene products.

Overexpression of both catalytically active and -inactive cathepsin D by cancer cells enhances apoptosis-dependent chemo-sensitivity

The aspartic protease cathepsin D (cath-D) is a key mediator of induced-apoptosis and its proteolytic activity has been generally involved in this event. During apoptosis, cath-D is translocated to the cytosol. Because cath-D is one of the lysosomal enzymes that requires a more acidic pH to be proteolytically active relative to the cysteine lysosomal enzymes such as cath-B and -L, it is therefore open to question whether cytosolic cath-D might be able to cleave substrate(s) implicated in the apoptotic cascade. Here, we have investigated the role of wild-type cath-D and its proteolytically inactive counterpart overexpressed by 3Y1-Ad12 cancer cells during chemotherapeutic-induced cytotoxicity and apoptosis, as well as the relevance of cath-D catalytic function. We demonstrate that wild-type or mutated catalytically inactive cath-D strongly enhances chemo-sensitivity and apoptotic response to etoposide. Both wild-type and mutated inactive cath-D are translocated to the cytosol, increasing the release of cytochrome c, the activation of caspases-9 and -3 and the induction of a caspase-dependent apoptosis. In addition, pretreatment of cells with the aspartic protease inhibitor, pepstatin A, does not prevent apoptosis. Interestingly therefore, the stimulatory effect of cath-D on cell death is independent of its catalytic activity. Overall, our results imply that cytosolic cath-D stimulates apoptotic pathways by interacting with a member of the apoptotic machinery rather than by cleaving specific substrate(s).

Cathepsin D: newly discovered functions of a long-standing aspartic protease in cancer and apoptosis

The lysosomal aspartic protease cathepsin D (cath-D) is over-expressed and hyper-secreted by epithelial breast cancer cells. This protease is an independent marker of poor prognosis in breast cancer being correlated with the incidence of clinical metastasis. Cath-D over-expression stimulates tumorigenicity and metastasis. Indeed it plays an essential role in the multiple steps of tumor progression, in stimulating cancer cell proliferation, fibroblast outgrowth and angiogenesis, as well as in inhibiting tumor apoptosis. A mutated cath-D devoid of catalytic activity still proved mitogenic for cancer, endothelial and fibroblastic cells, suggesting an extra-cellular mode of action of cath-D involving a triggering, either directly or indirectly, of an as yet unidentified cell surface receptor. Cath-D is also a key mediator of induced-apoptosis and its proteolytic activity has been involved generally in this event. During apoptosis, mature lysosomal cath-D is translocated to the cytosol. Since cath-D is one of the lysosomal enzymes which requires a more acidic pH to be proteolytically-active relative to the cysteine lysosomal enzymes, such as cath-B and -L, it is open to question whether cytosolic cath-D might be able to cleave substrate(s) implicated in the apoptotic cascade. This review summarises our current knowledge on cath-D action in cancer progression and metastasis, as well as its dual function in apoptosis.

DUAL ROLE OF CATHEPSIN D: LIGAND AND PROTEASE

Cathepsin D is peptidase belonging to the family of aspartic peptidases. Its mostly described function is intracellular catabolism in lysosomal compartments, other physiological effect include hormone and antigen processing. For almost two decades, there have been an increasing number of data describing additional roles imparted by cathepsin D and its pro-enzyme, resulting in cathepsin D being a specific biomarker of some diseases. These roles in pathological conditions, namely elevated levels in certain tumor tissues, seem to be connected to another, yet not fully understood functionality. However, despite numerous studies, the mechanisms of cathepsin D and its precursor's actions are still not completely understood. From results discussed in this article it might be concluded that cathepsin D in its zymogen status has additional function, which is rather dependent on a "ligand-like" function then on proteolytic activity.

Cathepsin D is a potential serum marker for poor prognosis in glioma patients

Cathepsin D is an aspartyl protease involved in protein catabolism and tissue remodeling which can be secreted from cancer cells. To identify a potential serum marker for gliomas, we investigated the gene expression levels of cathepsin D in 87 tissue samples and measured the protein concentrations in sera of glioma patients. The tissue samples consisted of 43 glioblastomas, 13 anaplastic astrocytomas, 22 astrocytomas, and 9 normal brain tissues. The results of real-time quantitative reverse transcription-PCR analysis showed that cathepsin D transcript levels became significantly higher as the glioma grade advanced (P = 0.0466, glioblastoma and anaplastic astrocytoma; P = 0.0008, glioblastoma and astrocytoma; P = 0.0271, glioblastoma and normal brain tissue; unpaired t test). Immunohistochemical analysis with anti-cathepsin D antibody revealed dense and spotty staining in the tumor cells with high transcript levels. The low expression of cathepsin D significantly correlated with long survival of the glioma patients. Furthermore, the glioblastoma patients with high gene expression of cathepsin D lived significantly shorter than those with low expression (P = 0.0104, Cox-Mantel log-rank test) and frequently had leptomeningeal dissemination (P = 0.0016, chi2 test). The multivariate analysis confirmed that the cathepsin D expression level was an independent predictor for short survival (P = 0.0102, Cox proportional hazard regression model). Measurement of the serum cathepsin D concentrations by ELISA showed a significant increase in the patients with high-grade gliomas as compared with the low-grade tumors (P = 0.0081, chi2 test). These results collectively suggest that cathepsin D could be a potential serum marker for the prediction of aggressive nature of human gliomas.

Cathepsin D-related Disease-free Interval in pT1 Primary Breast Carcinomas: A Pilot Study

In order to address the heterogeneity of the pT1 breast cancer stages, we have been examining the natural and the clinical course of disease in relation to cathepsin D expression, as a molecular marker for the tumor progression that leads to metastasis. The original aim of our pilot study was to determine whether it was possible to distinguish high-risk from low-risk patients, on the basis of nonestrogen- vs. estrogen-regulated cathepsin D expression. Our results showed that estrogen-regulated cathepsin D expression could be useful as surrogate marker of node-positive status. Further, during the natural course of disease, none of 7 pT1N0 patients with tumors bearing nonestrogen-regulated cathepsin D expression developed metastasis. During the clinical course of disease, nonestrogen-regulated cathepsin D expression defined low-risk while estrogen-regulated cathepsin D expression defined high-risk pT1N+ subgroup of patients. Although there is no consensus with respect to metastasis-related prognostic value of cathepsin D expression, our pilot study implies its prognostic value in pT1 breast cancer patients and supports the hypothesis that cathepsin D may promote metastasis in this early stage of disease.

Involvement of cathepsins in the invasion, metastasis and proliferation of cancer cells

Tumor cell invasion and metastasis are associated with the proteolytic activity of various types of proteinases. Among them, cathepsins, which are lysosomal proteinases, have received more attention recently. Since elevated expressions of cathepsins and diminished levels of their inhibitors have been observed in several human cancers, including breast, gastric and prostate cancer, especially in aggressive cancer cells, cathepsins have been suggested to be biological markers of malignant tumors and have proved useful for prognosis of the disease. Furthermore, cathepsins have various roles in cancer progression. Cathepsin D has a mitogenic activity independent of its proteolytic activity and it attenuates the anti-tumor immune response of decaying chemokines to inhibit the function of dendritic cells. Cathepsins B and L have been shown to play an important role in matrix degradation and cell invasion. The administration of their inhibitors prevents the invasion and metastasis of cancer cells. These results indicate that cancer cells orchestrate various cathepsins to progress malignant diseases. Cathepsins may be a potential target for cancer therapy.

Three-dimensional chitosan scaffold-based MCF-7 cell culture for the determination of the cytotoxicity of tamoxifen

Three-dimensional (3D) culture of cancer cell lines has long been advocated as a better model of the malignant phenotype that is most closely related to tumorigenicity in vivo. Moreover, new drug development requires simple in vitro models that resemble the in vivo situation more in order to select active drugs against solid tumours and to decrease the use of experimental animals. A biodegradable, biocompatible and non-toxic polymer chitosan was employed for 3D culture of MCF-7 cell lines. Cells grown on chitosan scaffold produce more lactate from glucose in comparison to that secreted by cells grown on tissue culture plate, thus indicating the suitability of chitosan scaffold as an in vitro model resembling cancer tissue growth in vivo. Cytotoxic effect of tamoxifen at different concentrations was evaluated for MCF-7 breast cancer cell lines grown on tissue culture plate as well as on 3D chitosan scaffold. At a tamoxifen concentration of 10(-6) M, 50% reduction in cell growth was observed in tissue culture plate-grown cells where 15% reduction in cell growth was observed when cells were grown in chitosan scaffold. Higher tamoxifen concentrations were required to achieve comparable cytostatic action in 3D culture, supporting the fact that 3D culture is a better model for the cytotoxic evaluation of anticancer drugs in vitro. Carbohydrate metabolism of MCF-7 cells in terms of glucose utilization and lactate production in 3D and monolayer culture were unaffected by tamoxifen treatment. Cathepsin D activity, an autocrine growth factor in breast cancer cells was monitored in all experiments. In 3D culture, addition of tamoxifen promoted cathepsin D secretion but inhibited its uptake by cells. Growth of cells in 3D chitosan scaffold indicated that action of tamoxifen on estrogen positive cancer cells is also mediated through inhibition of cathepsin D uptake from the culture medium.

Yeast two-hybrid identification of prostatic proteins interacting with human sex hormone-binding globulin

Yeast two-hybrid (Y2H) screening of a prostate cDNA library with the cDNA for sex hormone-binding globulin (SHBG) has been used to identify proteins through which SHBG may exert autocrine or paracrine effects on sex steroid target tissues. The library screen gave 230 positive interactions of which around 60 have been sequenced. Of the proteins identified to date from database (BLAST) searches of these sequences, SHBG is one of those occurring most frequently. Amongst the proteins of interest are the membrane-associated proteins flotillin-1 and PRV-1, the enzymes cathepsin D, kallikrein 4 and acid phosphatase, various metallothioneins and translation elongation factor 1 alpha. The significance of the interaction of SHBG with these proteins is discussed.

Catalytically inactive human cathepsin D triggers fibroblast invasive growth

The aspartyl-protease cathepsin D (cath-D) is overexpressed and hypersecreted by epithelial breast cancer cells and stimulates their proliferation. As tumor epithelial-fibroblast cell interactions are important events in cancer progression, we investigated whether cath-D overexpression affects also fibroblast behavior. We demonstrate a requirement of cath-D for fibroblast invasive growth using a three-dimensional (3D) coculture assay with cancer cells secreting or not pro-cath-D. Ectopic expression of cath-D in cath-D-deficient fibroblasts stimulates 3D outgrowth that is associated with a significant increase in fibroblast proliferation, survival, motility, and invasive capacity, accompanied by activation of the ras-MAPK pathway. Interestingly, all these stimulatory effects on fibroblasts are independent of cath-D proteolytic activity. Finally, we show that pro-cath-D secreted by cancer cells is captured by fibroblasts and partially mimics effects of transfected cath-D. We conclude that cath-D is crucial for fibroblast invasive outgrowth and could act as a key paracrine communicator between cancer and stromal cells, independently of its catalytic activity.

Prognostic significance of matrix metalloproteinase-2, cathepsin D, and tenascin-C expression in colorectal carcinoma

Matrix metalloproteinase-2 (MMP-2) and cathepsin D (CD) play a significant role in degrading the components of basement membrane and extracellular matrix (ECM), whereas tenascin-C (TN-C) is a glycoprotein of the ECM related to cell adhesion and detachment. These proteins have been implicated in tumor invasion and metastasis. Therefore, we aimed at investigating the prognostic significance of MMP-2, CD, and TN-C expressions in primary colorectal cancer. Overall, 112 colorectal adenocarcinomas were included in the present study. MMP-2, CD, and TN-C expressions were evaluated by immunohistochemistry and correlated with clinicopathologic prognostic parameters and survival. Diffuse stromal TN-C immunostaining was found to be significantly correlated with advanced stage and shorter survival time (p = 0.002 and 0.02, respectively). MMP-2 expression was found to correlate with lymph vessel invasion (p = 0.006) and stage (p = 0.03). CD expression was related to depth of invasion (p = 0.005). No significant relationship was found between survival and MMP-2 and CD expression (p > 0.05). In multivariate analysis, stage and vascular invasion were independent prognostic factors, whereas TN-C did not retain a clear independent relationship to survival (p > 0.05). Our findings suggest that TN-C expression may be a potential prognostic marker in colorectal carcinoma. However, MMP-2 and CD do not appear to be significant indicators of survival.

The potentials of MS-based subproteomic approaches in medical science: the case of lysosomes and breast cancer

Because of the great number of women who are diagnosed with breast cancer each year, and though this disease presents the lowest mortality rate among cancers, breast cancer remains a major public health problem. As for any cancer, the tumorigenic and metastatic processes are still hardly understood, and the biochemical markers that allow either a precise monitoring of the disease or the classification of the numerous forms of breast cancer remain too scarce. Therefore, great hopes are put on the development of high-throughput genomic and proteomic technologies. Such comprehensive techniques should help in understanding the processes and in defining steps of the disease by depicting specific genes or protein profiles. Because techniques dedicated to the current proteomic challenges are continuously improving, the probability of the discovery of new potential protein biomarkers is rapidly increasing. In addition, the identification of such markers should be eased by lowering the sample complexity; e.g., by sample fractionation, either according to specific physico-chemical properties of the proteins, or by focusing on definite subcellular compartments. In particular, proteins of the lysosomal compartment have been shown to be prone to alterations in their localization, expression, or post-translational modifications (PTMs) during the cancer process. Some of them, such as the aspartic protease cathepsin D (CatD), have even been proven as participating actively in the disease progression. The present review aims at giving an overview of the implication of the lysosome in breast cancer, and at showing how subproteomics and the constantly refining MS-based proteomic techniques may help in making breast cancer research progress, and thus, hopefully, in improving disease treatment.

Tenascin C and cathepsin d expression in adipocytic tumors: an immunohistochemical investigation of 43 cases

Cathepsin D (CatD) and tenascin C (Tn-C) have been implicated in invasion and metastasis of carcinomas. However, little is known about CatD and Tn-C distribution in mesenchymal tumors. Therefore, we aimed to investigate the expression of Tn-C and CatD in adipocytic tumors. Tn-C and CatD expressions in 27 lipomas, 5 atypical lipomatous tumor/well-differentiated liposarcomas (ALT/WDLS) and 11 liposarcomas (LS) were evaluated by immunohistochemistry and scored semiquantitatively. CatD expression was higher in ALT/WDLS than in lipomas (p<0.001), and higher in LS than in ALT/WDLS (p=0.009). Stromal Tn-C expression was higher in ALT/WDLS than in lipomas (p=0.02), but no difference was observed between ALT/WDLS and LS (p>0.05). These results indicate that Tn-C and CatD may be markers of locally aggressive or malignant behavior in adipocytic tumors.

[Axillary lymph node involvement in hormone-independent breast carcinomas]

BACKGROUND AND OBJECTIVE

We decided to study the axillary lymph node invasion (N) in hormone-independent breast cancer.

PATIENTS AND METHOD

The study group included 77 ER and 47 ER/PgR breast carcinomas. Both ER and PgR were determined using EIAS from Abbott (USA).

RESULTS

In ER tumors, one the most important finding was the high concentration (p = 0.001) and percentage of positives ( > 50 pmol/mg prot.; 24/41 vs 7/36; p < 0.01) of cathepsin D observed in N+ vs N- tumors. In ER/PgR negative tumors, lymph node involvement was associated with a same behavior of this proteinase (p = 0.021; 17/31 vs 2/16; p = 0.006) exclusively.

CONCLUSIONS

Our results point to a possible usefulness of cathepsin D in this type of carcinomas.

Prognostic value of cytosolyc cathepsin D content in resectable gastric cancer

BACKGROUND AND AIMS

Cathepsin D (Cath-D) is an aspartyl protease involved in protein catabolism and tissue remodelling. In the present article, we evaluate the tumor content of Cath-D in resectable gastric carcinomas and its relation with clinical and pathological parameters, as well as its prognostic significance.

METHOD

This prospective study included a series of 60 patients with primary gastric adenocarcinoma, who first underwent a complete surgical resection of their tumors and then were evaluated for disease recurrence and survival status during a mean follow-up period of 41.5 months. Cath D was measured in cytosolic samples using an immune-radiometric assay which determined the total amount of Cath-D (52K, 48K, and 34K).

RESULTS

The tumor content of Cath-D ranged from 4 to 247 pmol/mg protein and from 6.4 to 97.7 pmol/mg protein in adjacent non-neoplastic mucosa samples. Cytosolic Cath-D levels were significantly higher in neoplastic tissues (P < 0.001). Statistical analysis also demonstrated that younger patients showed lower Cath-D tumor levels than older ones. Likewise, patients with lower tumor levels of Cath-D had better survival than those with intermediate or high Cath-D tumor content (P = 0.002). This finding showed an independent prognostic value on survival (P = 0.02).

CONCLUSIONS

The present study demonstrates the presence of higher Cath-D content in gastric carcinomas than in adjacent non-neoplastic mucosa, and that high intratumor Cath-D levels identify a subgroup of resectable gastric cancer patients with a high probability of relapse as well as worse survival.

Tumor Tissue Levels of Tissue Inhibitor of Metalloproteinase-1 as a Prognostic Marker in Primary Breast Cancer

PURPOSE

In the present study, we investigated the association between tumor tissue levels of tissue inhibitor of metalloproteinase-1 (TIMP-1) and prognosis in patients with primary breast cancer and analyzed whether TIMP-1 may be useful as a prognostic marker in combination with urokinase plasminogen activator (uPA) and plasminogen activator inhibitor type-1 (PAI-1).

EXPERIMENTAL DESIGN

In cytosolic extracts of 2984 primary breast tumors, total levels of TIMP-1 were determined using an established, validated ELISA. Levels of uPA and PAI-1 have previously been determined in the extracts.

RESULTS

Univariate survival analysis showed a significant relationship between higher levels of TIMP-1 (continuous log-transformed variable) and poor prognosis [recurrence-free survival (RFS), overall survival (OS); P < 0.001]. Performing isotonic regression analysis, we identified a cut point to classify tumors as TIMP-1-low or TIMP-1-high. Using this cut point, high levels of TIMP-1 were significantly associated with shorter survival in univariate analysis, both in the total patient group (RFS, OS; P < 0.001), in the node-negative subgroup (RFS, hazard ratio = 1.28, P = 0.006), and in the node-positive subgroup (RFS, hazard ratio = 1.43, P < 0.001). In multivariate analysis, including uPA and PAI-1, TIMP-1 was significantly associated with shorter RFS, both when included as a continuous log-transformed (P = 0.03) and as a dichotomized variable (P = 0.002).

CONCLUSIONS

This study validates previous findings that tumor tissue levels of TIMP-1 are associated with prognosis in patients with primary breast cancer. It confirms that TIMP-1 may be useful as a prognostic marker in combination with uPA/PAI-1 and adds substantial positive information on the use of TIMP-1 as a prognostic marker in breast cancer.

Cathepsin D in ovarian cancer: prognostic value and correlation with p53 expression and microvessel density

OBJECTIVE

Overexpression of ubiquitous lysosomal aspartyl protease cathepsin D (CD) is involved in the progression of cancer. This study investigates the prognostic value and the association of cathepsin D expression with clinicopathological parameters, p53 expression, and angiogenesis in ovarian cancer.

METHODS

Cathepsin D was determined immunohistochemically in 43 ovarian tumors of low malignant potential (LMP) and 80 invasive tumors FIGO stage I-IV. Results were correlated with clinicopathological characteristics, p53, and microvessel density (MVD). Survival analysis of cathepsin D expression and MVD was performed in invasive tumors.

RESULTS

Epithelial tumor cathepsin D expression was more common in LMP tumors (65.1%) compared to invasive tumors (43.7%; P = 0.02). In LMP tumors, stromal cathepsin D was associated with mucinous tumors (P = 0.01), whereas in invasive tumors, epithelial cathepsin D expression was associated with clear cell tumors (P = 0.003). Invasive tumor cathepsin D had a negative relation to p53 expression. In LMP tumors, stromal cathepsin D correlated with microvessel density (P = 0.03). Stromal cathepsin D expression was an independent prognostic factor for disease-free survival (DFS) in patients with invasive cancer (P = 0.03, Cox regression), while cathepsin D expression missed to be of prognostic value for overall survival (OS) in invasive ovarian cancer. MVD had no influence on survival in invasive ovarian cancer (P > 0.05).

CONCLUSION

Our study demonstrates a prognostic value of cathepsin D expression in invasive ovarian cancer, while cathepsin D expression in LMP tumors seems to be linked to angiogenesis. The relation among cathepsin D, p53 expression, and angiogenesis demonstrates biological differences between invasive ovarian cancer and LMP tumors.

Cathepsin B and cathepsin D expression in the progression of colorectal adenoma to carcinoma

Lysosomal proteinases, cathepsin B (CB) and cathepsin D (CD) have been implicated in the progression of several human tumors. In the present study, the antigen levels of CB and CD, and their immunohistochemical staining were compared in paired colorectal tumors (n =64) and background colon tissue of the same patients with clinicopathological staging. The antigen levels, were found to be significantly higher in cancer tissue (mean 35.79 ng/mg protein for CB and 3.97 ng/mg protein for CD) than in corresponding normal mucosa (24.62 ng/mg protein for CB and 2.69 ng/mg protein for CD). CB antigen levels were positively correlated with differentiation grade and Duke's stage (P < 0.001 and P = 0.041, respectively), but not correlated with nodal status. CD antigen levels were not correlated with the previous parameters. Staining intensity for both antigens increased from adenoma to adenocarcinoma. The degree of staining for CB and CD was associated with differentiation grade (P = 0.004 and 0.001, respectively), Dukes' stage (P = 0.002 and 0.001, respectively) and lymph node involvement (P = 0.002 and P < 0.001, respectively).

Estrogen and progesterone receptor isoforms: clinical significance in breast cancer

The identification and exploitation of biomarkers that may predict response to anti-cancer treatments has the capacity to revolutionize the way that patients with cancer are treated. In breast cancer, the estrogen receptor (ER) and the progesterone receptor (PgR) are known to have a significant predictive value in determining sensitivity to endocrine therapies. Tumor expression of ER or PgR is known to affect clinical outcome and this information is often used to determine a patient's optimal treatment regimen. However, the measurement of ER and PgR alone is more complex than originally thought and the impact of the recently identified isoforms of ER (ERalpha and ERbeta) and PgR (PgRA and PgRB), as well as several variant and mutant forms, upon the choice of treatment remains unclear. Therefore, ER and PgR expression alone are unlikely to determine a patient's optimal treatment regimen, particularly when the amount of 'cross-talk' between different pathways, such as the epidermal growth factor receptor pathway, is considered. In order to account for the complex cell-signaling environment that occurs in breast cancer, multifactorial techniques are needed to analyze tumor biomarker expression. The recent advances in genomic- or proteomic-based approaches has enabled molecular portraits of breast cancers to be painted, allowing biomarkers of response and prognosis to be identified and characterized more accurately than before. In the future, patients could be treated according to the molecular portrait of their tumor biomarker expression, maximizing the therapeutic benefit that each patient receives.

Keeping Data Continuous when Analyzing the Prognostic Impact of a Tumor Marker: An Example with Cathepsin D in Breast Cancer

The prognostic value of cathepsin D has been recently recognized, but as many quantitative tumor markers, its clinical use remains unclear partly because of methodological issues in defining cut-off values. Guidelines have been proposed for analyzing quantitative prognostic factors, underlining the need for keeping data continuous, instead of categorizing them. Flexible approaches, parametric and non-parametric, have been proposed in order to improve the knowledge of the functional form relating a continuous factor to the risk. We studied the prognostic value of cathepsin D in a retrospective hospital cohort of 771 patients with breast cancer, and focused our overall survival analysis, based on the Cox regression, on two flexible approaches: smoothing splines and fractional polynomials. We also determined a cut-off value from the maximum likelihood estimate of a threshold model. These different approaches complemented each other for (1) identifying the functional form relating cathepsin D to the risk, and obtaining a cut-off value and (2) optimizing the adjustment for complex covariate like age at diagnosis in the final multivariate Cox model. We found a significant increase in the death rate, reaching 70% with a doubling of the level of cathepsin D, after the threshold of 37.5 pmol mg(-1). The proper prognostic impact of this marker could be confirmed and a methodology providing appropriate ways to use markers in clinical practice was proposed.