Activity In Breast Cancer Patients Research Articles

Epitope Characterization of an Aromatase Monoclonal Antibody Suitable for the Assessment of Intratumoral Aromatase Activity

Immunohistochemistry is one of the most suitable methods for the detection of intratumoral aromatase in order to identify patients who may respond to aromatase inhibitor therapy in hormone-dependent breast cancer. Previous studies showed statistically significant correlation between results of immnuohistochemistry and biochemical analysis in carcinoma components stained by aromatase monoclonal antibody 677. In this study, determination of the antigenic peptides recognized by aromatase antibodies through epitope mapping, combined with the new knowledge on aromatase-reductase interaction, provide insights for understanding various immunostaining patterns using different aromatase antibodies. Our studies on aromatase-reductase interaction also provided critical information on how aromatase and reductase interact with each other on the endoplasmic reticulum membrane, and identified key residues, including K108 of aromatase, that are involved in the interaction with reductase. Through epitope mapping and taking into consideration the interference with aromatase immunohistochemical staining by NADPH-cytochrome P450 reductase, we demonstrated that monoclonal antibody 677 is a suitable antibody for an assessment of intratumoral aromatase activity in breast cancer patients for making clinical management decisions. These results also provide valuable information to identify new aromatase antibodies for immunohistochemical diagnosis of hormone-dependent breast cancer in future.

Selective regulation of aromatase expression for drug discovery

Aromatase is a particularly attractive drug target in the treatment of hormone-responsive breast cancer, and aromatase activity in breast cancer patients is greater in or near the tumor tissue compared with the normal breast tissue. Complex regulation of aromatase expression in human tissues involves alternative promoter sites that provide tissue-specific control. Previous studies in our laboratories suggested a strong association between aromatase ( CYP19) gene expression and the expression of cyclooxygenase ( COX) genes. Additionally, COX selective inhibitors can suppress CYP19 gene expression and decrease aromatase activity. Our current hypothesis is that pharmacological regulation of aromatase can act locally to decrease the biosynthesis of estrogen and may provide additional therapy options for patients with hormone-dependent breast cancer. Two pharmacological approaches are being developed, one approach utilizing small molecule drug design and the second approach involving mRNA silencing technology. The small molecule drug design approach focuses on the synthesis and biological evaluation of a novel series of sulfonanilide analogs derived from COX-2 selective inhibitors. Combinatorial chemistry approaches were used to generate diversely substituted novel sulfonanilides. The compounds suppress aromatase enzyme activity in SK-BR-3 breast cancer cells in a dose and time dependent manner, and structure activity analysis does not find a correlation between aromatase suppression and COX inhibition. Real-time PCR analysis demonstrates that the sulfonanilide analogs decrease aromatase gene transcription in breast cells. Furthermore, the sulfonanilide compounds selectively decrease aromatase gene expression in several breast cancer cells, without exhibiting cytotoxic or apoptotic effects at low micromole concentrations. A ligand-based pharmacophore model for selective aromatase modulation (SAM) by the novel sulfonanilides identified an aromatic ring, two hydrogen bond acceptors, and a hydrophobic function as four key chemical features. In the second approach, short interfering RNAs (siRNA) were designed targeting human aromatase mRNA. Treatment of breast cancer cells with siRNAs targeting aromatase (siAROMs) completely masked the aromatase enzyme activity and resulted in suppression of CYP19 mRNA. Thus, these results suggest that the novel sulfonanilides and the siRNAs targeting aromatase expression may be valuable tools for selective regulation of aromatase in breast cancer.

Sexual Dysfunction after Premenopausal Stage I and II Breast Cancer: Do Androgens Play a Role?

Sexual dysfunction after breast cancer has been attributed to a variety of treatment associated and psychological factors. Data on the role of a treatment-induced decrease of testosterone for the development of sexual problems in breast cancer survivors have remained inconclusive. However, androgen metabolites constitute a more reliable measure for total androgen activity. To measure levels of total androgen activity in breast cancer patients and to investigate relevant predictors of sexual dysfunction after breast cancer. Twenty-nine patients with a premenopausal diagnosis of Stage I or II breast cancer and terminated adjuvant treatment, completed questionnaires on sexuality, quality of relationship, body image, and depression. In addition, blood samples were taken for the analysis of sex steroids. Female Sexual Function Index (FSFI), Relationship (PFB), Beck Depression Inventory, and European Organization for Research and Treatment of Cancer quality of life questionnaire. Analysis of dihydroepiandrosterone, dihydroepiandrosterone-sulfate, androstenedione, 17beta-diol, testosterone, dihydrotestosterone, androsterone, and ADT-G, 3-alpha-diol-3G, 3-alpha-diol-17G. Low levels of sex steroids reflected the medication-induced postmenopausal status independent of the type of chemotherapy treatment. Sexual dysfunction was present in 68% of the study group. Women with a history of chemotherapy were more affected in all of the FSFI-domains. The only predictor for desire was quality of relationship, while chemotherapy was predictive for problems with arousal, lubrication, orgasm, and sexual pain. Sexual satisfaction and higher FSFI sum scores were predicted by better quality of relationship and no history of chemotherapy, together explaining 54.2% and 49.7% of the variance. Sexual dysfunction after breast cancer is common and women should be informed properly at an early stage of treatment. Specific interventions have to be offered considering person-related preexisting factors and couples at risk should be supported in the transition to sexual life after breast cancer.

Multicenter phase I clinical trial of daily and weekly RAD001 in combination with vinorelbine and trastuzumab in patients with HER2-overexpressing metastatic breast cancer with prior resistance to trastuzumab

1057 Background: RAD001 (everolimus) is an oral inhibitor of the mTOR serine-threonine kinase, a downstream component of the PI3K/AKT signaling pathway playing a critical role in regulation of protein synthesis and ultimately cell growth, proliferation, and angiogenesis. RAD001 shows activity in breast cancer patients (pts) as both monotherapy and in combination with letrozole. Preclinical models demonstrate that RAD001 enhances the efficacy of trastuzumab. Loss of PTEN and AKT/mTOR activation have been reported to mediate resistance to trastuzumab. Methods: Vinorelbine was administered at a dose of 25 mg/m2, IV over 10–15 min on days 1 and 8 q3w. Trastuzumab 4 mg/kg loading dose administered IV over 90 min on day 1 (if pt was not already receiving trastuzumab), followed by weekly trastuzumab 2 mg/kg IV over 30 min. In the daily RAD001 arm, 2 cohorts were planned (5 and 10mg) and in the weekly RAD001 arm, 4 cohorts were planned (20, 30, 50 and 70mg). Treatment continues until progression or unacceptable t...

Association of low repair efficiency with high hormone receptors expression and SOD activity in breast cancer patients

Objectives: To evaluate the antioxidant status and repair capacity in breast cancer patients as well as the relationship between these parameters and expression of critical proteins in breast cancer tissue. Design and methods: Blood samples were obtained from 25 female breast cancer patients and 19 healthy women. The antioxidant status was determined by the concentration of thiobarbituric-reactive substances (TBARS) and activity of superoxide dismutase (SOD) and catalase (CAT). The basal DNA damage and repair capacity in lymphocytes were evaluated by comet assay. The expression of p53, c-erbB2, Ki-67, estrogen receptor (ER) and progesterone receptor (PR) in cancer tissue was detected by immunohistochemical staining. Results: The breast cancer patients presented significantly elevated endogenous DNA damage in lymphocytes and lower susceptibility to DNA damage induced by H 2O 2 when compared to the control group. There is a negative correlation between TBARS and sensitivity to peroxide induced DNA damage in patients. The percentage of residual damage after H 2O 2 treatment followed by 3h of post-incubation is significantly higher in patients and also correlates positively with SOD activity, ER and PR expression and negatively with the basal DNA damage. Conclusions: Our results demonstrate low repair capacity in lymphocytes of breast cancer patients and suggest that the regulation of DNA repair is sensitive to cellular redox state and can be modulated by ER/PR status.

Identification of predictive markers to differentiate ixabepilone from paclitaxel activity in ER-negative breast cancer patients

2525 Background: Ixabepilone (BMS-247550) is a microtubule stabilizing agent with demonstrable therapeutic value in taxane- refractory breast cancer (BC) patients. Biomarkers to predict either ixabepilone or paclitaxel activity in BC patients have previously been reported. However, markers that differentiate response to the two agents have yet to be identified. This study sought to discover predictive markers that will enable patient selection to differentially enhance response to ixabepilone or paclitaxel in ER-negative (ER-) patients. Materials and Methodologies: Pre-treatment gene expression profiles were generated for 62 ER- patients treated with ixabepilone in clinical study CA163080, and 51 ER- patients treated with T/FAC (paclitaxel and fluorouracil-doxorubicin-cyclophosphamide) in clinical study MDA133. Biomarkers differentially predictive of complete pathological response in breast were identified through gene set enrichment analysis (GSEA) or classification by threshold gradient descent (TGD). Gene knockdown by siRNA was used to study some of these candidate markers. Results: Four candidate models that differentiate response to ixabepilone treatment and taxane-containing therapy were identified. Two of the models, found by GSEA, are based on expression levels for single microtubule-related genes: transforming, acidic coiled-coil containing protein 3 (TACC3) and chromosome condensation protein G (HCAP-G). The potential of HCAP-G as a differential marker was supported by siRNA studies. Two of the models, found by TGD, are based on expression levels for 26 and 20 genes. Areas under the ROC curves for the models applied to each study separately are given in the table . Conclusions: We have identified four predictive models that differentiate response in a clinical trial of ixabepilone from that in a trial of T/FAC. A clinical trial is under way to further evaluate their utility for differentiating response to ixabepilone- and taxane-containing regimens. [Table: see text] [Table: see text]

Aromatase and COX in breast cancer: Enzyme inhibitors and beyond

Aromatase expression and enzyme activity in breast cancer patients is greater in or near the tumor tissue compared with the normal breast tissue. Complex regulation of aromatase expression in human tissues involves alternative promoter sites that provide tissue-specific control. Previous studies in our laboratories suggested a strong association between aromatase ( CYP19) gene expression and the expression of cyclooxygenase ( COX) genes. Additionally, nonsteroidal anti-inflammatory drugs (NSAIDs) and COX selective inhibitors can suppress CYP19 gene expression and decrease aromatase activity. Our current hypothesis is that pharmacological regulation of aromatase and/or cyclooxygenases can act locally to decrease the biosynthesis of estrogen and may provide additional therapy options for patients with hormone-dependent breast cancer. Two pharmacological approaches are being developed, one involving mRNA silencing by selective short interfering RNAs (siRNA) molecules and the second utilizing small molecule drug design. In the first approach, short interfering RNAs were designed against either human aromatase mRNA or human COX-2 mRNA. Treatment of breast cancer cells with siAROMs completely masked the aromatase enzyme activity. Treatment with COX-2 siRNAs decreased the expression of COX-2 mRNA; furthermore, the siCOX-2-mediated decrease also resulted in suppression of CYP19 mRNA. The small molecule drug design approach focuses on the synthesis and biological evaluation of a novel series of sulfonanilide analogs derived from the COX-2 selective inhibitors. The compounds suppress aromatase enzyme activity in SK-BR-3 breast cancer cells in a dose and time-dependent manner, and structure activity analysis does not find a correlation between aromatase suppression and COX inhibition. Real-time PCR analysis demonstrates that the sulfonanilide analogs decrease aromatase gene transcription in breast cells. Thus, these results suggest that the siRNAs and novel sulfonanilides targeting aromatase expression may be valuable tools for selective regulation of aromatase in breast cancer.

Tamoxifen Inhibits Cytochrome P450 2C9 Activity in Breast Cancer Patients

Tamoxifen has been reported to potentiate the anticoagulant effect of warfarin and also to increase the plasma level of phenytoin, which are mainly metabolized by CYP2C9. The aim of this study was to determine the influence of tamoxifen on CYP2C9 activity in vivo in humans.Thirteen breast cancer patients who would start tamoxifen following cytotoxic chemotherapy were enrolled in the study. A single oral dose of 25 mg losartan was given to the patients 2 days before and 2 weeks after starting tamoxifen therapy. Losartan and E3174 in 8-hour urine samples were measured by HPLC.Tamoxifen significantly increased the average urinary losartan/E3174 ratio from 0.73 (CI95%=0.15-2.30) to 1.66 (CI95%=0.68-5.20), after 2 weeks of treatment (p=0.002). Tamoxifen inhibited CYP2C9 activity in breast cancer patients within two weeks of its administration. The inhibition of CYP2C9 activity may be a possible explanation for the drug-drug interaction of tamoxifen with CYP2C9 substrates.

Minimal clinical benefit of single agent Orathecin (Rubitecan) in heavily pretreated metastatic breast cancer

The purpose of this phase II study was to evaluate the efficacy and tolerability of Orathecin, an oral camptothecin analog that has exhibited antitumor activity in breast cancer patients during preclinical studies. Sixteen patients with metastatic breast cancer previously treated with anthracycline and taxane were utilized in the study. Orathecin was administered orally at 1.5 mg/m2 /day for the first five consecutive days of the cycle followed by 2 days of rest on a 7-day schedule. The end points of the study were efficacy and toxicity. The median age of the patients was 51 years (range, 35-73). Eight patients (50%) had multiple disease sites, and nine patients (56%) received more than three chemotherapy regimens. All patients were evaluated for toxicity, three patients were removed from the study for toxicity or disease progression prior to 8 weeks and were thus not evaluated for efficacy. The median follow-up was 110 days (range, 15-554). There were no responses to treatment. Five of the 13 evaluable patients (38%) had stable disease, eight (61%) had progressive disease. Most adverse events were mild to moderate in intensity. The median time to progression (TTP) for evaluable patients was 109 days (range, 56-374 days) (lower 95% C.I., 57 days). The median survival time was 272 days (lower 95% C.I., 209 days). Orathecin at the dose and regimen used in this study resulted in no objective tumor responses for this heavily pretreated population. Accurate risk stratification strategies can improve patients' selection and contribute to determine the appropriate benefit of therapies in MBC.

HPMA copolymer–aminoglutethimide conjugates inhibit aromatase in MCF-7 cell lines

N-(2-Hydroxypropyl)methacrylamide (HPMA) copolymer–doxorubicin (Dox) has already shown clinical activity in breast cancer patients. Moreover, we have recently found that an HPMA conjugate containing a combination of both Dox and the aromatase inhibitor aminoglutethimide (AGM) shows significantly increased anti-tumour activity in vitro. To better understand the mechanism of action of HPMA copolymer–AGM conjugates several models were used here to investigate their effect on cell growth and aromatase inhibition. Cytotoxicity of HPMA copolymer conjugates containing AGM, Dox and also the combination AGM–Dox was determined by MTT assay in MCF-7 and MCF-7ca cells. Androstenedione (5 × 10− 8 M) stimulates the growth of MCF-7ca cells. Both free AGM and polymer-bound AGM (0.2–0.4 mg/ml) were shown to block this mitogenic activity. When MCF-7ca cells were incubated [3H]androstenedione both AGM and HPMA copolymer–GFLG–AGM (0.2 mg/ml AGM-equiv.) showed the ability to inhibit aromatase. Although, free AGM was able to inhibit isolated human placental microsomal aromatase in a concentration dependent manner, polymer-bound AGM was not, suggesting that drug release is essential for activity of the conjugate. HPMA copolymer conjugates containing aromatase inhibitors have potential for the treatment of hormone-dependant cancers, and it would be particularly interesting to explore further as potential therapies in post-menopausal women as components of combination therapy.

Translational studies on aromatase, cyclooxygenases, and enzyme inhibitors in breast cancer

Aromatase expression and enzyme activity in breast cancer patients is greater in or near the tumor tissue compared with the normal breast tissue. Regulation of aromatase expression in human tissues is quite complex, involving alternative promoter sites that provide tissue-specific control. Previous studies in our laboratories suggested a strong association between aromatase ( CYP19) gene expression and the expression of cyclooxygenase ( COX) genes. Our hypothesis is that higher levels of COX expression result in higher levels of prostaglandin E 2 (PGE 2), which in turn increases CYP19 expression through increases in intracellular cyclic AMP levels. This biochemical mechanism may explain the beneficial effects of non-steroidal anti-inflammatory drugs (NSAIDs) on reducing the risks of breast cancer. The effects of NSAIDs (ibuprofen, piroxicam, and indomethacin), a COX-1 selective inhibitor (SC-560), and COX-2 selective inhibitors (celecoxib, niflumic acid, nimesulide, NS-398, and SC-58125) on aromatase activity and CYP19 expression were investigated in breast cancer cell culture systems. Dose-dependent decreases in aromatase activity were observed following treatment with an NSAID or COX inhibitor, with the most effective agents being COX selective inhibitors. Real time PCR analysis of aromatase gene expression showed a significant decrease in mRNA levels in treated cells when compared to vehicle control. These results suggest that the effect of COX inhibitors on aromatase occurs at the transcriptional level. To further probe these interactions, short interfering RNAs (siRNA) were designed against either human CYP19 mRNA or human COX-2 mRNA. Treatment of breast cancer cells with aromatase siRNAs suppressed CYP19 mRNA and aromatase enzyme activity. Finally, treatment with COX-2 siRNAs downregulated the expression of COX-2 mRNA; furthermore, the siCOX-2-mediated suppression of COX-2 also resulted in suppression of aromatase mRNA. In summary, pharmacological regulation of aromatase and cyclooxygenases can act locally in an autocrine fashion to decrease the biosynthesis of estrogen and may provide additional therapy options for patients with hormone-dependent breast cancer.

Plasma concentration and activity of matrix metalloproteinase 2 and 9 in patients with breast disease, breast cancer and at risk of developing breast cancer

Matrix metalloproteinases (MMPs) are involved in extracellular matrix modification and associated with invasive and metastatic behavior of human malignant tumors. Specifically, MMP2 and MMP9 are implicated in both early and late processes of tumor development. It is reported that MMPs occur as inactive precursors, active enzymes or enzyme inhibitor complexes in biological samples. However, there is limited knowledge on the role of each form in disease and/or the significance of changes in the plasma concentration and/or activity in breast cancer patients. The aim of this study was to determine if patients with breast cancer, benign disease and at risk for developing breast cancer display characteristic levels of active and/or total MMP2 and MMP9 in plasma. Concentration and activity of MMP2 and MMP9 were determined quantitatively in the plasma of 124 female volunteers diagnosed with breast cancer ( n=31), benign disease ( n=38), or determined by the Gail Model to be at high risk ( n=31) or low risk (controls, n=24) of developing breast cancer. Data obtained was statistically analyzed to search for differences/patterns characteristic of each category. Concentration of total MMP2 was significantly lower in control individuals than benign, high risk ( P<0.001 respectively) and breast cancer patients ( P=0.002). Activity of total MMP2 was significantly lower in controls compared to cancer, benign and high risk patients ( P<0.001 respectively). Attempts to build a predictive/descriptive model using canonical discriminant analysis (utilizing all eight features; concentrations and activity levels of active/total MMP2 and MMP9) enabled the distinction of the controls from the high risk, benign and cancer groups. Our results suggest that preoperative plasma concentration and activity of MMP2 and MMP9 may permit sub-classification of female patients with breast disorders.

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors in breast cancer: current status and future development

Evidence suggests that the epidermal growth factor receptor (EGFR) and its ligands are involved in the pathogenesis of different human carcinomas, including breast cancer. Results of phase II clinical trials of EGFR tyrosine kinase inhibitors (TKIs) have shown that these compounds have little activity in breast cancer patients when used as single agents. The potential pitfalls of these clinical trials, and the molecular mechanisms that might be involved in regulating the sensitivity/resistance of breast cancer cells to EGFR TKIs are discussed in this brief article. In particular, preclinical findings clearly demonstrate that breast cancer cells are able to activate different mechanisms to escape the anti-tumor effects of drugs directed against growth factor-driven pathways. Therefore, it is conceivable that significant blockade of tumor growth might be obtained only through contemporary blockade of different growth promoting pathways, at least in advanced disease. In addition, preclinical and clinical findings support the use of EGFR TKIs in specific subgroups of breast cancer patients, such as estrogen receptor positive (ER+), tamoxifen resistant patients. In this regard, we describe potential future applications of these compounds in combination with other agents in the treatment of breast carcinoma.

Effect of tamoxifen on serum IL-18, vascular endothelial growth factor and nitric oxide activities in breast carcinoma patients.

Vascular endothelial growth factor (VEGF) is a multi-functional cytokine that has been suggested to be a major angiogenic factor in breast cancer. Nitric oxide (NO) is a potent biological molecule that participates in the multi-step process of carcinogenesis. Interleukin (IL)-18 has been shown to have potent anti-tumour effects. In this study, we investigated the effect of tamoxifen therapy on serum VEGF, NO and IL-18 activity in breast cancer patients. Serum levels of VEGF, nitrate + nitrite and IL-18 were measured in 34 postmenopausal breast cancer patients before and 3 months after the tamoxifen therapy. Both serum VEGF and IL-18 levels decreased after tamoxifen therapy (P = 0.051, P < 0.05, respectively). Serum VEGF levels increased in patients with endometrial thickness, while patients without endometrial thickness had a significant reduction in serum VEGF levels after therapy (P < 0.05). Serum nitrate + nitrite levels increased after the therapy, but this was not statistically significant (P > 0.05). A decrease in serum VEGF levels with tamoxifen therapy may be a reflection of reduced angiogenic activity in patients without endometrial thickness. The negative effect of tamoxifen therapy on IL-18, which is known to have a potent antitumour activity, may be related to the decreased tumour growth by induction of NO and reduction of VEGF activity as a feedback mechanism.

Tamoxifen inhibits cytochrome P450 2C9 activity: A possible mechanism for tamoxifen-warfarin interaction

2133 Background: Cytochrome P450 2C9 (CYP2C9) is a clinically important drug metabolizing enzyme, responsible for degradation of warfarin and some other drugs such as acenocoumarol, phenytoin, losartan, oral antidiabetics, non-steroidal anti-inflammatory drugs, etc. Tamoxifen has been reported to potentiate the anticoagulant effect of warfarin, and this interaction can be life-threatening. The mechanism of this interaction has not been identified, yet. Recently, urinary losartan/E-3174 (carboxy metabolite of losartan) ratio has been suggested as a marker for CYP2C9 metabolic activity. The aim of this study was to determine the influence of tamoxifen on CYP2C9 activity. Patients & Method: Six breast cancer patients that would start tamoxifen after adjuvant chemotherapy were included. A single oral dose of 25 mg losartan was given to the patients two days before and two weeks after starting tamoxifen therapy. Losartan and E-3174 in 8-hour urine were assayed by HPLC. The ratios of losartan/E-3174 before the tamoxifen treatment were compared to those during the treatment for each patient. Results: Tamoxifen increased the urinary losartan/E-3174 ratio in five of the patients, up to 6-fold (2.8-fold ± 0.8; mean ± SEM, p=0.03). Conclusion: Tamoxifen inhibits CYP2C9 activity in breast cancer patients as assessed with losartan as a probe drug. The inhibition of CYP2C9 activity may be the possible explanation for tamoxifen-warfarin interaction. CYP2C9 inhibition by tamoxifen may also be important for other CYP2C9 substrates with low therapeutic index like acenocoumarol, phenytoin and oral antidiabetics. (Supported by a grant from the Scientific and Technical Research Council of Turkey, SBAG-COST B15 –2356) No significant financial relationships to disclose.

Tartrate-resistant acid phosphatase 5b as a serum marker of bone metastasis in breast cancer patients.

Diagnosis and follow-up of bone metastases in breast cancer patients usually rely on symptoms and imaging studies. Tartrate-resistant acid phosphatase 5b (TRACP 5b) is a specific marker of osteoclasts and is herein proposed as a marker of bone metastasis in breast cancer patients. An immunoassay using a monoclonal antibody, 14G6, was used to measure the activity of serum TRACP 5b at pH 6.1 in 30 early breast cancer patients without bone metastasis and in 30 aged-matched breast cancer patients with bone metastasis. Another 60 normal volunteers were recruited as controls. Bone alkaline phosphatase (BAP), a traditional marker of bone turnover, was also measured in selected cases. The overall mean TRACP 5b activity in normal women was 2.83 +/- 1.1 U/l, and it increased with age. The mean TRACP 5b activity in early breast cancer patients did not differ from that of the normal group (2.93 +/- 0.64 vs. 2.83 +/- 1.1 U/l; p = 0.66), whereas it was significantly higher in breast cancer patients with bone metastasis (5.42 +/- 2.5 vs. 2.83 +/- 1.1 U/l; p < 0.0001). BAP activity was significantly higher in breast cancer patients with bone metastasis than in early breast cancer patients (p = 0.004). Serum TRACP 5b activity correlated well with BAP activity in breast cancer patients with bone metastasis (p < 0.0001), but not in normal individuals or in patients without bone metastasis. TRACP 5b activity can be considered a surrogate indicator of bone metastasis in breast cancer patients.

Tartrate-Resistant Acid Phosphatase 5b as a Serum Marker of Bone Metastasis in Breast Cancer Patients

Diagnosis and follow-up of bone metastases in breast cancer patients usually rely on symptoms and imaging studies. Tartrate-resistant acid phosphatase 5b (TRACP 5b) is a specific marker of osteoclasts and is herein proposed as a marker of bone metastasis in breast cancer patients. An immunoassay using a monoclonal antibody, 14G6, was used to measure the activity of serum TRACP 5b at pH 6.1 in 30 early breast cancer patients without bone metastasis and in 30 aged-matched breast cancer patients with bone metastasis. Another 60 normal volunteers were recruited as controls. Bone alkaline phosphatase (BAP), a traditional marker of bone turnover, was also measured in selected cases. The overall mean TRACP 5b activity in normal women was 2.83 ± 1.1 U/l, and it increased with age. The mean TRACP 5b activity in early breast cancer patients did not differ from that of the normal group (2.93 ± 0.64 vs. 2.83 ± 1.1 U/l; p = 0.66), whereas it was significantly higher in breast cancer patients with bone metastasis (5.42 ± 2.5 vs. 2.83 ± 1.1 U/l; p < 0.0001). BAP activity was significantly higher in breast cancer patients with bone metastasis than in early breast cancer patients (p = 0.004). Serum TRACP 5b activity correlated well with BAP activity in breast cancer patients with bone metastasis (p < 0.0001), but not in normal individuals or in patients without bone metastasis. TRACP 5b activity can be considered a surrogate indicator of bone metastasis in breast cancer patients.

Prognostic value of serum IL-18 and nitric oxide activity in breast cancer patients at operable stage.

Interleukin-18 (IL-18) is a multifunctional cytokine that was previously termed interferon-gamma-inducing factor. It has been suggested that serum IL-18 level may be used as a prognostic factor in some cancer types. Nitric oxide is a potent biologic molecule involved in the pathogenesis of cancer. In this study, we measured serum IL-18 and nitrate + nitrite levels in 56 patients with nonmetastatic breast cancer and 14 control subjects. Serum IL-18* and nitrate + nitrite** levels were significantly higher in patients with breast cancer when compared to the control subjects (*p < 0.05, **p < 0.001). Serum IL-18 levels were significantly higher in patients whose tumor size was greater than or equal to 5 cm when compared to patients whose tumor size was less than or equal to 2 cm (p < 0.05). Patients who were axillary lymph node negative (ALN) had lower serum IL-18 levels when compared to patients with positive ALN (p < 0.001). Serum IL-18 levels were significantly higher in patients with stage IIB or IIIA when compared to patients with stage I or IIA (p < 0.05). There was no significant difference in serum nitrate + nitrite levels in terms of age, tumor stage, estrogen receptor, and menopausal and ALN status (p > 0.05). In conclusion, serum IL-18 level may be a useful marker to predict prognosis of patients with breast cancer in complete remission after surgery. Long-term follow-up is required to clarify this hypothesis.

Significance of serum vascular endothelial growth factor, insulin-like growth factor-I levels and nitric oxide activity in breast cancer patients

Vascular endothelial growth factor (VEGF) is used to evaluate the angiogenic activity in breast carcinoma. Nitric oxide (NO) and insulin-like growth factor-I (IGF-I) are also implicated in breast tumorigenesis, including angiogenesis. We measured serum VEGF, IGF-I and nitrate+nitrite levels in 38 patients with metastatic and 23 with nonmetastatic breast cancer and in 16 controls. Serum VEGF and IGF-I levels were higher in patients with metastatic disease than in those with nonmetastatic disease or in controls ( P<0.001). Serum nitrate+nitrite levels were higher in patients with metastatic and nonmetastatic disease than in controls ( P<0.001). Patients with visceral metastasis and local metastasis had higher serum VEGF and nitrate+nitrite levels than patients with bone metastasis ( P<0.05). In the metastatic disease group, there was a positive correlation between serum VEGF levels and nitrate+nitrite levels ( r=0.436, P<0.05). Within the group with nonmetastatic disease, premenopausal patients had higher serum IGF-I levels than did postmenopausal patients ( P<0.001). NO may involve an angiogenic process that is stimulated by VEGF in breast carcinoma. Larger studies are required to clarify these suggestions.

WITHDRAWN: Significance of serum vascular endothelial growth factor, insulin-like growth factor-I levels and nitric oxide activity in breast cancer patients.

The publisher regrets that this is an accidental duplication of an article that has already been published in The Breast, 12 (2003) 1-9, doi:10.1016/S0960-9776(02)00214-X. The duplicate article has therefore been withdrawn.