An evaluation of fatty acid-CoA ligase 4 in breast cancer

BACKGROUND

Fatty acid-CoA ligase 4 (FACL4) has been detected in various types of tumors. However, there is still very limited information about the role of FACL4 in breast cancer. Tissue microarray (TMA) technique analyzes thousands of specimens in a parallel fashion with minimal damage to the original blocks. This study was designed with the application of TMA to analyze the FACL4 status in breast cancer.

MATERIALS AND METHODS

Archival tissue specimens from 102 patients with primary invasive breast cancer were selected and FACL4 expression was analyzed by immunhistochemical staining with TMA. The data of primary tumor staging, age, estrogen receptor status, lymph node status, histological grading and TNM staging were also collected.

RESULTS

As shown my multivariate analysis, TNM stage was significantly related to the overall five-year survival rate. Nevertheless, FACL4 expression failed to have any significant relationship to overall five-year survival.

CONCLUSION

Immuno-histochemical staining with TMA was convenient and feasible for the analysis of FACL4 expression status in breast cancer. Our preliminary results showed that FACL4 expression had no significant prognostic value in breast cancer.

Protein tyrosine phosphatase kappa (PTPRK) is a negative regulator of adhesion and invasion of breast cancer cells, and associates with poor prognosis of breast cancer

PURPOSE

Receptor-like protein tyrosine phosphatase kappa (PTPRK) has been shown to exhibit homophilic binding. It is a putative tumour suppressor in primary central nervous system lymphomas and colorectal cancer. The present study investigated the expression of PTPRK in breast cancer and the biological impact of PTPRK on breast cancer cells.

METHODS

Expression of PTPRK protein and gene transcript was examined in a cohort of breast cancer patients. The association of PTPRK transcript level and pathological and clinical aspects was then analysed. Knockdown of PTPRK in breast cancer cells was performed using a specific anti-PTPRK transgene. The impact of PTPRK knockdown on breast cancer cells was investigated using in vitro cell function assays.

RESULTS

Lower levels of PTPRK transcripts were seen in the advanced breast cancer. The reduced PTPRK transcript levels were associated with poor prognosis of the disease. PTPRK transcript levels were decreased in the primary tumours of patients who died from breast cancer or had metastases. Patients with lower expression of PTPRK had shorter survival compared with those higher expression levels of PTPRK. Knockdown of PTPRK resulted in increased proliferation, adhesion, invasion, and migration of breast cancer cells in vitro.

CONCLUSIONS

Decreased expression of PTPRK in breast cancer is correlated with poor prognosis. PTPRK is a negative regulator of adhesion, invasion, migration, and proliferation of breast cancer cells. This suggests that PTPRK is a potential tumour suppressor in breast cancer.

Glutathione S-transferase Pi expression in invasive breast cancer and its relation with the clinical outcome

PURPOSE

Glutathione S-transferase (GST) is a cytosolic enzymatic system involved in cellular detoxifying process. In vitro studies have shown that the presence of this enzymatic system in breast carcinoma cells can accelerate the elimination of drugs commonly used in chemotherapy, thereby decreasing its efficacy. The aim of the present study was to evaluate the association between GST Pi expression by breast carcinoma cells and disease-free and overall survival.

METHODS

Ninety-five female patients with invasive breast carcinoma submitted to surgical treatment and adjuvant chemotherapy from January, 1995 to June, 1997 and followed until August, 2006 were evaluated. The expression of GST Pi in breast carcinoma cells, determined by immunohistochemistry, was correlated with several clinical and pathological parameters of prognostic significance.

RESULTS

There were 36 (37.9%) GST Pi-positive cases. GST Pi immunoexpression was not significantly correlated with patient's age, histological tumor type, clinical stage, hormone receptor status and survival. On the other hand, GST Pi positivity showed a significant correlation with a lower histological grade/C-erb-B2 negative breast carcinoma phenotype.

CONCLUSION

The findings suggest that GST Pi expression does not constitute a satisfactory prognostic factor in breast cancer.

Prognostic relevance of glucosylceramide synthase (GCS) expression in breast cancer

PURPOSE

Multidrug resistance (MDR) has been linked to sphingolipid metabolism and preclinical data ascribe glucosylceramide synthase (GCS) a major role for MDR especially in breast cancer cells but no profound data are available on the expression of this potential therapeutic target in clinical breast cancer specimens.

METHODS

We analyzed microarray data of GCS expression in a large cohort of 1,681 breast tumors.

RESULTS

Expression of GCS was associated with a positive estrogen receptor (ER) status, lower histological grading, low Ki67 levels and ErbB2 negativity (P < 0.001 for all). In univariate analysis there was a benefit for disease free survival for patients with tumors displaying low levels of GCS expression but this significance was lost in multivariate Cox regression.

CONCLUSIONS

Our results suggest ER positive tumors may be the most promising candidates for a potential therapeutic application of GCS inhibitors.

COX-2 localization within plasma membrane caveolae-like structures in human lobular intraepithelial neoplasia of the breast

Cyclooxygenase-2 (COX-2) is highly expressed in human intraepithelial neoplasia of the breast and takes part in the molecular pathway implicated in progression of breast cancer. Recently, we demonstrated that COX-2 protein is mainly located in plasma membrane of lobular intraepithelial neoplasia (LIN) cells suggesting a localization in caveolae-like structures. The aim of the present study is to establish subcellular locations of COX-2 and its colocalization with caveolin-1 (CAV-1) to caveolae structures in LIN. To establish a relationship between COX-2 and CAV-1, 39 LINs were studied by immunohistochemistry and confocal microscopy analysis. COX-2 and CAV-1 expression was observed respectively in 79.5 and in 94.9% of LIN studied. A positive correlation was found between membrane COX-2 staining pattern and CAV-1 expression, while no correlation was found between cytoplasm COX-2 staining pattern and CAV-1. Confocal analysis showed that COX-2 localized to plasma membrane was strictly associated to CAV-1 suggesting that an amount of COX-2 protein is placed in caveolae-like structures. Our results show that COX-2 is localized within caveolae compartment and colocalized with CAV-1 protein in LIN lesions. Because caveolae are rich in signaling molecules, this COX-2 compartment may play an important role in diverse breast cancer carcinogenesis processes.

Overexpression of the human homologue for Caenorhabditis elegans cul-4 gene is associated with poor outcome in node-negative breast cancer

BACKGROUND

Cul-4, a member of the Caenorhabditis elegans "cullin" ubiquitin-ligase gene family, plays a critical role in regulation of DNA-replication in this nematode. It has been suggested that cul-4 might have an important role in the development and progression of human cancer, but no data on this subject exist. The aim of this study was to investigate the expression and prognostic relevance of CUL-4 protein in lymph node-negative breast cancer, one of the most common malignancies worldwide.

MATERIALS AND METHODS

CUL-4 protein expression was determined with immunohistochemistry in 167 specimens of human node-negative invasive breast cancer with long-term follow-up. Results were correlated with overall and disease-free survival of patients.

RESULTS

Strong expression of CUL-4 protein was observed in 32 cases (19.2%), moderate expression in 59 (35.3%), weak expression in 64 (38.3%), and in 12 tumors (7.2%) no expression of CUL4 was observed. Patients with strong expression of CUL4 had a significantly shorter overall and disease-free survival (p = 0.04 and p = 0.029, respectively; Cox regression) compared to all other cases.

CONCLUSION

Our data provide evidence for the first time that CUL-4 could play an important role in the development and progression of human cancer.

Topoisomerase II alpha amplification may predict benefit from adjuvant anthracyclines in HER2 positive early breast cancer

BACKGROUND

TOP2A gene encodes topoisomerase II alpha, the direct molecular target of anthracyclines. This gene is frequently coamplified with HER2. The aims of this study were to analyse the pattern of TOP2A amplification and protein expression in relation to the molecular subgroups of breast cancers; and to define the impact of TOP2A amplification on the outcome of a series of patients homogeneously treated with adjuvant anthracyclines.

METHODS

A cohort of 245 patients with early breast cancer homogeneously treated with anthracyclines in the adjuvant setting was selected. A tissue microarray containing these cancers was used to determine HER2 and TOP2A gene copy number by means of chromogenic in situ hybridization. Immunohistochemical staining of topoisomerase II alpha was also performed using a monoclonal antibody (Ki-S1). TOP2A amplification and protein expression were correlated with classical prognostic parameters, expression of immunohistochemical markers and with a gene expression profiling classification using surrogate immunohistochemical markers. Kaplan-Meier method was used to construct survival curves and results were compared with log-rank test.

RESULTS

TOP2A amplification was restricted to tumours with HER2 amplification and was significantly associated with ER positivity. In the subgroup of patients with HER2 amplified tumours, TOP2A amplification predicted a better overall survival and disease free survival (P = 0.028 and 0.026, respectively). On multivariate analysis, TOP2A amplification maintained its predictive value for DFS.

CONCLUSION

TOP2A amplification is likely to be a useful marker to predict the subset of patients who will benefit from anthracyclines.

Evaluation of matrix metalloproteinase-2 (MMP-2) activity with film in situ zymography for improved cytological diagnosis of breast tumors

BACKGROUND

Fine-needle aspiration (FNA) biopsy of breast tumors is a reliable diagnostic method for identifying breast carcinoma. However, it is sometimes difficult to definitely distinguish malignant from benign lesions. To improve the cytological diagnosis of breast tumors, we investigated the expression of active matrix metalloproteinase-2 (MMP-2), as detected by film in situ zymography (FIZ).

METHODS

We evaluated 34 fresh breast tumors, 25 paraffin-embedded breast tissue specimens, and a human cancer cell line (HT1080). MMP-2 expression was determined by immunocytochemistry or immunohistochemistry. Frozen sections and aspiration cytology samples of breast cancer were incubated on gelatin-coated films for the detection of active MMP-2.

RESULTS

Immunohistochemistry showed that MMP-2 was expressed in cancer cells and stromal cells, but not in most benign breast lesions. Active MMP-2, but not pro-MMP-2, in the conditioned medium of HT1080 cells showed gelatinolytic activity on FIZ analysis, while the expression of both forms of MMP-2 was detected by immunocytochemistry. Gelatinolytic activity was also detected by FIZ analysis of aspiration cytology samples and frozen sections from the breast cancers, and there was a significant correlation between this gelatinolytic activity and the detection of MMP-2 expression by immunocytochemistry.

CONCLUSIONS

The present study demonstrated that measurement of gelatinolytic activity by FIZ analysis of aspiration cytology samples may be useful for improving the cytological diagnosis of breast tumors.

Estrogen-metabolizing enzymes in breast cancers from women over the age of 80 years

CONTEXT

Aromatase, steroid sulfatase, and 17beta-hydroxysteroid dehydrogenase type 1 (HSD-1) peripherally up-regulate, whereas estrogen sulfotransferase (EST) and HSD-2 down-regulate, the synthesis of active and more potent estrogens. These estrogen-metabolizing enzymes (EMEs) are important in postmenopausal breast cancers, but have never been systematically examined in breast cancers of the elderly.

OBJECTIVE AND DESIGN

mRNA levels of EMEs in cancerous and normal breast tissues from 39 elderly patients (age, 80-99 yr) were compared with those from 39 controls (age, 37-70 yr) or compared according to estrogen (ER)/progesterone (PR) receptor status.

RESULTS

Aromatase levels were higher in cancers of the elderly (EldCa) than in normal tissue of the elderly (P = 0.0008) or cancers of controls (P = 0.0033). In contrast, levels of steroid sulfatase and EST were higher in cancers of controls than normal tissue of controls (P = 0.0046 and P < 0.0001, respectively) or EldCa (P = 0.0001 and P < 0.0001, respectively). Levels of HSD-1 and HSD-2 did not differ significantly between any two of the categories. Among EldCa, HSD-1 levels were higher in ER/PR-positive than in ER/PR-negative carcinomas, whereas EST and HSD-2 exhibited opposite results.

CONCLUSIONS

The importance of aromatase is relatively increased in EldCa. ER/PR-positive EldCa exhibited a pattern of EMEs more beneficial to the production of estrogen than did ER/PR-negative EldCa. The specific pattern exhibited in EldCa may elucidate the role of EMEs in the absence of ovarian estrogens in the pathogenesis of breast cancer.

Overexpression of cyclooxygenase-2 is associated with a favorable prognostic phenotype in breast carcinoma

OBJECTIVES

Cyclooxygenase (COX) is the rate-limiting enzyme that catalyzes the conversion of arachidonic acid to prostaglandins. The purpose of the present study was to investigate the involvement of COX-2 protein in breast cancer biological behavior through its correlation with the well-known clinicopathological parameters and the expression of p53, c-erbB-2, topoisomerase IIalpha (topoIIalpha) and peroxisome proliferator-activated receptor (PPARgamma) proteins, as well as its effect on patients' survival.

METHODS

We performed immunohistochemistry to detect COX-2, estrogen receptor (ER), progesterone receptor (PR), p53, c-erbB-2, topoIIalpha and PPARgamma proteins in 175 cases of invasive breast carcinomas. The results were elaborated by statistic analysis.

RESULTS

Cytoplasmic expression of COX-2 was detected in 66.9% of breast carcinoma samples and was inversely correlated with both nuclear and histological grade (p < 0.0001 and p = 0.039, respectively), whereas its association with PR was found to be positive (p = 0.016). COX-2 expression was inversely correlated with topoIIalpha and p53 (p = 0.033 and p = 0.002, respectively), whereas its association with PPARgamma was parallel (p < 0.0001). In addition, c-erbB-2 of tumor cells was inversely correlated with COX-2 in stromal cells of the tumor (p = 0.011). Neither univariate nor multivariate analysis demonstrated any association between COX-2 expression and patient overall or disease-free survival.

CONCLUSIONS

The current data suggest that increased expression of COX-2 may be related to breast carcinomas with less aggressive phenotype. This suggestion is further supported by the positive correlation between COX-2 and PPARgamma, since the latter is considered to be indicative of a less malignant phenotype of tumor cells.

Polymorphisms of the promoter regions of matrix metalloproteinases genes MMP-1 and MMP-9 in breast cancer

PURPOSE

Matrix metalloproteinases play a crucial role in the cancer invasion and metastasis, angiogenesis and tumorigenicity. A single guanine insertion--the 1G/2G polymorphism in the promoter of the matrix metalloproteinase 1 (MMP-1) gene creates a binding site for the transcription factor AP-1 and thus may affect the transcription level of MMP-1. The C-->T substitution at the polymorphic site of the MMP-9 gene promoter results in a higher transcription activity of the T-allelic promoter trough the loss of binding site for a repressor protein. The aim of this work was to investigate the influence of 1G/2G and C-->T polymorphisms on the MMP-1 and MMP-9 level and therefore on the occurrence and progression of breast cancer.

EXPERIMENTAL DESIGN

We investigated the distribution of genotypes and frequency of alleles of the 1G/2G and C-->T polymorphisms for 270 patients with breast cancer and 300 healthy women served as control. The genotypes were determined by RFLP-PCR. Additionally, we estimated the level of MMP-1 and MMP-9 antigens in tumor samples and normal breast tissue using ELISA.

RESULTS

The levels of MMP-1 in tumor samples of node positive patients ware significantly higher than in samples of node negative patients (p<0.05). Increased level of MMP-9 correlates with Bloom-Richardson grading III (p<0.05), increased tumor size (p<0.05) and absence of estrogen and progesterone receptors (p<0.01). Additionally, both MMP-1 and MMP-9 levels were higher in tumor than in the normal breast tissue. We showed the higher risk of metastasis development in lymph node for the 2G/2G genotype (OR=2.14; CI 95% 1.24;3.69) and the 2G allele carriers (OR=1.68; CI 95% 1.19;2.39). We found correlation between the T allele (OR=2.61; CI 95% 1.33;4.87), 2G (OR=2.58; CI 95% 1.35;4.91) and malignance.

CONCLUSION

The results suggest that MMP-1 is responsible for the local invasion and MMP-9 is associated with the malignance and the growth of the tumor. We suggest that the 2G allele of the 1G/2G MMP-1 gene polymorphism may be associated with the lymph node metastasis in patients with breast cancer and therefore it can be considered as a progression marker in this disease.

UDP-N-acetyl-D-galactosamine: polypeptide N-acetylgalactosaminyltransferase-6 as a new immunohistochemical breast cancer marker

Mucin O-glycosylation is characterized in cancer by aberrant expression of immature carbohydrate structures (Tn, T, and sialyl-Tn antigens). The UDP-N-acetyl-D-galactosamine: polypeptide N-acetylgalactosaminyltransferases (ppGalNAc-T) family enzymes regulate the initial steps of mucin O-glycosylation and could be responsible for the altered glycosylation observed in cancer. Considering that we recently found the ppGalNAc-T6 mRNA expressed in breast carcinomas, we produced a highly specific monoclonal antibody (MAb T6.3) to assess the expression profile of ppGalNAc-T6 protein product in breast tissues. The expression of ppGalNAc-T6 by breast carcinoma cells was confirmed on MCF-7 and T47D cell lines. In formalin-fixed tissues, ppGalNAc-T6 expression was observed in 60/74 (81%) breast cancers, 21/23 (91.3%) adjacent ductal carcinoma in situ (DCIS), 4/20 benign breast lesions (2/2 sclerosing adenosis and 2/13 fibroadenoma), and in 0/5 normal breast samples. We observed a statistically significant association of ppGalNAc-T6 expression with T1 tumor stage. This fact, as well as the observation that ppGalNAc-T6 was strongly expressed in sclerosing adenosis and in most DCIS, suggests that ppGalNAc-T6 expression could be an early event during human breast carcinogenesis. Considering that an abnormal O-glycosylation greatly contributes to the phenotype and biology of breast cancer cells, ppGalNAc-T6 expression could provide new insights about breast cancer glycobiology.

Association of cyclooxygenase-2 and matrix metalloproteinase-2 expression in human breast cancer

Expression of cyclooxygenase-2 (COX-2) and matrix metalloproteinase-2 (MMP-2) associates with reduced survival in human breast cancer. COX-2 may be directly involved with mammary carcinogenesis, since expression of COX-2 is sufficient for formation of breast tumors in transgenic mice, and COX-2 selective inhibitors can suppress tumorigenesis in rodent models of breast cancer. MMP-2 is an extracellular matrix degrading proteolytic enzyme that bas been linked to invasion and metastasis. A direct link between COX-2 and MMP-2 may exist, since inhibition of COX-2 activity can result in reduction of MMP-2 expression and activity. In this study we analyzed protein expression of COX-2 and MMP-2 in tissue array specimens of 278 invasive breast cancers by immunohistochemistry. Immunopositivity of these two markers was correlated with each other and with various clinicopathological parameters including survival. We found high COX-2 expression in 30% and high MMP-2 expression in 83% of the breast cancer specimens, and there was a positive association between the expression of these two factors (p = 0.003). It was especially evident that whenever COX-2 expression was high, MMP-2 expression was almost invariably high (95%). Furthermore, high expression of either COX-2 or MMP-2 associated with decreased disease specific survival when compared with the COX-2 or MPP-2 low group (p = 0.026 and p = 0.021, respectively). Taken together, our results indicate that expression of COX-2 protein is associated with expression of MMP-2 protein in human breast cancer and that both COX-2 and MMP-2 are markers of poor prognosis in breast cancer.

Polo-like kinase isoforms in breast cancer: expression patterns and prognostic implications

Polo-like kinase (PLK) family members are known to be functionally involved in mitotic signaling and in cytoskeletal reorganization in both normal and malignant cells. In this study, expression of PLK1 and PLK3 was determined immunohistochemically in tissue specimens of 135 breast carcinomas, and expression was correlated with clinicopathological parameters and patient prognosis. Strong PLK isoform overexpression was observed in 42.2% (PLK1) and 47.4% (PLK3) of breast carcinomas when compared with non-transformed breast tissue. A positive correlation of PLK isoform expression with tumor grade, vascular invasion, erbB2/HER-2 expression and markers of proliferative activity was evident. Additionally, an inverse correlation of PLK isoform expression and estrogen receptor status was observed. Overexpression of PLK3 but not of PLK1 was significantly linked to reduced median overall (P<0.001) and relapse-free (P=0.021) survival time. PLK3 expression remained an independent prognostic factor for overall (RR=3.2, P=0.002) and relapse-free (RR=2.9, P=0.049) survival in multivariate survival analysis. These results suggest PLK3 as a novel independent prognostic marker in breast cancer and hint toward a role for PLK isoform overexpression in disease progression. Therefore, in vivo inhibition of PLK family members might represent a rewarding approach in the development of new anticancer drugs for this tumor entity.

Altered expression of the hormone- and xenobiotic-metabolizing sulfotransferase enzymes 1A2 and 1C1 in malignant breast tissue

Cytosolic sulfotransferases (SULTs) catalyze the biotransformation of steroid hormones as well as drugs and environmental toxins. Mostly, sulfonation leads to an inactivation of parent compounds, although formation of more toxic and cancerogenic metabolites also occurs. To assess possible alterations in the SULT enzyme expression pattern between malignant and non-malignant tissue, we studied the presence of 9 SULT enzymes of family 1 and 2 by semi-quantitative RT-PCR. Forty-two specimens from ductal and lobular breast carcinomas, lymph node metastasis, mastopathy and normal breast tissue were derived from 29 patients. Substantial expression of SULT 1A1, 1A2, 1A3, 1B1, 1C1, 1E1, 2A1, 2B1a and 2B1b mRNAs was observed in malignant and non-malignant tissue, although the pattern of the individual SULTs varied between the patients, and SULT1C1 mRNA was present in a greater number of malignant than non-malignant tissues (p<0.05). A major finding was that unspliced SULT1A2 mRNA, containing the complete intron between exons 7 and 8, was found in 4 of 16 non-malignant specimens, but was undetectable in the 26 malignant samples investigated. Taken together, the presence of various SULT enzymes in normal, premalignant and malignant breast tissue suggests an important role of SULT-mediated biotransformation in the breast. While the increased expression of SULT1C1 in malignant tissue seems to reflect tumor dedifferentiation, our finding of unspliced SULT1A2 mRNA in non-malignant tissue offers additional aspects regarding the search for breast cancer risk factors.

Expression of the ELAV-like protein HuR is associated with higher tumor grade and increased cyclooxygenase-2 expression in human breast carcinoma

PURPOSE

The human ELAV (embryonic lethal abnormal vision)-like protein HuR stabilizes a certain group of cellular mRNAs that contain AU-rich elements in their 3'-untranslated region. Cell culture studies have shown that the mRNA of cyclooxygenase (COX)-2 can be stabilized by HuR.

EXPERIMENTAL DESIGN

To investigate a possible contribution of dysregulation of mRNA stability to the progression of cancer and to overexpression of COX-2, we studied expression of HuR in 208 primary breast carcinomas by immunohistochemistry.

RESULTS

There were two different staining patterns of HuR in tumor tissue of breast carcinomas: nuclear expression was seen in 61% of cases; and an additional cytoplasmic expression was seen in 30% of cases. Expression of HuR was significantly associated with increased COX-2 expression; this association was particularly significant for cytoplasmic HuR expression (P < 0.0005). We further observed a significant association of cytoplasmic (P = 0.002) or nuclear HuR (P = 0.027) expression with increased tumor grade. Only 13% of the grade 1 carcinomas showed cytoplasmic expression of HuR, compared with 46% of the grade 3 carcinomas. There was no significant correlation between HuR expression and other clinicopathological parameters such as histological type, tumor size, or nodal status as well as patient survival.

CONCLUSIONS

Our results suggest that overexpression of HuR in tumor tissue may be part of a regulatory pathway that controls the mRNA stability of several important targets in tumor biology, such as COX-2. Based on our results, additional studies are necessary to investigate whether HuR might be a potential target for molecular tumor therapy.

Prognostic value of Topoisomerase II in female breast cancer

Topoisomerase II-alpha (Topo II-alpha) is a nuclear enzyme. Its expression rises rapidly at the end of the S to G2/M phase and falls after the mitotic process ends. We have studied the immunohistochemical expression of Topo II-alpha in breast cancer and its correlation with the menopausal state, tumor type, size, lymph node metastases, stage, and estrogen and progesterone positivity. Histological sections from 50 breast cancers were immunohistochemically stained for Topo II-alpha. The percent of positive cells at the area of highest staining was recorded as Topo index. The correlation between the course of disease, survival and Topo II-alpha index was statistically significant, p<0.001. High-grade tumors showed higher Topo II-alpha levels, than those of intermediate and low-grade, p<0.01. A significant association was found between estrogen receptors positivity and Topo II-alpha, p<0.05. A higher Topo II-alpha index indicates higher probability for recurrence of the disease and overall survival. Therefore, Topo II-alpha expression has a prognostic value in breast carcinoma.

Thioredoxin is associated with proliferation, p53 expression and negative estrogen and progesterone receptor status in breast carcinoma

We investigated the expression of thioredoxin and thioredoxin reductase in a large set of breast invasive and in situ carcinomas by immunohistochemistry. Additionally, NF-kappa B, p53 and proliferating cell nuclear antigen (PCNA) expression was studied. Thioredoxin and thioredoxin reductase expression was located in both cytoplasmic and nuclear compartments of the cell. Cytoplasmic thioredoxin positivity was found in 67 % and nuclear in 59 % of the cases, while thioredoxin reductase was found in 55 % and 6 % of cases, respectively. Ductal carcinomas showed stronger cytoplasmic thioredoxin immunoreactivity than lobular ones. Nuclear thioredoxin positivity was more often found in in situ lesions, and lobular carcinomas were more often negative than ductal ones. Both cytoplasmic and nuclear thioredoxin-positive cases had a high proliferation measured by PCNA staining. Positive nuclear immunostaining was associated with negative estrogen and progesterone receptor status. Cases with high p53 expression showed significantly higher nuclear thioredoxin positivity, but lower thioredoxin reductase positivity. Whilst thioredoxin or thioredoxin reductase was not associated with patient survival, cases showing both cytoplasmic and nuclear thioredoxin reductase-positive tumours had a shorter disease-free interval than those with negative immunostaining.

A Potential Role for the Estrogen-metabolizing Cytochrome P450 Enzymes in Human Breast Carcinogenesis

PURPOSE

The cytochrome P450 (CYP) enzymes play a critical role in the oxidative metabolism of a variety of endogenous and exogenous compounds, including drugs. Although intermediate CYP metabolites are believed to play a role in carcinogenesis, little is known about tissue-specific CYP expression and the role of local activation in breast carcinogenesis. The goals of this study are to identify CYPs expressed in breast tissue by measuring mRNA levels and to determine whether there are differences in mRNA levels between breast tumors and histologically-normal adjacent breast tissue.

EXPERIMENTAL DESIGN

Quantitative reverse-transcriptase polymerase chain reaction (RT-PCR) analysis was used to quantitate mRNA expression levels of 11 CYPs in 29 human breast tumor and non-tumor adjacent tissue pairs. The CYPs examined included: CYP1A1, CYP1A2, CYPB1, CYP2C8, CYP2C9, CYP2C18, CYP2C19, CYP2D6, CYP2E1, CYP3A4, and CYP3A5.

RESULTS

Only four CYPs were detected in breast tumor or adjacent tissue: CYP1A1, CYPB1, CYP2C9, CYP3A4. Each of these CYPs was expressed in at least 75% of the samples. Three of these CYPs are involved in estradiol hydroxylation (CYP1A1, 2-OH; CYP1B1, 4-OH; CYP3A4, 2- and 16-OH). CYP2C9 is involved in the conversion of estrone sulfate to the 16-hydroxy sulfate metabolite. Higher levels of CYP1B1 and 3A4 were found more often in non-tumor tissue than in tumor tissue (P < 0.04). CYP1A1 was elevated in non-tumor tissue only among pairs in which the tumor expressed the estrogen receptor (ER+, P < 0.03). All of these results were independent of recorded clinical-pathological covariates.

CONCLUSIONS

CYPs involved in estrogen metabolism are expressed in both tumor and non-tumor breast tissue. Local activation of estrogen to potentially reactive metabolites by the CYPs in breast tissue may play a role in initiating and promoting the carcinogenic process.

Plasma MMP-9 (92 kDa-MMP) activity is useful in the follow-up and in the assessment of prognosis in breast cancer patients

Previously we determined that plasma MMP-9 activity was significantly elevated in breast cancer patients compared to benign mammary pathologies and healthy controls. Now we analyzed its potential usefulness in the follow-up and in the prognosis of these patients. MMP-9 activity was measured by gelatin quantitative zymography in the euglobulin plasma fraction of 46 breast cancer patients in a 38-month follow-up study. Blood samples were obtained before surgery (S1), 1 month after (S2) and every 3 months. The relapse-free survival (RFS) and overall survival (OS) analysis was performed along 56 months in 113 patients using the Kaplan-Meier curves and Cox analysis. In 63% of the S2 analyzed, MMP-9 decreased after surgery. In 44 patients evaluated during the adjuvant period who developed a complete response, MMP-9 decreased compared to their S1, whereas 2 patients showed an enhancement in correlation with lack of response. Further analysis indicated that in all patients who never showed evidence of recurrence, plasma MMP-9 activity remained low, but it increased 1 to 8 months preceding the clinical detection of progression in those patients who relapsed. Kaplan-Meier curves indicated that high levels of plasma MMP-9 activity at the moment of breast cancer diagnosis were associated with a worse OS rate. Cox analysis showed it was not associated with tumor stage or patient's age. Our results, which show a good correlation between plasma MMP-9 activity and the clinical status of each patient, suggest its usefulness as a marker both in the follow-up and in the prognosis of breast cancer patients.

Expression of human delta-6-desaturase is associated with aggressiveness of human breast cancer

Highly unsaturated fatty acids (HUFAs) are cyto-toxic to cancer cells and generated in the body by desaturation from essential fatty acids, primarily involving delta-6-desaturase. This study, for the first time, examined the level of expression of human delta-6-desaturase as well as delta-4-desaturase in human breast cancer. Breast tumours (n=102) which comprised of 88 ductal and 14 lobular carcinomas, as well as normal breast tissues (n=31), together with breast cancer cell lines were analysed for the level of expression of delta-6- and delta-4-desaturases using RT-PCR and quantitative PCR. A lower level of delta-6-desaturase was seen in breast tumour compared with normal tissues. Tumours from patients who had a poor prognostic index and from those who died of breast cancer had the lowest level of delta-6-desaturase (median follow-up 72 months). In addition, TNM3 and TNM4 tumours had significantly lower level of delta-6-desaturase than TNM1 tumours. Interestingly, ductal tumours displayed significantly higher level of the enzyme than lobular tumours. In contrast, a stepwise increase of delta-4-desaturase was seen in tumour from patients with poor prognosis. It is concluded that aggressive breast tumours have a reduced level of delta-6-desaturase. This aberrant expression has clinical bearings to the outcome in patients with breast cancer.

Association between a glutathione S-transferase A1 promoter polymorphism and survival after breast cancer treatment

Glutathione S-transferase (GST) enzymes detoxify chemotherapeutic drugs, and several studies have reported differences in survival for cancer patients who have variant genotypes for GSTP1, GSTM1 or GSTT1 enzymes. A recently described polymorphism alters hepatic expression of GSTA1, a GST with high activity in glutathione conjugation of metabolites of cyclophosphamide (CP). To consider the possible influence of the reduced-expression GSTA1*B allele on cancer patient survival, we have conducted a pilot study of breast cancer patients treated with CP-containing combination chemotherapy. GSTA1 genotype was determined by polymerase chain reaction and restriction fragment length polymorphism. Kaplan-Meier methods and Cox proportional hazards models were used to evaluate survival in relation to genotype. Among 245 subjects, 35% were GSTA1*A/*A, 49% GSTA1*A/*B and 16% GSTA1*B/*B; the genotype distribution did not differ by ethnic group, age or stage at diagnosis. Among patients who had 0 or 1 GSTA1*B allele, the proportion surviving at 5 years was 0.66 (95% CI = 0.59-0.72), whereas for GSTA1*B/*B subjects the proportion was higher, 0.86 (95% CI = 0.67-0.95). Significantly reduced hazard of death was observed for GSTA1*B/*B subjects during the first 5 years after diagnosis, hazard ratio (HR) = 0.3, 95% CI = 0.1-0.8. The association varied with time, with no survival difference observed for subjects who survived beyond 5 years. These results, although based on a small study population, describe an apparent difference in survival after treatment for breast cancer according to GSTA1 genotype. Further studies should consider the possible association between the novel GSTA1*B variant and outcomes of cancer therapy.

Promoter hypermethylation of the death-associated protein kinase gene in breast cancer is associated with the invasive lobular subtype

Expression of death-associated protein (DAP) kinase, a proapoptotic serine/threonine protein kinase, is frequently lost in human tumors. In a study of 134 primary breast cancer specimens hypermethylation of the DAP kinase gene was found in 13% of cases. A highly significant difference (P < 0.001) of DAP kinase inactivation was observed between invasive lobular cancer (n = 19) and invasive ductal cancer (n = 85; 53% versus 9%, respectively). Hypermethylation correlated with loss of RNA expression, estrogen receptor positivity (P < 0.01), and the absence of p53 overexpression (P < 0.01). In contrast to invasive lobular cancer, the in situ-growing precursor lesion lacked epigenetic modification of the DAP kinase promotor by aberrant methylation indicating a potential role in tumor progression. Unlike the DAP kinase gene, hypermethylation of the cyclin D2 and RASSF1A genes did not correlate with a particular histological subtype or to invasiveness [corrected]. We conclude that different histological subtypes of breast cancer may not only differ concerning specific chromosomal abnormalities and DNA mutations but also with regard to epigenetic inactivation patterns.

Immunohistochemical expression of caspase-3 as an adverse indicator of the clinical outcome in human breast cancer

OBJECTIVE

Tumor growth is the net result of cell proliferation and cell loss by apoptosis. Caspase-3 (CPP32) has been considered as most directly correlated with apoptosis because of its location in the protease cascade pathway. The aim of this study was to examine the relation of the immunohistochemical expression of caspase-3 in 137 infiltrating breast carcinomas to patients' clinicopathological parameters and survival.

METHOD

A polyclonal antibody against caspase-3 was applied using a standard immunohistochemical procedure to paraffin sections.

RESULTS

By comparison with nonneoplastic breast tissue, caspase-3 appeared to be upregulated in malignant breast tissue, and its overexpression status was detected in 75.2% of the specimens. Significant statistical correlations were observed between overexpression of caspase-3 and low nuclear grade (p = 0.048), lack of p53 protein accumulation (p = 0.039), bcl-2-positive immunostaining (p = 0.027), as well as tissue inhibitor of metalloproteinase-2 immunoreactivity of neoplastic (p = 0.012) and stromal cells (p = 0.0001). Despite the above correlations, multivariate analysis revealed a significant negative influence of caspase-3 expression on patients' overall survival (p = 0.029).

CONCLUSIONS

Caspase-3 protein overexpression appears to be involved in the apoptotic pathways influenced by wild-type p53 and bcl-2 proteins. Moreover, the results show that caspase-3 overexpression in breast cancer cells seems to exert an independent adverse effect on patients' overall survival.

Tumor cell specific expression of MMP-2 correlates with tumor vascularisation in breast cancer

The metastatic potential of tumors is dependent on the ability of tumor cells to degrade extracellular matrix components by the expression of matrix metalloproteinases (MMPs) and to induce vascularisation of the tumor tissue. Thus, expression of MMPs and the number of blood vessel in tumor tissue may serve as prognostic markers of aggressive and metastasizing tumor growth. We have determined the vascularisation and the expression of MMP-2 by immuno-histochemical staining of 19 benign and 75 malignant breast tissue specimens with CD31- and MMP-2 specific antisera. The degree of vascularisation was expressed by intratumoral microvascular density (IMD), which takes into account all vessels present in a hot spot irrespective of their size. In addition, we have introduced a novel parameter, vascular grading (VG), which describes the percentage of small microvessels of <20 microm in diameter in the total number of blood vessels. IMD tended to indicate an elevated risk for metastasis formation and disease recurrence, while VG did not correlate with metastasis formation. Similarly, MMP-2 expression neither correlated with the clinical outcome of the disease nor with the classical histo-pathological parameters such as stage, grade, lymph node involvement and estrogen receptor status. Tumor cell-specific MMP-2 expression, however, showed a highly significant correlation with VG but not with IMD. These results indicate that MMP-2 expression is rather involved in the formation of small capillaries than in vessel maturation and tumor cell invasion. Thus, MMP-2 expression by tumor cells may serve as indicator of strong angiogenic induction potential of breast tumor cells.

Stromelysin-3 expression by mammary tumor-associated fibroblasts under in vitro breast cancer cell induction

To understand better the influence of the host stromal phenotype on stromal expression of stromelysin-3 (ST3) in breast cancer, we have investigated ST3 expression by host stromal cells isolated from 9 different primary breast carcinomas. These tumor-associated fibroblasts were cocultivated with 3 epithelial cancer cell lines of mammary origin (MDA-MB-231, SK-BR-3 and MCF-7), as well as with normal human mammary epithelial cells (NME and 184A1) and keratinocytes, using both direct and indirect coculture systems. ST3 expression was demonstrated by both in situ hybridization and immunocytochemistry. The results showed that ST3 expression by stromal cells was cancer-specific. Indeed, ST3 expression by tumor-associated stromal cells was induced by 3 malignant cancer cell lines (MDA-MB-231, SK-BR-3 and MCF-7), whereas no ST3 was expressed under normal mammary epithelial cell stimulation. ST3 expression was weak or absent in unstimulated tumor-associated fibroblasts. However, after direct coculture with cancer cells, expression of ST3 transcripts reappeared in 8 of the 9 cases and was observed only in fibroblasts located in close contact with tumor cells. Under similar coculture conditions and using the same cancer cell line stimulation, ST3 expression was, however, quite variable among these 9 cases, reflecting the difference of protease expression observed on the sections of the original tumors. Tumor induction of ST3 expression was much more important by direct cell-cell contact than by indirect stimulation and was not influenced by the addition of basic fibroblast growth factor (bFGF) and anti-bFGF to the culture medium. Our results suggest that the host stromal cell phenotype may significantly influence host stromal cell protease expression under cancer cell stimulation.

Gene expression for suppressors of telomerase activity (telomeric-repeat binding factors) in breast cancer

Mechanisms regulating telomerase activity and telomere length remain incompletely understood in human breast cancer. We therefore studied gene expression for telomeric-repeat binding factors (TRFs) in relation to telomerase activity, telomere length, and clinicopathologic factors in human breast cancer. Telomerase activity was detected in 65.8% of 38 breast cancers, but none of 16 noncancerous samples. Terminal restriction fragments were longer in noncancerous than in cancerous tissues, but not significantly. Among 8 patients with both cancer and paired noncancerous tissue available for terminal restriction fragments length assay, terminal restriction fragments were shorter in cancers than in paired noncancerous samples in all but one. Significantly more mRNA encoding TRF1 and 2 was detected in noncancerous than in cancer tissues. Additionally, expression of TRF1 and 2 mRNA was significantly higher in cancers without detectable telomerase activity than in cancers showing activity. Expression of these genes tended to show a negative correlation with terminal restriction fragments length, but this was not statistically significant. No correlation was seen between TRF1 or 2 mRNA expression, and clinicopathologic factors except for TRF1 with respect to tumor size and progesterone receptor status. In addition to reactivation of telomerase activity, escape from negative regulation of this activity is needed to maintain telomere length during cell proliferation in breast cancer. Genes encoding telomerase inhibitors might be of value in gene therapy against human breast cancer.

Prognostic significance of elevated cyclooxygenase-2 expression in breast cancer

Cyclooxygenase-2 (Cox-2) expression can induce mammary tumorigenesis in transgenic mice, and selective Cox-2 inhibitors are both chemopreventive and chemotherapeutic in rat models of breast cancer. We analyzed the expression of Cox-2 protein by immunohistochemistry in tissue array specimens of 1576 invasive breast cancers. Moderate to strong (elevated) expression of Cox-2 protein was observed in 37.4% of the tumors, and it was associated with unfavorable distant disease-free survival (P < 0.0001). Elevated Cox-2 expression was associated with a large tumor size, a high histological grade, a negative hormone receptor status, a high proliferation rate (identified by Ki-67), high p53 expression, and the presence of HER-2 oncogene amplification (P < 0.0001 for all comparisons), along with axillary node metastases and a ductal type of histology (P = 0.0001 and P = 0.0017, respectively). Interestingly, association with the unfavorable outcome was especially apparent in the subgroups defined by estrogen receptor positivity, low p53 expression, and no HER-2 amplification (P < 0.0001 for all comparisons). These results indicate that elevated Cox-2 expression is more common in breast cancers with poor prognostic characteristics and is associated with an unfavorable outcome. The present findings support efforts to initiate clinical trials on the efficacy of Cox-2 inhibitors in adjuvant treatment of breast cancer.

Prognostic role of Ape/Ref-1 subcellular expression in stage I-III breast carcinomas

The purpose of the study was to evaluate the prognostic role of the DNA repair protein APE/Ref-1 in breast carcinomas. Immunohistochemical analysis for APE/Ref-1 was performed in a series of 133 consecutive stage I-III breast carcinomas. The relationship between APE/Ref-1 and other prognostic and predictive factors such as tumor size, nodal status, histologic grade, p53 expression, hormonal receptor status, vascular invasion and necrosis was investigated. The prognostic value of APE/Ref-1 was studied by univariate and multivariate analysis. The predominant pattern of APE/Ref-1 immunohistochemical expression was nuclear, although cytoplasmic and mixed nuclear/cytoplasmic localization was also observed. The percentage of cells with APE/Ref-1 cytoplasmic stain directly correlated with the percentage of p53 positive cases (rho=0.28, p=0.013). The small group of women whose tumors showed mixed nuclear/cytoplasmic APE/Ref-1 localization (n=5) experienced a significantly poorer survival (p=0.014) and Cox proportional hazard model analysis identified APE/Ref-1 as an independent prognostic factor. The results suggest that subcellular localisation of APE/Ref-1 may influence the aggressiveness of breast carcinomas.

Collagenase-3 expression in breast myofibroblasts as a molecular marker of transition of ductal carcinoma in situ lesions to invasive ductal carcinomas

Collagenase-3 (matrix metalloproteinase 13; MMP-13), a protease originally identified in breast carcinoma, is characterized by a potent degrading activity against a wide spectrum of extracellular matrix proteins. The aims of this study were to localize and identify the MMP-13-expressing cells in invasive human breast carcinoma and to evaluate the role of MMP-13 in transition to invasive lesions by studying ductal carcinoma in situ (DCIS). We found expression of MMP-13 in stromal fibroblast-like cells in all 21 invasive ductal carcinomas studied and in 4 of 9 invasive lobular carcinomas. In most carcinomas, expression of MMP-13 was limited to small stromal foci in the tumor area. Combined in situ hybridization and immunohistochemistry showed coexpression of alpha-smooth muscle actin immunoreactivity and MMP-13 mRNA in myofibroblasts. In contrast, cytokeratin-positive cancer cells, alpha-smooth muscle actin-positive vascular smooth muscle cells, CD68-positive macrophages, and CD31-positive endothelial cells were all MMP-13 mRNA negative. In situ hybridization for MMP-13 in 17 DCIS lesions revealed expression in 10 cases. Immunohistochemical analysis of all DCIS cases identified microinvasion in 8 of the 17 lesions. Seven of the eight lesions with microinvasion were MMP-13 positive. Further analysis showed that MMP-13 expression was often associated with the microinvasive events. This particular expression pattern was unique for MMP-13 among other MMPs analyzed, including MMP-2, -11, and -14. We conclude that MMP-13 is primarily expressed by myofibroblasts in human breast carcinoma and that expression in DCIS lesions often is associated with microinvasive events. On the basis of these data, we propose that MMP-13 may play an essential role during transition of DCIS lesions to invasive ductal carcinomas.

Immunolocalisation of cytochrome P-450 3A enzymes in human breast carcinoma: relationship with tumour differentiation and steroid receptors

Cytochrome P-450 3A enzymes belong to the most abundant subfamily of the cytochrome P-450 system. They are predominantly found in the liver where they metabolize numerous drugs and endogenous substances such as oestrogens. However, they are also expressed by normal and tumoural extrahepatic tissues. Accordingly, immunolocalization was assessed in malignant breast tumours (n=32) and normal counterparts, by using a monoclonal antibody that recognizes all human CYP3A proteins. We investigated a potential relation between expression of CYP3A protein expression, the degree of tumour differentiation assessed by the histological grade and the proliferation index assessed by Ki-67 immunostaining. Immunodetection of CYP3A was observed in 27 of the 32 tumours analyzed (84%). A focal staining was also observed in the adjacent normal breast tissue in 33% of the samples, but expression was always fainter than in tumours. A significant negative association was found between CYP3A and the proliferation index, but there was no relation with receptor status or tumour differentiation. While CYP3A protein expression can be found in normal breast tissues, these data highlight higher and more frequent CYP3A in malignant breast cells. Such expression in malignant breast cells appears inversely related to the proliferation index whereas no relation is found with tumour differentiation.

Matrix-metalloproteinases 1, 2, and 3 and their tissue inhibitors 1 and 2 in benign and malignant breast lesions: an in situ hybridization study

Invasive growth requires degradation of extracellular matrix. Altered expression of matrix degrading enzymes may indicate an increased potential for invasive growth. We determined the expression patterns of matrix-metalloproteinases (MMP)-1, -2, and -3 and of the tissue inhibitors of metalloproteinases (TIMP)-1 and -2 by in situ hybridization with isotopically labeled RNA probes in normal breast tissue (n=6), fibrocystic disease (n=20), five cases of which contained radial scars, lobular carcinoma in situ (CLIS; n=5), ductal carcinoma in situ (DCIS; n=9) and invasive carcinomas (n=24). Only a few cells displayed MMP-1- and MMP-2-specific labeling in normal breast tissue and fibrocystic disease. Noninvasive ductal carcinomas showed elevated MMP-2 transcript levels in peritumor stromal cells in the absence of significant MMP-1 specific signals. In general, compared with adjacent normal breast tissue, a gradual increase of MMP-2 was found in noninvasive to invasive cancers. Invasive ductal and lobular carcinomas displayed co-expression of MMP-1 and MMP-2 by stromal cells, mainly of the invasion front, with high signal intensity particularly in high-grade invasive carcinomas. Tumor cells and peritumor stroma showed low MMP-3 transcript levels, especially in medullary carcinomas. TIMP-1 and -2 transcript levels were increased in invasive carcinomas correlating with the histological grade. These RNA expression patterns suggest an increased invasive potential in breast carcinomas even prior to histologically overt invasive growth.

The activity of thymidine phosphorylase correlates with tumor size and lymph nodes status in breast carcinoma

The platelet-derived endothelial cell growth factor (PD-ECGF) is one of the potent angiogenic factors. Recently, its homology with thymidine phosphorylase (dThdPase), an enzyme involved in pyrimidine nucleoside metabolism, has been shown. In the present study, dThdPase activity was evaluated spectrophotometrically in 43 breast carcinomas and in 19 cases of non-neoplastic breast tissues. The mean dThdPase activity in breast cancer was almost six fold higher than in normal, non-neoplastic breast tissues (1.92 and 0.29 mumol thymine (T) x mg prot.-1 x h-1 respectively). The enzyme activity significantly correlated with axillary lymph node status (p = 0.0076) and with tumor size (p = 0.0099). Besides, the intratumoral microvessel density (MD) was evaluated using the CD 31 mouse anti-human monoclonal antibody, and there was no correlation between the level of enzymatic activity and a number of microvessels. The positive significant correlation of thymidine phosphorylase activity with prognostic factors in breast cancer patients with no relation to the number of microvessels needs further examination to confirm the prognostic significance of the level of dThdPase.

Expression of MMP-2 and MMP-9, their inhibitors, and the activator MT1-MMP in primary breast carcinomas

Enhanced expression of the type IV collagenases MMP-2 and MMP-9, or lack of their inhibitors TIMP-1 and TIMP-2, has been associated with tumour invasion and metastatic potential in several experimental models. Regulation of enzyme activity is clearly a key step in tumour invasion, and recently a potent activator of MMP-2, the membrane-associated MT1-MMP, has been described and characterized. Using an immunohistochemical approach, this study has examined the expression and distribution of the type IV collagenases, their inhibitors, and the activator MT1-MMP, in a series of 79 infiltrating ductal carcinomas (IDCs), 8 tubular carcinomas, and 27 infiltrating lobular carcinomas (ILCs). MMP-2 and MT1-MMP were expressed in more than 90 per cent of all carcinomas, with predominantly stromal and tumour cell cytoplasmic staining. However, reactivity localized on tumour cell membranes was recorded for MMP-2 in 34 per cent of cases with a monoclonal antibody and 55 per cent of cases with a polyclonal antibody, and for MT1-MMP in 68 per cent of tumours. In each case, this pattern of staining was significantly associated with the presence of lymph node metastasis (p=0.001, p=0. 008, and p=0.1, respectively). Both tumour cell and stromal staining was observed for TIMP-2, but there was no correlation with metastatic status. The 92 kD gelatinase MMP-9 was expressed by 68 per cent of carcinomas, either in the stromal compartment or by tumour cells. There was a highly significant correlation between the expression pattern of MMP-9 and tumour type, with ILCs displaying greater frequency and more homogeneous cytoplasmic staining than IDCs (p=0.0004). Staining for TIMP-1 was seen in the stroma and also in relation to small blood vessels, with more than 90 per cent of tumours showing this staining pattern using a polyclonal antibody. This study indicates distinct patterns of expression for different MMPs and demonstrates the potential importance of the MMP-2/MT1-MMP system in breast tumour progression. The association of MMP-9 with the infiltrating lobular phenotype may reveal novel mechanisms of control for this metalloproteinase.

Presence of high levels of MT1-MMP protein in fibroblastic cells of human invasive carcinomas

Matrix metalloproteinase 2 (MMP2) activity is associated with the aggressiveness of human cancers. Therefore, the mechanisms regulating its activation are of great interest for a better understanding of malignant invasive processes. MT1-MMP, a membrane-bound MMP, is involved in the conversion of the latent form of MMP2 to the active one. In the present study, we have raised 3 monoclonal antibodies (Mabs) directed against 3 different epitopes of human MT1-MMP, which we used to investigate the expression and cellular localization of MT1-MMP protein in human carcinomas. MT1-MMP protein was present in all invasive carcinomas tested, and it was almost exclusively located to the stromal cells and not to cancer cells as previously reported, suggesting that MMP2 activation might be a peri-fibroblastic event.

Expression of cyclooxygenase-1 and cyclooxygenase-2 in human breast cancer

BACKGROUND

Numerous studies have demonstrated that the levels of prostaglandins are greater in various cancers, including breast cancer and colon cancer, than in normal tissues. In particular, the inducible form of cyclooxygenase (COX), the rate-limiting enzyme in prostaglandin biosynthesis, is overexpressed in colon tumors. Epidemiologic studies have demonstrated that the use of aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs) can reduce the risk of colon cancer and, to a lesser extent, the risk of breast cancer. NSAIDs are known to inhibit COX, suggesting that the beneficial effect of NSAIDs in colon cancer may be related to COX overexpression in this disease. This possibility led us to ask whether COX is also overexpressed in breast cancers.

METHODS

Surgical specimens from 44 patients with breast cancer who had undergone lumpectomy or mastectomy were analyzed by immunoblot analysis and immunohistochemical analysis to determine the expression profile of the constitutively expressed form of cyclooxygenase (COX-1) and the inducible form (COX-2); the specimens from 14 patients included normal breast tissue.

RESULTS

Expression of COX-1 protein was substantially higher in 30 of 44 tumor samples than in any of the 14 normal tissue specimens. Immunoblot analysis revealed extremely high levels of COX-2 protein in two tumor samples. Immunohistochemical staining of specimens that expressed COX-1 and/or COX-2 revealed that COX-1 was localized in stromal cells adjacent to the tumor but not in tumor cells. In contrast, COX-2 was localized primarily in tumor cells but also appeared in stromal cells.

CONCLUSION

Our results suggest that overexpression of COX may not be unique to colon cancer and may be a feature common to other epithelial tumors.

Stromelysin 3: an independent prognostic factor for relapse-free survival in node-positive breast cancer and demonstration of novel breast carcinoma cell expression

Stromelysin 3 (ST3) is a matrix metalloproteinase implicated in mammary carcinoma progression. To date, localization of ST3 expression in breast cancer by in situ hybridization and immunocytochemistry has shown that the expression of the enzyme is limited to only the stromal fibroblasts surrounding the cancer cells. We have immunostained a large group of ductal carcinoma in situ and invasive breast carcinomas using a monoclonal antibody (5ST-4A9) raised against the hemopexin-like domain of human ST3. We show that invasive lobular carcinomas express significantly less ST3 than invasive ductal carcinomas (IDCs) (P = 0.002). We also show, for the first time, that certain breast carcinoma cells that have undergone a degree of epithelial-to-mesenchymal transition, the so-called metaplastic carcinomas, can express ST3 mRNA and protein, which may in part explain the increased metastatic propensity seen in a number of these tumors. In addition, patients with IDC who had moderate to strong ST3 levels had significantly shorter disease-free survival than those with negative or weak ST3 levels (P = 0.02). Furthermore, in node-positive IDC patients, multivariate analysis revealed that ST3 level was a strong, independent prognostic parameter for disease-free survival (P = 0.005).

Telomerase activity correlates with tumor aggressiveness and reflects therapy effect in breast cancer

Telomerase appears to be an important factor for the control of cellular proliferation capacity and for tumorigenesis. Enzyme activity is highly increased in almost all human tumors and distinguishes them from benign lesions. Besides its diagnostic value, telomerase activity appears to be associated with tumor progression. The purpose of our study was to evaluate the significance of telomerase activity as a clinical marker in breast cancer. Twenty-five tumor samples from breast cancer patients were analyzed retrospectively for telomerase activity in chemotherapy-treated and untreated tumors. For each patient an identical number of cells was measured quantitatively for telomerase activity using the Telomerase-PCR-ELISA based on the TRAP (telomerase repeat amplification protocol) method. The findings were compared to clinical course, therapy and staging parameters. Telomerase activity was detected in all breast cancers. A significant correlation was found between enzyme activity and tumor size, lymph node status and stage: with ongoing tumor progression, telomerase activity appeared to increase in primary carcinomas. No correlation was seen between enzyme activity and the clinical course of patients. Without exception, telomerase activity was strongly decreased in all chemotherapy-treated tumors compared to untreated tumors. Our preliminary data indicate that telomerase activity is associated with aggressiveness of breast tumors and appears to mirror the anti-proliferative effects of chemotherapy.

Cysteine proteinase inhibitor cystatin A in breast cancer

Cystatin A (acid cysteine proteinase inhibitor; ACPI) is a natural inhibitor of cysteine proteinases. It has been suggested that an inverse correlation exists between cystatin A and malignant progression. We wanted to assess the biological and clinical significance of cystatin A in infiltrative breast carcinoma by immunohistochemical staining. Formalin-fixed paraffin-embedded material from 440 cases treated during the years 1988-1991 was used in the study. After exclusion of patients with disseminated disease at diagnosis, previous contralateral breast carcinoma, and absence of follow-up data, 384 patients could be included in the survival analysis. For immunohistochemical analysis of cystatin A, we used monoclonal cystatin A antibody WR-23/2/3/3, the binding of which was detected by the avidin-biotin-peroxidase method. Immunohistochemical analysis of Bcl-2 and p53 was also done, and mitotic activity was evaluated. Positive staining for cystatin A was found in 52 of 440 cases. The staining was irregular but showed irrefutably positive areas within neoplastic tissue. Most of the positive tumors were of the ductal infiltrative type, but two were mucinous carcinomas, one medullary and one squamous cell carcinoma. No lobular carcinomas showed positive staining. Focal cystatin A positivity was seen in myoepithelial cells of benign ducts. Occasional apoptotic bodies within the neoplasm showed strong positivity for cystatin A. Tumors positive for cystatin A were of larger size and had higher mitotic activity than cystatin A-negative tumors. Cystatin A was associated with negative Bcl-2 staining, but there was no statistically significant association between axillary lymph node status or p53 immunostaining. The risk for breast cancer-related death was significantly higher in patients with cystatin A-positive tumors than in those with cystatin A-negative ones. The risk increase was significant also in lymph node-negative patients. After adjusting for the effect of tumor size, histological grade, and lymph node status, cystatin A-positive patients still had a higher risk of death. Patients with cystatin A and p53 coexpression had a higher risk of death than the other patients. The findings reveal a new variant of aggressive breast cancer. This type of carcinoma may develop during tumor progression through genetic instability that allows cystatin A expression and gives growth advantage to a clone of tumor cells.

High levels of messenger RNAs for tissue inhibitors of metalloproteinases (TIMP-1 and TIMP-2) in primary breast carcinomas are associated with development of distant metastases

Tissue inhibitors of metalloproteinases (TIMPs) are believed to possess several cellular functions, particularly the contrasting activities of inhibiting tissue-degrading enzymes and promoting cellular growth. In attempts to elucidate which of these functions may prevail in breast cancer, expression of mRNAs for TIMP-1 and TIMP-2 in the primary carcinomas from 34 breast cancer patients was related to known prognostic parameters and the clinical outcome. High levels of TIMP-1 mRNA showed significant correlation with the presence of lymph node metastases (P = 0.0067), development of distant metastases (P = 0.014), and early death of the disease (P = 0.020). Elevated expression of TIMP-2 mRNA was associated with development of distant metastases (P = 0.0055). No correlations, however, were observed between mRNA levels of TIMPs and prognostic factors such as patient age, tumor size, grade of anaplasia, or steroid receptor status; neither were any correlations found between these clinicopathological characteristics and the mRNA expression of the collagenolytic enzymes matrix metalloproteinase-2 and matrix metalloproteinase-9. The present data suggest that high levels of TIMP-1 and TIMP-2 mRNAs in the primary carcinomas are strongly associated with development of metastasis in breast cancer.

Localization of mineralocorticoid receptor and 11 beta-hydroxysteroid dehydrogenase type II in human breast and its disorders

Mineralocorticoid receptors have been detected in the normal human breast and breast cancers. The expression of mineralocorticoid receptor (MR) and 11 beta-hydroxysteroid dehydrogenase type II (11sHSD2), which confers specificity on MR for aldosterone, was examined by immunohistochemistry in 114 samples from normal human breast and benign and malignant breast lesions in order to study its possible biological significance. MR and 11sHSD2 were immunolocalized in the ductal epithelium in 39/40 (98%) and 36/40 cases (90%) of normal breast, 21/22 (95%) and 15/22 cases (68%) of fibrocystic changes, and 11/11 (100%) and 8/11 (73%) cases of fibroadenoma, respectively. Cases positive for 11 sHSD2 also expressed MR but the patterns of expression varied greatly among examples of normal breast and benign breast diseases. There was a significant correlation between labeling indices of MR and 11sHSD2 in normal breast (p < 0.01) and in benign breast disease (fibrocystic change (p < 0.05) and fibroadenoma (p < 0.05)). In invasive carcinomas, immunoreactivity for MR and 11sHSD2 was detected in malignant cells in 32/41(78%) and 16/41(39%) cases. Both MR and 11sHSD2 labeling indices were significantly higher in invasive ductal carcinoma (22 cases) than invasive lobular carcinoma (19 cases) (p < 0.01). There was a significant correlation between labeling indices of MR and 11sHSD2 when analyzing all infiltrating carcinomas (p < 0.01), but not when assessing invasive lobular or invasive ductal carcinomas separately. These results indicate that the 11 sHSD2 enzyme generally colocalizes with the MR in the ductal epithelial cells of human breast, which may allow aldosterone to occupy its physiological receptor, and the expression of MR and 11sHSD2 appears to be related to ductal differentiation of breast carcinomas.

Telomerase expression in human breast cancer with and without lymph node metastases

Telomerase is a ribonucleoprotein enzyme that synthesizes telomeric DNA onto the ends of chromosomes, thereby preventing the replication-dependent shortening of these ends. Telomerase activity is detected in a wide range of cancers of various tissues, and its expression may be a critical step in tumor progression. The telomeric repeat amplification protocol was used to compare telomerase activity in breast cancers with and without lymph node metastases, as well as in fibroadenomas and normal breast tissue. Expression of telomerase was detected in 22 (79%) of 28 primary breast cancers, which included 16 (73%) of 22 cancers positive and 6 (100%) of 6 cancers negative for axillary lymph node metastases. It was detected in 1 (11%) of 9 fibroadenomas but was negative in 13 normal breast tissues. There was no statistical difference in expression of telomerase between axillary node-negative primary breast cancers and similar tumors with nodal metastasis (P = .289). Further, no statistical association was found between telomerase activity and tumor size (P = .679) or hormonal status (P = .178). The difference in telomerase activity among breast cancers vs fibroadenomas and normal breast tissues, however, was statistically significant (P < .001). Although normal breast tissue does not express telomerase, both node-positive and node-negative breast cancers express telomerase. The possible significance of telomerase expression in fibroadenomas remains open to further investigation.

Correlation of two methods for determination of cathepsin D in breast carcinoma (immunohistochemistry and ELISA in cytosol)

We have studied the correlation of two methods (immunohistology and ELISA in cytosol) of cathepsin D (CD) determination in breast carcinoma patients. Fifty six specimens of tumor tissue were collected consecutively, and CD expression in tumor tissue and tissue macrophages was determined by standard immunohistochemistry using the aNCL-CDm anti-cathepsin D mouse monoclonal antibody (Novocastra Laboratories Ltd., Newcastle, UK). Additionally, CD concentration was determined by ELISA in cytosol of the same breast carcinoma specimens. CD positivity was correlated with tumor size, histological grade of tumor, and the cytosol progesterone adn estrogen receptor concentrations. There was no statistically significant correlation between examined parameters and either CD positivity by immunohistochemistry or cytosol CD concentration. The correlation between CD expression in tumor cells of breast carcinoma by immunohistochemistry and cytosol CD positivity was not found either. However, there was a significant association between abundance of CD positive stromal macrophages and cytosol CD concentration in all histological tumor types (p < 0.05). CD positive macrophages were abundant in most of cytosol CD positive specimens. These results suggest that breast cancer cytosol CD concentration is the cumulative result of CD content in both carcinoma cells and stromal macrophages.

Aromatase and 17 beta-hydroxysteroid dehydrogenase type 1 in human breast carcinoma

The in situ formation of estradiol plays an important role in the development and biological behavior of human breast cancer Aromatase and 17 beta-hydroxysteroid dehydrogenase type 1 (17 beta-HSD type 1) are two principal enzymes involved in in situ estradiol production. We evaluated the expression of aromatase and 17 beta-HSD type 1 by immunohistochemistry in 41 cases of invasive breast carcinoma (19 lobular and 22 ductal). We then examined the correlation among the expression of these enzymes, estrogen (ER) and progesterone (PR) receptor status, Ki67 labeling index of carcinoma cells, age, and the clinical stage of the patients. Marked aromatase immunoreactivity was observed in stromal cells around carcinomatous glands in 32 of 41 cases (78%), and 17 beta-HSD type 1 immunoreactivity was detected in carcinoma cells in 23 of 41 cases (56%). There was a significant correlation observed between expression of 17 beta-HSD type 1 and aromatase in invasive lobular carcinoma (P = 0.0119), but not in invasive ductal carcinoma. There was an inverse correlation between aromatase and ER status in invasive ductal carcinoma (P = 0.0213), but not in invasive lobular carcinoma. No other correlations were observed among 17 beta-HSD type 1, aromatase, PR, ER, clinical stage, age, and Ki67 labeling indexes. Aromatase and 17 beta-HSD are not always expressed simultaneously in human breast carcinoma, but their simultaneous expression is more frequent in invasive lobular carcinoma than invasive ductal carcinoma. Consequently, different mechanisms may be involved in the regulation of expression of these two enzymes in human breast carcinoma.

Expression of aromatase protein and messenger ribonucleic acid in tumor epithelial cells and evidence of functional significance of locally produced estrogen in human breast cancers

The expression of aromatase by breast cancer cells and the role of locally produced estrogen in the stimulation of tumor growth has been controversial. The present study was performed to determine the site of aromatization in human breast cancers, using both immunocytochemistry and in situ hybridization. The functional significance of locally produced estrogens on growth of the tumor was addressed by measuring aromatase activity and a marker of proliferation (PCNA score). In addition, histocultures of some tumors were carried out to investigate whether testosterone aromatization could stimulate tumor proliferation. Of the 19 tumors investigated, 10 (52.6%) showed significant immunoreactivity to antiaromatase antibody in the cytoplasm of tumor epithelial cells and in surrounding stromal cells. The presence of aromatase mRNA detected by ISH was also located in tumor epithelial cells and stromal cell, and the pattern of expression was the same as with immunocytochemistry. In the ten tumors that showed immunoreaction to aromatase, the average aromatase activity measured in cryosections was 286.5 +/- 18.6 (SE) fmol estrogen/mg protein.h, whereas in nine tumors with weak aromatase immunoreaction, the enzyme activity was 154.7 +/- 19.3 (SE) fmol estrogen/mg protein-h (P < 0.05). The mean PCNA score was 33.8 +/- 5.1 (SE)% in strongly stained tumors and 20.8 +/- 2.0 (SE)% in weakly stained tumors (P < 0.05). Aromatase activity level and PCNA score were significantly correlated. In histoculture of four tumors, estradiol increased the incorporation of [3H]-thymidine into DNA. In two of these tumors, aromatase activity was high and [3H]-thymidine incorporation into DNA was also stimulated by testosterone. In the other two tumors that had low aromatase activity, no such stimulation occurred with testosterone. The results indicate that aromatase is expressed mainly in tumor epithelial cells and that sufficient amounts of estrogen are synthesized by the tumor to produce a proliferative response. It is concluded that estrogen synthesis by cancer cells could play a important role in promoting growth in a significant proportion of breast tumors.

Occult deposition of eosinophil peroxidase in a subset of human breast carcinomas

Degranulation of eosinophils has been observed in a variety of human tumors and in other diseases but has not been previously described in breast cancer. To determine whether eosinophil degranulation also occurs in breast carcinomas, we performed immunohistological studies on cryostat sections obtained from 26 breast cancer biopsies and from 2 benign breast tissues using a monoclonal antibody specific for human eosinophil peroxidase (EPO). For control purposes, the tissues were also immunostained with a mouse IgG1 negative control antibody and with monoclonal mouse anti-human myeloperoxidase. Of the 26 breast cancer specimens, 14 (53%) had extensive, unsuspected deposition of EPO that was located primarily in the connective tissue stroma around and within the tumor. Only 3 of the breast cancer cases had no immunohistochemical evidence of EPO. Thus, 23 of 26 cases of breast cancer (88%) had EPO deposits detectable within or around the tumor. By contrast, none of the benign breast tissues had similar deposits of EPO, and substantial extracellular myeloperoxidase deposition was detectable in only 3 cases of breast cancer. From these studies we conclude that there is eosinophil degranulation and extensive occult deposition of EPO in a major subset of human breast cancers.

Messenger RNA for urokinase plasminogen activator is expressed in myofibroblasts adjacent to cancer cells in human breast cancer

Urokinase plasminogen activator (uPA) is a serine proteinase involved in degradation of the extracellular matrix during cancer invasion. uPA is up-regulated in breast cancer, and high levels of uPA in tumor extracts are strongly associated with poor prognosis. Like several other matrix proteinases, uPA is in some types of cancer, including breast cancer, expressed by stromal cells. The present study was undertaken to determine the identity of the uPA-expressing stromal cells in breast cancer tissue. By in situ hybridization, a positive signal for uPA mRNA was in 26 of 28 ductal and four of five lobular carcinomas demonstrated in stromal cells adjacent to nests of cancer cells, whereas only one ductal carcinoma showed a positive reaction in the epithelial component itself. The positive stromal cells were found in both the peripheral and central parts of the tumors. Stromal cells surrounding carcinoma in situ lesions were uPA mRNA positive in a few cases, and no signal was observed in the neighboring nonmalignant tissue. Cell identification was done by immunostaining with Ab to markers for the following cell types: myoepithelial cells, myofibroblasts, smooth muscle cells, macrophages, endothelial cells, and epithelial cells. The only one of these cell types that had a distribution similar to the uPA mRNA-expressing cells was myofibroblasts, recognized as extravascular alpha-smooth muscle actin-positive and cytokeratin-negative cells. On adjacent sections, colocalization was found of cells positive for uPA mRNA and cells positive for alpha-smooth muscle actin and negative for cytokeratin. We concluded that the uPA mRNA-expressing cells are myofibroblasts. The myofibroblasts have previously been found to be abundant in breast cancer tissue. They primarily originate by differentiation of fibroblasts, probably induced by cytokines released from the cancer cells. The present findings suggest that the myofibroblasts, through production of uPA, play an active role in breast cancer invasion.

Immunocytochemical detection of DNA topoisomerase type II in primary breast carcinomas: correlation with clinico-pathological features

DNA topoisomerase type II (DT-II) is a major component of interphase nuclear matrix fractions, present in S-phase of the cell cycle. A series of 80 carcinomatous breast surgical samples was evaluated by immunohistochemistry, using a polyclonal antibody in a comparison with Ki-67 antiserum. A correlation with clinico-pathological data was also performed. Infiltrating ductal and lobular carcinomas constantly express DT-II with varying intensity of nuclear staining; a similar immunohistochemical pattern is observed with Ki-67. A frequent co-expression of DT-II and Ki-67 is encountered with double immunostaining; accordingly to these data, a linear relationship is evident when linear regression is employed. In addition, significant relationships between DT-II values and tumour size, histological grade and node involvement are shown, while an inverse correlation is appreciable between DT-II and oestrogen receptors and progesterone receptors. DT-II may be considered to be an additional operational marker for the proliferating fraction of cells in breast carcinomas.