Retinoblastoma and phosphate and tensin homolog tumor suppressors: impact on ductal carcinoma in situ progression

BACKGROUND

A subset of patients with ductal carcinoma in situ (DCIS) will progress to invasive breast cancer. However, there are currently no markers to differentiate women at high risk from those at lower risk of developing invasive disease.

METHODS

The association of two major tumor suppressor genes, retinoblastoma (RB) and phosphatase and tensin homolog (PTEN), with risk of any ipsilateral breast event (IBE) or progression to invasive breast cancer (IBC) was analyzed using data from 236 DCIS patients treated with breast conserving surgery with long-term follow-up. RB and PTEN expression was assessed with immunohistochemistry. The functional effects of RB and/or PTEN loss were modeled in MCF10A cells. Hazard ratios (HRs) were estimated with univariate and multivariable Cox regression models. All statistical tests were two-sided.

RESULTS

Loss of RB immunoreactivity in DCIS was strongly associated with risk of IBE occurrence (HR = 2.64; 95% confidence interval [CI] = 1.64 to 4.25) and IBC recurrence (HR = 4.66; 95% CI = 2.19 to 9.93). The prognostic power of RB loss remained statistically significant in multivariable analyses. PTEN loss occurred frequently in DCIS but was not associated with recurrence or progression. However, patients with DCIS lesions that were both RB and PTEN deficient were at further increased risk for IBEs (HR = 3.39; 95% CI = 1.92 to 5.99) and IBC recurrence (HR = 6.1, 95% CI = 2.5 to 14.76). Preclinical modeling in MCF10A cells demonstrated that loss of RB and PTEN impacted proliferation, motility, and invasive properties.

CONCLUSIONS

These studies indicate that RB and PTEN together have prognostic utility and could be used to target aggressive treatment for patients with the greatest probability of benefit.

Expression of underglycosylated MUC1 antigen in cancerous and adjacent normal breast tissues

INTRODUCTION

Mucin 1 antigen (MUC1) is a high-molecular-weight transmembrane glycoprotein with an aberrant expression profile in various malignancies, including breast cancer. Its increased overexpression and underglycosylation in breast cancer is associated with tumor invasiveness and metastatic potential. In this study, we took the next step toward establishing MUC1 as a potential diagnostic, prognostic, and therapeutic target by investigating its expression and posttranslational modification (glycosylation/sialylation).

PATIENTS AND METHODS

In these studies we used a breast cancer tissue microarray (TMA) and fresh-frozen multistage breast cancer tissues. We analyzed in detail the expression of normal and underglycosylated/sialated MUC1 by immunohistochemical techniques, real-time quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR), and various analytic techniques.

RESULTS

We found that changes in cellular localization as well as in upregulation and/or underglycosylation of MUC1 were associated with higher tumor grade. A key finding in this study was that underglycosylated MUC1 (uMUC1) overexpression and sialation were observed in tissues adjacent to tumor but identified as normal on pathology reports.

CONCLUSIONS

These findings suggest that uMUC1 can indeed be used as an early diagnostic marker and provide additional insights into breast cancer management.

False-positive and false-negative sentinel node findings in 473 breast cancers

We reviewed lymph node samples from 473 consecutive breast cancer cases with either negative sentinel nodes or isolated tumor cells to evaluate the rate of false-positive sentinel node findings. Nuclear morphometry was applied to compare nuclear atypia between the primary tumor and metastases classified as isolated tumor cells by size. In addition, the role of the diagnostic preoperative biopsy method, either core needle biopsy or fine needle aspiration cytology, on the prevalence of isolated tumor cells was investigated. In addition, we studied the expression of metastasis-associated protein 1 in the primary tumor and corresponding metastases in 95 cases, including 52 isolated tumor cell cases, to distinguish a true metastasis from a benign epithelial displacement. Our review revealed 4 false positives and 7 false negatives from 473 sentinel node cases. In addition, 5 true-positive cases were upstaged from isolated tumor cells to micrometastases. No association was found between the preoperative biopsy method and the sentinel node status (P=.859). There was no difference in nuclear atypia, when the cells in isolated tumor cells and primary tumor were compared. Therefore, small metastases do not represent benign epithelial displacement. Isolated tumor cell findings did not correlate with preoperative biopsy methods. The metastasis-associated protein 1 staining score sum was lower in the metastases than in the primary tumor in 72% of cases, including all sizes of metastases. These data suggest that metastasis-associated protein 1 staining is not ideal for investigating the possible malignant nature of smaller metastases because of the relatively low concordance between the primary tumor and metastases, even macrometastases.

N-WASP coordinates the delivery and F-actin-mediated capture of MT1-MMP at invasive pseudopods

Metastasizing tumor cells use matrix metalloproteases, such as the transmembrane collagenase MT1-MMP, together with actin-based protrusions, to break through extracellular matrix barriers and migrate in dense matrix. Here we show that the actin nucleation-promoting protein N-WASP (Neural Wiskott-Aldrich syndrome protein) is up-regulated in breast cancer, and has a pivotal role in mediating the assembly of elongated pseudopodia that are instrumental in matrix degradation. Although a role for N-WASP in invadopodia was known, we now show how N-WASP regulates invasive protrusion in 3D matrices. In actively invading cells, N-WASP promoted trafficking of MT1-MMP into invasive pseudopodia, primarily from late endosomes, from which it was delivered to the plasma membrane. Upon MT1-MMP's arrival at the plasma membrane in pseudopodia, N-WASP stabilized MT1-MMP via direct tethering of its cytoplasmic tail to F-actin. Thus, N-WASP is crucial for extension of invasive pseudopods into which MT1-MMP traffics and for providing the correct cytoskeletal framework to couple matrix remodeling with protrusive invasion.

Hypoxic conditions induce a cancer-like phenotype in human breast epithelial cells

INTRODUCTION

Solid tumors are less oxygenated than their tissue of origin. Low intra-tumor oxygen levels are associated with worse outcome, increased metastatic potential and immature phenotype in breast cancer. We have reported that tumor hypoxia correlates to low differentiation status in breast cancer. Less is known about effects of hypoxia on non-malignant cells. Here we address whether hypoxia influences the differentiation stage of non-malignant breast epithelial cells and potentially have bearing on early stages of tumorigenesis.

METHODS

Normal human primary breast epithelial cells and immortalized non-malignant mammary epithelial MCF-10A cells were grown in a three-dimensional overlay culture on laminin-rich extracellular matrix for up to 21 days at normoxic or hypoxic conditions. Acinar morphogenesis and expression of markers of epithelial differentiation and cell polarization were analyzed by immunofluorescence, immunohistochemistry, qPCR and immunoblot.

RESULTS

In large ductal carcinoma in situ patient-specimens, we find that epithelial cells with high HIF-1α levels and multiple cell layers away from the vasculature are immature compared to well-oxygenated cells. We show that hypoxic conditions impaired acinar morphogenesis of primary and immortalized breast epithelial cells grown ex vivo on laminin-rich matrix. Normoxic cultures formed polarized acini-like spheres with the anticipated distribution of marker proteins associated with mammary epithelial polarization e.g. α6-integrin, laminin 5 and Human Milk Fat Globule/MUC1. At hypoxia, cells were not polarized and the sub-cellular distribution pattern of the marker proteins rather resembled that reported in vivo in breast cancer. The hypoxic cells remained in a mitotic state, whereas proliferation ceased with acinar morphogenesis at normoxia. We found induced expression of the differentiation repressor ID1 in the undifferentiated hypoxic MCF-10A cell structures. Acinar morphogenesis was associated with global histone deacetylation whereas the hypoxic breast epithelial cells showed sustained global histone acetylation, which is generally associated with active transcription and an undifferentiated proliferative state.

Differentially expressed genes regulating the progression of ductal carcinoma in situ to invasive breast cancer

Molecular mechanisms mediating the progression of ductal carcinoma in situ (DCIS) to invasive breast cancer remain largely unknown. We used gene expression profiling of human DCIS (n = 53) and invasive breast cancer (n = 51) to discover uniquely expressed genes that may also regulate progression. There were 470 total differentially expressed genes (≥2-fold; P < 0.05). Elevated expression of genes involved in synthesis and organization of extracellular matrix was particularly prominent in the epithelium of invasive breast cancer. The degree of overlap of the genes with nine similar studies in the literature was determined to help prioritize their potential importance, resulting in 74 showing overlap in ≥2 studies (average 3.6 studies/gene; range 2-8 studies). Using hierarchical clustering, the 74-gene profile correctly categorized 96% of samples in this study and 94% of samples from 3 similar independent studies. To study the progression of DCIS to invasive breast cancer in vivo, we introduced human DCIS cell lines engineered to express specific genes into a "mammary intraductal DCIS" xenograft model. Progression of xenografts to invasive breast cancer was dramatically increased by suppressing four genes that were usually elevated in clinical samples of DCIS, including a protease inhibitor (CSTA) and genes involved in cell adhesion and signaling (FAT1, DST, and TMEM45A), strongly suggesting that they normally function to suppress progression. In summary, we have identified unique gene expression profiles of human DCIS and invasive breast cancer, which include novel genes regulating tumor progression. Targeting some of these genes may improve the detection, diagnosis, and therapy of DCIS.

Oestrogen-induced genes in ductal carcinoma in situ: their comparison with invasive ductal carcinoma

It is well known that oestrogens play important roles in both the pathogenesis and development of invasive ductal carcinoma (IDC) of human breast. However, molecular features of oestrogen actions have remained largely unclear in pure ductal carcinoma in situ (pDCIS), regarded as a precursor lesion of many IDCs. This is partly due to the fact that gene expression profiles of oestrogen-responsive genes have not been examined in pDCIS. Therefore, we first examined the profiles of oestrogen-induced genes in oestrogen receptor (ER)-positive pDCIS and DCIS (DCIS component (DCIS-c)) and IDC (IDC component (IDC-c)) components of IDC cases (n=4 respectively) by microarray analysis. Oestrogen-induced genes identified in this study were tentatively classified into three different groups in the hierarchical clustering analysis, and 33% of the genes were predominantly expressed in pDCIS rather than DCIS-c or IDC-c cases. Among these genes, the status of MYB (C-MYB), RBBP7 (RBAP46) and BIRC5 (survivin) expressions in carcinoma cells was significantly higher in ER-positive pDCIS (n=53) than that in ER-positive DCIS-c (n=27) or IDC-c (n=27) by subsequent immunohistochemical analysis of the corresponding genes (P<0.0001, P=0.03 and P=0.0003 respectively). In particular, the status of C-MYB immunoreactivity was inversely (P=0.006) correlated with Ki67 in the pDCIS cases. These results suggest that expression profiles of oestrogen-induced genes in pDCIS may be different from those in IDC; and C-MYB, RBAP46 and survivin may play important roles particularly among oestrogen-induced genes in ER-positive pDCIS.

Genomic and mutational profiling of ductal carcinomas in situ and matched adjacent invasive breast cancers reveals intra-tumour genetic heterogeneity and clonal selection

The mechanisms underlying the progression from ductal carcinoma in situ (DCIS) to invasive ductal carcinoma (IDC) of the breast are yet to be fully elucidated. Several hypotheses have been put forward to explain the progression from DCIS to IDC, including the selection of a subpopulation of cancer cells with specific genetic aberrations, and the acquisition of new genetic aberrations or non-genetic mechanisms mediated by the tumour microenvironment. To determine whether synchronously diagnosed ipsilateral DCI and IDCs have modal populations with distinct repertoires of gene copy number aberrations and mutations in common oncogenes, matched frozen samples of DCIS and IDC were retrieved from 13 patients and subjected to microarray-based comparative genomic hybridization (aCGH) and Sequenom MassARRAY (Oncocarta v 1.0 panel). Fluorescence in situ hybridization and Sanger sequencing were employed to validate the aCGH and Sequenom findings, respectively. Although the genomic profiles of matched DCI and IDCs were similar, in three of 13 matched pairs amplification of distinct loci (ie 1q41, 2q24.2, 6q22.31, 7q11.21, 8q21.2 and 9p13.3) was either restricted to, or more prevalent in, the modal population of cancer cells of one of the components. Sequenom MassARRAY identified PIK3CA mutations restricted to the DCIS component in two cases, and in a third case the frequency of the PIK3CA mutant allele reduced from 49% in the DCIS to 25% in the IDC component. Despite the genomic similarities between synchronous DCIS and IDC, our data provide strong circumstantial evidence to suggest that in some cases the progression from DCIS to IDC is driven by the selection of non-modal clones that harbour a specific repertoire of genetic aberrations.

Mechanism of MTA1 protein overexpression-linked invasion: MTA1 regulation of hyaluronan-mediated motility receptor (HMMR) expression and function

Even though the hyaluronan-mediated motility receptor (HMMR), a cell surface oncogenic protein, is widely up-regulated in human cancers and correlates well with cell motility and invasion, the underlying molecular and nature of its putative upstream regulation remain unknown. Here, we found for the first time that MTA1 (metastatic tumor antigen 1), a master chromatin modifier, regulates the expression of HMMR and, consequently, its function in breast cancer cell motility and invasiveness. We recognized a positive correlation between the levels of MTA1 and HMMR in human cancer. Furthermore, MTA1 is required for optimal expression of HMMR. The underlying mechanism includes interaction of the MTA1·RNA polymerase II·c-Jun coactivator complex with the HMMR promoter to stimulates its transcription. Accordingly, selective siRNA-mediated knockdown of HMMR in breast cancer cells substantially reduces the invasion and migration of cells. These findings reveal a regulatory role for MTA1 as an upstream coactivator of HMMR expression and resulting biological phenotypes.

Overexpression of a novel cell cycle regulator ecdysoneless in breast cancer: a marker of poor prognosis in HER2/neu-overexpressing breast cancer patients

Uncontrolled proliferation is one of the hallmarks of breast cancer. We have previously identified the human Ecd protein (human ortholog of Drosophila Ecdysoneless, hereafter called Ecd) as a novel promoter of mammalian cell cycle progression, a function related to its ability to remove the repressive effects of Rb-family tumor suppressors on E2F transcription factors. Given the frequent dysregulation of cell cycle regulatory components in human cancer, we used immunohistochemistry of paraffin-embedded tissues to examine Ecd expression in normal breast tissue versus tissues representing increasing breast cancer progression. Initial studies of a smaller cohort without outcomes information showed that Ecd expression was barely detectable in normal breast tissue and in hyperplasia of breast, but high levels of Ecd were detected in benign breast hyperplasia, ductal carcinoma in situ (DCIS) and infiltrating ductal carcinoma (IDCs) of the breast. In this cohort of 104 IDC patients, Ecd expression levels showed a positive correlation with higher grade (P = 0.04). Further analyses of Ecd expression using a larger, independent cohort (954) confirmed these results, with a strong positive correlation of elevated Ecd expression with higher histological grade (P = 0.013), mitotic index (P = 0.032), and Nottingham Prognostic Index score (P = 0.014). Ecd expression was positively associated with HER2/neu (P = 0.002) overexpression, a known marker of poor prognosis in breast cancer. Significantly, increased Ecd expression showed a strong positive association with shorter breast cancer specific survival (BCSS) (P = 0.008) and disease-free survival (DFS) (P = 0.003) in HER2/neu overexpressing patients. Taken together, our results reveal Ecd as a novel marker for breast cancer progression and show that levels of Ecd expression predict poorer survival in Her2/neu overexpressing breast cancer patients.

Live-cell imaging of tumor proteolysis: impact of cellular and non-cellular microenvironment

Our laboratory has had a longstanding interest in how the interactions between tumors and their microenvironment affect malignant progression. Recently, we have focused on defining the proteolytic pathways that function in the transition of breast cancer from the pre-invasive lesions of ductal carcinoma in situ (DCIS) to invasive ductal carcinomas (IDCs). We use live-cell imaging to visualize, localize and quantify proteolysis as it occurs in real-time and thereby have established roles for lysosomal cysteine proteases both pericellularly and intracellularly in tumor proteolysis. To facilitate these studies, we have developed and optimized 3D organotypic co-culture models that recapitulate the in vivo interactions of mammary epithelial cells or tumor cells with stromal and inflammatory cells. Here we will discuss the background that led to our present studies as well as the techniques and models that we employ. This article is part of a Special Issue entitled: Proteolysis 50 years after the discovery of lysosome.

The routine immunohistochemical evaluation in Paget disease of the nipple

Paget disease (PD) of the nipple with coexisting intraductal (DCIS) and invasive carcinoma of the breast comprises 0.6-1.8% of all malignant epithelial neoplasms of this organ. Unlike invasive ductal carcinoma, there are many controversies concerning histological features of PD and the significance of the immunohistochemical characteristics of this neoplasm, which limits the optimal treatment protocols. Therefore, we decided to verify the immunohistochemical markers of PD basing on the retrospective analysis of postoperative material from 69 patients treated surgically. Microscopic examination revealed partial (7 cases) or total (62 cases) replacement of the squamous epithelium of the nipple with nests of atypical glandular cells spreading in an area ranging from 0.2 to 2.5 cm. DCIS coexisting with the PD lesions was present in all examined patients, and infiltrating carcinoma occurred in 31 (44.9%) patients. Both intraepidermal and DCIS components presented c-erbB2 overexpression. Positive estrogen and progesterone receptor staining was observed only in 7 (10.1%) and 2 (2.7%) tumours, respectively. Ki-67 proliferation index of PD cells ranged from 10% to 30%, whereas in DCIS it varied from 4% to 20%. The value of Ki-67 index exceeding 25% in the intraepidermal component of PD was associated with worse overall survival rate.

[Clinicopathologic and immunohistochemical study of 187 cases of intraductal papillary neoplasm of breast]

OBJECTIVE

To evaluate the diagnostic approach and criteria for intraductal papillary neoplasms of breast.

METHODS

According to the criteria of 2003 WHO classification, 187 cases of intraductal papillary neoplasm of breast were identified and enrolled into the study. The clinical and histologic features were reviewed and immunohistochemical study for CD10, p63, CK14, CK5/6, CK7, MGB1 and p53 were carried out on 53 cases.

RESULTS

Amongst the 187 cases studied, there were 128 cases of intraductal papilloma, 16 cases of atypical intraductal papilloma and 43 cases of intraductal papillary carcinoma. They showed a spectrum of morphologic features including epithelial and stromal hyperplasia and secondary changes. The expression of myoepithelial markers, including CD10 and p63, significantly decreased in ascending order from intraductal papillomas, atypical intraductal papillomas and intraductal papillary carcinomas (P < 0.001). The expression of basal cell markers, including CK5/6 and CK14, showed a mosaic pattern in benign lesions and significantly decreased or was absent in atypical and carcinomatous lesions (P < 0.001). In contrast, the luminal cell marker CK7 expressed in the three groups with no statistically significant difference (P = 0.06). On the other hand, the expression of MGB1 in intraductal papillary carcinomas was much lower than that in the other two groups (P = 0.002 and P = 0.007). The staining for p53 was negative in all of the three groups.

CONCLUSIONS

Intraductal papillary neoplasms of breast represent a heterogeneous group of lesions with various morphologic appearances. Correlation with immunostaining results for myoepithelial markers, basal-type cytokeratins and luminal epithelial markers are helpful in arriving at a definitive diagnosis.

[Invasive carcinoma arising in breast microglandular adenosis: a clinicopathologic study of three cases and review of the literature]

OBJECTIVE

To study the clinicopathologic features, immunophenotypes and differential diagnoses of invasive carcinoma arising in breast microglandular adenosis (MGACA).

METHODS

Clinical and pathologic findings of 3 cases of MGACA were analyzed by histomorphology and immunohistochemical staining of CK7, S-100 protein, ER, PR, HER2, SMA, MSA, p63 and PAS. Literatures were reviewed.

RESULTS

(1) Histologically, 3 tumors all showed a spectrum of glandular proliferations ranging from microglandular adenosis (MGA) to atypical microglandular adenosis (AMGA) to in situ carcinoma (DCIS) to invasive carcinoma. The invasive carcinoma component was ductal in case 1, and matrix-producing in case 2 and case 3. (2) All epithelial cells in MGA, AMGA, DCIS and MGACA were positive for CK7 and S-100 protein, but were negative for ER and HER2. PR was negative in case 1 and case 2 but was low positive in case 3. Myoepithelial cell differentiation was not demonstrated in MGA, AMGA, DCIS and MGACA by immunohistochemical staining for SMA, MSA or p63. PAS staining showed the presence of basement membrane in MGA, AMGA and DCIS, except MGACA.

CONCLUSIONS

MGACA is an extremely rare tumor of the breast and has distinct morphological and immunohistochemical features. Further studies are needed to evaluate the clinical behavior of this rare neoplasm.

[Robo1 expression in breast cancer and its relationship to brain metastasis]

OBJECTIVE

To detect the expression of Robo1 in different breast tumors and its association with the breast cancer brain metastasis.

METHODS

Labelled streptavidin-biotin (LSAB) staining was used to examine the Robo1 expression in specimens from 24 cases of invasive ductal carcinoma (IDC) with brain metastasis, 71 cases of IDC without brain metastasis, 22 cases of ductal carcinoma in situ (DCIS) and 23 cases of fibroadenoma.

RESULTS

The expression pattern of Robo1 in DCIS (59.1%) and IDC (45.3%) was significantly lower than that in adenofibroma (87.0%, P < 0.05). The expression of Robo1 in IDC with brain metastasis (12.5%) was significantly lower than that in IDC without brain metastasis (56.3%, P < 0.05). The expression of Robo1 was much higher in more than 50 year-old-group (57.8%) than that in less than 50 year-old-group (34.0%) of IDC patients. The overall survival time in patients with the Robo1 negative expression was significantly shorter than those with positive expression (P < 0.05). No correlation was found between the Robo1 expression and the tumor size, lymph node metastasis, pathologic stage, histological grade and clinical stage (P > 0.05).

CONCLUSIONS

The Robo1 expression correlates negatively with IDC brain metastasis, and correlates positively with the age and prognosis of IDC patients. Robo1 may be applied as a marker in evaluation of the IDC prognosis and brain metastasis.

The impact of caveolin protein expression in tumor stroma on prognosis of breast cancer

We aimed to investigate the expression of caveolin-1, -2, -3, and platelet-derived growth factor (PDGF) β receptor in breast cancer cells and stroma by immunohistochemistry and to analyze their implications. The expression rates of stromal caveolin-2 and PDGF β receptor increased as the tumor progressed from ductal carcinoma in situ to microinvasive ductal carcinoma, intraductal component of invasive ductal carcinoma (IDC), and IDC (p<0.001). The expression loss of caveolin-1 in tumor stroma of IDC correlated with high tumor stage (p<0.001), high nodal stage (p=0.011), high cancer stage (p=0.005), estrogen receptor negativity (p=0.003), and tumor recurrence (p=0.003). In addition, the expression loss of caveolin-1 in tumor stroma was correlated with a shorter disease-free survival and an overall survival (p<0.001). In conclusion, the loss of stromal caveolin-1 is related to poor prognosis in IDC.

[Detection and clinical significance of Notch1 methylation in breast cancer and intraductal proliferative breast lesions]

OBJECTIVE

To explore the relevance between the promoter methylation status of Notch1 gene and the invasive ductal carcinoma and ductal hyperplastic lesions of the breast.

METHODS

Methylation status of Notch1 gene in human breast invasive ductal carcinoma (IDC, n = 89), ductal carcinoma in situ (DCIS, n = 20), atypical ductal hyperplasia (ADH, n = 11) and usual ductal hyperplasia (UDH, n = 20) were quantitatively evaluated by MALDI-TOF MS. The expression of Notch1 protein was detected by immunohistochemical stain (SP method).

RESULTS

Positive expression rates of Notch1 protein in IDC and DCIS were 91.0% (81/89) and 75.0% (15/20), respectively, which were significantly higher than those of ADH (4/11) and UDH (30.0%, 6/20;P < 0.05). Notch1 protein expression was correlated significantly with lymph node metastasis, pathological grades and TNM stages of IDC. The mean methylation levels of Notch1 gene at CpG_3, CpG_4.5 and CpG_8 significantly decreased in IDC group compared with those of DCIS, ADH and UDH groups (P < 0.0083). In breast carcinomas, the mean methylation rates of Notch1 gene at CpG_4.5, CpG_10.11, and CpG_14.15.16 loci in cases with axillary node metastasis were significantly lower than those without axillary node metastasis (P < 0.05); and the methylation rates at CpG_14.15.16 and CpG_18 loci in stage Iwere lower than that in stage II, further lower than that in stage III (P < 0.05); and that in CpG_1.2, CpG_12.13 loci in grade I (highly-differentiated group) were higher than that in grade II (moderate-differentiated group) and grade III (poorly-differentiated group) (P < 0.05); and the methylation rates at CpG_3, CpG_8 and CpG_14.15.16 loci in ER(+) PR(+) HER2(-) group were lower than that in ER(-) PR(-) HER2(+) group (P < 0.05).

CONCLUSIONS

There is an overall hypomethylation of Notch1 gene in breast invasive ductal carcinomas with corresponding over-expression of Notch1 protein. This inverse correlation show that the alteration of protein expression result from hypomethylation oncogene Notch1, and this change may have important significance in breast tumorigenesis and the development. Specific hypomethylation at CpG_3, CpG_ 4.5 and CpG_8 loci of Notch1 gene may play a role in the pathogenesis of breast carcinoma, suggesting the progression and/or malignant transformation from benign glandular lesions of the breast.

Topographical, morphological and immunohistochemical characteristics of carcinoma in situ of the breast involving sclerosing adenosis. Two distinct topographical patterns and histological types of carcinoma in situ

AIM

To examine the histopathological features of 24 surgically resected carcinoma in situ (CIS) involving sclerosing adenosis (SA), with special reference to the topographical relationship between CIS and SA.

METHODS AND RESULTS

In 13 (54%) lesions, CIS was entirely surrounded by SA (type A) and in 11 (46%), CIS involved SA at least focally but was not confined to the SA area (type B). The mean size of CIS in type B (30.45 mm) was significantly larger than in type A (18.00 mm). The mean size of SA in type A (39.46 mm) was significantly larger than in type B (19.54 mm). Most type A CIS were non-high-grade, and the oestrogen receptor (ER)(+)/progesterone receptor (PgR)(+)/HER2(-) immunophenotype predominated. Most type B CIS were high-grade and six (54%) were ER(-)/PgR(-). Most type A were bcl-2(+)/p53(-) in both SA and CIS areas, but two (18%) apocrine ductal CIS of type B were bcl-2(-)/p53(+) in both SA and CIS areas. Expression of ER and cyclin D1 in SA was not different from that of SA unassociated with cancer.

CONCLUSIONS

Most CIS involving SA arises within SA and high-grade DCIS tends to grow beyond SA. Occasional CIS may arise outside SA and secondarily involve SA.

[Correlation of TOP2A gene expression and survival of breast cancer patients]

OBJECTIVE

The aim of this study was to assess the TOP2A RNA expression and the relationship of TOP2A protein expression with metastasis-free interval in breast cancer patients.

METHODS

TOP2A expression was analyzed prior to surgery in 86 patients. The level of TOP2A gene amplification was analyzed by fluorescence in situ hybridization (FISH), its RNA expression level with RT-PCR, and their correlation with TOP2A protein expression was assessed by immunohistochemistry (IHC). The correlation between RNA expression level and metastasis-free interval in breast cancer patients was also analyzed.

RESULTS

Aberrations (amplification or deletion) of TOP2A copy number was observed in 25.6% (22/86) of the cases. TOP2A protein expression was detected in 66.3% (57/86) of the samples. There was a significant correlation between the TOP2A RNA expression and protein expression (P < 0.001). TOP2A gene expression was significantly associated with the metastasis-free interval in the breast cancer patients (P = 0.001). There was no significant correlation between TOP2A gene amplification and TOP2A protein expression (P = 0.211).

CONCLUSIONS

TOP2A RNA level is an objective and reliable prognostic indicator in breast cancer.

Lymphatic microvessel density, VEGF-C, and VEGFR-3 expression in different molecular types of breast cancer

BACKGROUND

Breast cancer is a heterogeneous disease and five major distinct molecular types have been characterized by gene analysis and immunohistochemistry. The molecular types of breast cancer have different behavior, a particular profile of response to therapy, reflected in the differential survival of patients. Previous findings showed a particular preference for lymph node and distant metastases of different molecular types, but the specific lymphangiogenic profile of these types is lacking.

PATIENTS AND METHODS

We investigated the differential expression vascular endothelial growth factor-C (VEGF-C), vascular endothelial growth factor receptor-3 (VEGFR-3) and D2-40 by immunohistochemistry, to evaluate lymphangiogenesis and the lymphatic microvessel density (LMVD), in patients with breast cancer, stratified according to the molecular classification.

RESULTS

There was a differential expression of VEGF-C/VEGFR-3 and D2-40 in different molecular types of breast cancer, with highest level of expression for these markers being found in HER2 and luminal B types and the lowest in basal-like type. The lowest value of both intratumoral and peritumoral LMVD were found in normal-like type breast cancer. VEGF-C expression did not correlate with the grade of the tumor, but a significant correlation was found with lymph node metastasis. VEGFR-3 expression was found in 66.66% of the cases and correlated with the expression of VEGF-C in tumor cells. There was a positive correlation between VEGF-C, VEGFR-3 and LMVD only in the HER2 type, and a positive correlation in HER2 and normal-like types with VEGFR-3 expression in tumor cells. In addition, there was a correlation between HER2 type, VEGF-C and VEGFR-3 expression in tumor cells and lymphatic endothelium, respectively, and LMVD.

CONCLUSION

Our results support a differential signature of lymphangiogenesis in different molecular types of breast cancer and these findings may have a direct impact on prognosis and therapeutic strategy of this disease.