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Combined use of microdissection and high-density oligonucleotide arrays is a powerful technique to study in vivo gene expression. Because microdissection generally yields ng quantities of RNA, RNA amplification is necessary but affects array results. We tested the reliability and reproducibility of oligonucleotide array data obtained from small sample amplified RNA isolated from primary tissues via laser capture microdissection, to determine whether gene expression measurements obtained under these now customary conditions are reliable and reproducible enough to detect authentic expression differences between clinical samples. We performed eight U133A Affymetrix GeneChip oligonucleotide array hybridizations using RNA isolated from a single normal human breast specimen: two standard and six small samples prepared using independent microdissections, RNA isolations, and amplifications. We then performed six array hybridizations using RNA obtained similarly from paired normal epithelium and ductal carcinoma in situ from three independent breast specimens. We determined reliability by analysis of hybridization quality metrics, and reproducibility by analysis of the number of more than twofold changed genes, linear regression, and principal components analysis. All amplified RNA generated good quality hybridizations. From the initial specimen, correlations between replicates (r = 0.96 to 0.99) and between small samples (r = 0.94 to 0.98) were high, and between standard and small samples (r = 0.84) were moderate. In contrast, in the three normal cancer pairs, the differences in gene expression were large among the normal samples, the ductal carcinoma in situ samples, and between normal and ductal carcinoma in situ within each pair. These differences were a much larger source of variability than the technical variability introduced by the processes of laser capture microdissection, small sample amplification, and array hybridization. Nanogram quantities of RNA isolated from primary tissue using laser-capture microdissection generates reliable and reproducible gene expression measurements. These measurements do not mirror those obtained using micrograms of RNA. Biological variability in gene expression between independent specimens, and between histologically distinct samples within a specimen, is greater than the technical variability associated with the procedures. Future studies of in vivo gene expression using this approach will identify functionally important differences within or between specimens.
J Mol Diagn 2005 Feb
PMID:Reliability and reproducibility of gene expression measurements using amplified RNA from laser-microdissected primary breast tissue with oligonucleotide arrays. 1568 75

The protein product of the HER2 oncogene is overexpressed in an estimated 25 to 30% of breast carcinomas and is considered an indicator of poor clinical outcome. The bcl-2 and the bcl-x-L genes are the 2 main genes of the bcl-2 gene family that suppress tumor cell death/apoptosis. HER2 gene amplification is also described in a percentage of cases of ductal carcinoma in situ (DCIS) of the breast. However, the relationship of such overexpression with the apoptosis-suppressing genes is currently unknown. A total of 37 consecutive cases of DCIS were immunostained for HER2 overexpression (clone CB11, Ventana), and expression of bcl-2 and bcl-x-L. DCIS cases were graded using the criteria of Holland et al. HER2 overexpression was scored 0 to 3+; 0 and 1+ were considered negative staining and 2+ and 3+ were considered positive staining. HER2 gene amplification was also confirmed with fluorescent in situ hybridization (FISH). HER2 was positive in 22 of the 37 DCIS cases (60%) in accordance with previous reports. Immunohistochemical overexpression of HER2 was also highly correlated with HER2 amplification by FISH. HER2 overexpression (confirmed by FISH) was mostly seen in grade II (9 of 17) and grade III (9 of 12) DCIS lesions. Only 1 of the HER2-amplified cases was a grade I lesion. Furthermore, HER2 overexpression correlated with the presence of necrosis (P=0.003). Similarly, of the cases overexpressing HER2 at the highest level (3+), 90% were grade II or grade III lesions. A total of 73% of these cases also exhibited necrosis. Overexpression of HER2 3+ was also highly correlated with the presence of the apoptosis-suppressing gene bcl-x-L (coexpression in 87% of cases, P=0.01) but not with the prototype apoptosis-suppressing gene bcl-2 (coexpression in 50% of cases, P value not significant). First, in DCIS overexpression of HER2 the majority of grade II and grade III lesions is seen, and this correlates with the presence of necrosis. Second, HER2 overexpression is also highly correlated with the expression of the apoptosis-suppressing gene bcl-x-L, but not with the prototype apoptosis-suppressing gene bcl-2. These differences may prove useful in defining groups of DCIS lesions with enhanced tumor cell growth and propensity for progression to invasion.
Appl Immunohistochem Mol Morphol 2005 Mar
PMID:Correlation of HER2 gene amplification with expression of the apoptosis-suppressing genes bcl-2 and bcl-x-L in ductal carcinoma in situ of the breast. 1572 88

Androgen receptor (AR) is known to be expressed in approximately 70 to 90% of invasive breast cancers, but there are still conflicting data in terms of AR expression in ductal carcinoma in situ (DCIS). The aim of this study was to evaluate AR expression in DCIS and to compare these results with nuclear grading and with other common endocrine-related markers. On this basis the authors performed immunohistochemical staining for estrogen receptor (ER)-alpha and ER-beta, progesterone receptor (PR), pS2, her-2/neu, and AR in 59 cases of DCIS (24 low grade, 5 intermediate grade, 30 high grade). They found a strong correlation of expression of ER-alpha (P=0.003), PR (P<0.0001), and nuclear grading. For AR expression, 44.1% of all DCIS were positive, but there was no correlation between nuclear grading (P=0.535) and the expression of the other factors. The authors conclude that AR expression in DCIS is not correlated with nuclear grading and with the expression of other known endocrine-related markers such as ER-alpha and -beta, PR, pS2, and her-2/neu. The immunohistochemical assessment of AR status, therefore, may not help in providing a more objective way of classifying DCIS.
Appl Immunohistochem Mol Morphol 2005 Mar
PMID:Androgen receptor expression in ductal carcinoma in situ of the breast: not a helpful marker for classification such as estrogen receptor alpha and progesterone receptor. 1572 90

The authors' previous studies revealed that a subset of ductal carcinoma in situ (DCIS) contained focally disrupted myoepithelial (ME) cell layers and basement membrane (BM). As the disruption of these two structures is a prerequisite for tumor invasion, and white blood cells (WBCs) contain digestive enzymes capable of degrading both the BM and damaged host cells, this study was designed to assess the possible roles of WBC in ME cell layer disruptions and tumor invasion. A total of 23 DCIS containing ducts with focally disrupted ME cell layers were selected from 94 such cases identified in the authors' previous studies. Two consecutive sections from each case were double immunostained, one with leukocyte common antigen (LCA) plus smooth muscle actin (SMA) and the other with Ki-67 plus SMA. Ducts lined by at least 50 epithelial cells and distinct ME cell layers were examined. A total of 191 duct cross-sections were found to contain focal ME cell layer disruptions; of these, 186 (97.4%) were with and 5 (2.6%) were without WBC infiltration. Of 207 morphologically similar sections without ME disruptions, 46 (22.2%) were with and 161 (77.8%) were without WBC infiltration. Ki-67-positive cells in ducts with focally disrupted ME cell layers were generally subjacent to ME cell layers, and more than 30 clusters of multiple proliferating cells were seen directly overlying or near focally disrupted ME cell layers. In contrast, Ki-67-positive cells in ducts without ME disruptions were scattered over the entire epithelial compartment. The significantly different frequency of WBC infiltration and clusters of multiple proliferating cells in ducts with and without ME disruptions suggests that WBCs might play important roles in ME disruption and tumor invasion.
Appl Immunohistochem Mol Morphol 2005 Mar
PMID:Mammary ducts with and without focal myoepithelial cell layer disruptions show a different frequency of white blood cell infiltration and growth pattern: implications for tumor progression and invasion. 1572 91

Aromatase inhibitors (AIs) have been in use to treat metastatic breast cancer for over 25 years. Recently potent and specific AIs have been introduced, which, because of their low toxicity profile, are being used in the adjuvant and neoadjuvant situation and also for the prevention of breast cancer. The two non-steroidal AIs, anastrozole and letrozole, and the steroidal AI, exemestane, have all shown superiority to tamoxifen as first-line treatment for advanced breast cancer. Interestingly, the oestrogen receptor downregulator, fulvestrant, was shown to be equivalent to anastrozole when compared as second-line therapy after the failure of tamoxifen. The first adjuvant AI trial began in 1996 and recruited over 9000 patients (ATAC trial). Anastrozole was compared with tamoxifen and a combination of the two drugs. There were no significant differences between tamoxifen and the combination. However, anastrozole showed about a 20% improvement in disease-free survival in ER+ disease compared with the other treatments. An overall survival analysis will be reported later this year. Two trials have compared 5 years of tamoxifen with 2-3 years of tamoxifen, followed by 2-3 years of AI (one trial (ITA) used anastrozole and another (intergroup) exemestane). Both trials show a disease-free advantage for the switch to AI. In another study (MA17) 5 years of tamoxifen was followed by a randomisation to letrozole or placebo and showed a significant disease-free advantage to the AI. Both letrozole and anastrozole show superiority to tamoxifen when used as a neoadjuvant therapy. Anastrozole significantly reduced contralateral breast cancer compared with tamoxifen, and this has led to two prevention trials: one in women at risk comparing anastrozole with placebo and the other after excision of DCIS comparing anastrozole with tamoxifen (IBIS II). The NCI Canada has also just initiated a trial of exemestane for prevention. Nearly all data available indicate that AIs are superior to tamoxifen. The important question is whether survival is improved when they are used as adjuvant therapy?
J Steroid Biochem Mol Biol 2005 Feb
PMID:Are aromatase inhibitors superior to antiestrogens? 1586 Feb 66

Breast cancer confined within the lactiferous duct or lobule, without invading the stroma, is called ductal carcinoma in situ (DCIS), whereas breast cancer that has invaded the stroma through the basal membrane is called invasive cancer. Heparanase, an endo-beta-D-glucuronidase that specifically degrades heparan sulfate proteoglycans (HSPGs) in the extracellular matrix (ECM), plays an important role when breast cancer cells breach the basal membrane. Recently, we have reported that heparanase is involved in angiogenesis through direct induction of cyclo-oxygenase-2 (COX-2). COX-2 induces vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) and is thus involved in neovascularization. The present study was undertaken to analyze surgically resected breast cancer specimens for heparanase and COX-2 expression, using specimens from 59 patients with invasive cancer and 85 patients with DCIS (including 41 cases of DCIS adjacent to invasive cancer). This study yielded the following results: a) the distribution of heparanase within tumor tissue was identical to that of COX-2; b) heparanase expression was more frequent in invasive cancer than in non-invasive cancer; c) a close positive correlation was noted between heparanase and COX-2 expression (this correlation was particularly strong in cases of invasive cancer); and d) COX-2 expression was always seen in cases positive for heparanase expression. Our results indicate that heparanase expression increases during the progression of breast cancer into invasive cancer, and that this change is accompanied by increased COX-2 expression. They also suggest that heparanase may play a novel role for COX-2 mediated tumor angiogenesis in breast-cancer progression.
Int J Mol Med 2006 Feb
PMID:COX-2 induction by heparanase in the progression of breast cancer. 1639 19

Immunohistochemistry is widely used for pathological diagnosis of breast lesions. Other than hormone receptors and HER2/neu analysis for primary breast carcinomas, several markers may be useful for differential diagnoses, although in limited situations. To decide the malignant potential of intraductal proliferative lesions, analysis for the staining pattern of cytokeratins may be a good reference. Most ductal carcinoma in situ cases are diffusely positive for luminal cell markers (CK8, CK18, CK19), but negative for basal cell markers (CK5/6 and CK14). However, usual ductal hyperplasia may show the mosaic staining patterns for any of these markers, which may indicate a heterogeneous cell population in benign lesions. Myoepithelial markers (alpha-SMA, myosin, calponin, p63, CD10) are almost consistently positive for benign papillomas but they do not completely distinguish intraductal papillary carcinomas. Preservation of myoepithelial layer is the diagnostic key when looking at benign sclerosing lesions, including carcinoma with pseudoinvasive structures. E-cadherin is mostly positive for ductal carcinomas but negative for lobular carcinomas. Some of the lobular carcinomas are positive for 34betaE12, but they are consistently negative for CK5/6. Comparison with histopathological findings of hematoxylin and eosin is essential to make proper diagnosis in the individual case.
Med Mol Morphol 2006 Mar
PMID:New trends of immunohistochemistry for making differential diagnosis of breast lesions. 1657 8

Many advanced human tumors including breast cancer overproduce plasmin that is known to promote angiogenesis and metastasis. The mechanism of this effect is poorly understood. Here we report that annexin II, an endothelial co-receptor for tPA (tissue-type plasminogen activator) and plasminogen, was undetectable in normal and hyperplastic ductal epithelial cells and ductal complexes. By contrast, it was consistently expressed in invasive breast cancer and ductal carcinoma in situ (DCIS) indicating its involvement in breast cancer. Using the well established invasive/metastatic MDA-MB231 cell line and the noninvasive/nonmetastatic MCF-7 human breast cancer cell line, we investigated the mechanism by which annexin II regulates breast cancer progression and metastasis. Western and Northern blot analyses demonstrate selective expression of annexin II in MDA-MB231 cells but not in poorly invasive MCF-7 cells suggesting its participation in invasive breast cancer. Since annexin II is a receptor for plasminogen, we tested whether MDA-MB231 cells are capable of producing plasmin in vitro. MDA-MB231 cell membranes induced plasmin generation in a time-dependent manner while those from MCF-7 cells failed to convert plasminogen to plasmin. The generated plasmin is capable of degrading ECM consequently facilitating cell invasion and migration, biological functions required for angiogenesis and metastasis. Plasmin generation and its dependent invasion and migration can be blocked by a monoclonal antibody to annexin II or angiostatin, potent inhibitors of angiogenesis, breast cancer, and metastasis. Our findings indicate that annexin II-dependent localized plasmin generation by human breast cancer cells could contribute to angiogenesis and metastasis. These results suggest that annexin II may be an attractive target for new anti-angiogenic and anti-breast cancer therapies.
Exp Mol Pathol 2006 Oct
PMID:Angiogenesis-associated protein annexin II in breast cancer: selective expression in invasive breast cancer and contribution to tumor invasion and progression. 1664 92

Aims-(1) To investigate whether loss of heterozygosity identified at various loci in invasive breast carcinoma or is present in lobular carcinoma in situ (LCIS). (2) To investigate whether LCIS is a monoclonal (neoplastic) or a polyclonal (hyperplastic) proliferation.Methods-Forty three cases of LCIS (30 with associated invasive carcinoma or in situ ductal carcinoma (DCIS) and 13 cases of pure LCIS) were investigated for loss of heterozygosity on chromosomes 16q, 17q, 17p, and 13q using a microdissection technique, polymorphic DNA markers, and the polymerase chain reaction (PCR).Results-Loss of heterozygosity was detected in both subgroups of LCIS at all the loci examined. There was no significant difference in the frequency of the loss between the group associated with invasive carcinoma and the pure LCIS group. The frequency of loss of heterozygosity ranged from 8% on 17p to 50% on 17q.Conclusions-Because of the nature of the technique employed, our findings show that LCIS is a monoclonal (neoplastic) proliferation rather than a hyperplastic proliferation. The incidence of loss of heterozygosity on 17p (D17S796) is lower than we have observed previously in DCIS, suggesting that LCIS and DCIS are different genetically as well as clinically and morphologically. The similar incidence of loss of heterozygosity on 16q and 17q, however, suggests that DCIS and LCIS may share a common pathway of evolution.
Clin Mol Pathol 1995 Apr
PMID:Loss of heterozygosity in lobular carcinoma in situ of the breast. 1669 85

Paracrine interactions between adipose fibroblasts and malignant epithelial cells are essential for structural and hormonal support of breast tumors. Factors derived from malignant epithelial cells inhibit adipogenic differentiation of fibroblasts and upregulate expression of aromatase, which stimulates estrogen synthesis and creates a localized, growth-stimulatory environment. Here, we characterized the gene expression profile of breast adipose fibroblasts in an in vitro model of malignancy to identify other paracrine interactions that support tumor growth. Primary breast adipose fibroblasts from cancer-free women were treated with conditioned media from malignant breast epithelial cells or normal breast epithelial cells, and differences in gene expression were identified by microarray. A total of 79 differentially regulated genes encoding cytokines, enzymes, angiogenic factors, cytoskeletal proteins, extra-cellular matrix remodeling proteins, signal transduction proteins and cell surface receptors were identified, and 6 of these were verified by real-time PCR. Among these, the expression of aldo-keto reductase family 1, member C3 (AKR1C3) was upregulated. AKR1C3 has multiple enzymatic properties, including conversion of estrone to estradiol and androstenedione to testosterone. Immunoreactive AKR1C3 was detected in epithelial and stromal components of benign lesions and ductal carcinomas in situ, and in 59.8% of epithelial and 69.6% of stromal cells in invasive breast carcinomas. AKR1C3 expression was significantly higher in myoepithelial cells surrounding the neoplastic epithelium of ductal carcinoma in situ compared with those surrounding benign epithelial lesions. Importantly, AKR1C3 and aromatase mRNA levels correlated positively in 61 malignant breast tumors (R=0.3967, p=0.00156). Malignant epithelial cell-conditioned medium significantly increased formation of testosterone and estradiol from androstenedione in breast adipose fibroblasts. In conclusion, malignant epithelial cell-derived factors significantly upregulate the enzymes AKR1C3 and aromatase that catalyze a series of complementary reactions to convert the circulating precursor androstenedione to biologically active estradiol in vitro in the stromal fibroblasts, and in vivo, in stromal component of breast tumors.
Mol Cell Endocrinol 2006 Jul 11
PMID:Paracrine-stimulated gene expression profile favors estradiol production in breast tumors. 1673 89


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