Aberrant BLID expression is associated with breast cancer progression

In our previous study, we have found that BH3-like motif containing, cell death inducer (BLID) was a tumor suppressor in breast cancer, and its downregulation was correlated with both poor disease-free and overall survival. In the present study, we aimed to explore the possible role of BLID in breast cancer progression. We found that BLID was strongly expressed in all normal breast tissues, and it became lower and wreaker gradually in the progression from normal, UDH (usual ductal hyperplasia), ADH (atypical ductal hyperplasia), and DCIS (ductal carcinoma in situ) to breast cancer. Statistical analysis demonstrated significant different BLID expressions between proliferative and cancerous breast lesions. Our data suggested that loss of BLID may contribute to the progression of intraductal proliferation lesions to breast cancer. Our finding gives a new clue that BLID might be a potential indicator for progression of breast cancer in the future.     

Prognostic effects of abnormal DNA damage response protein expression in breast cancer

Breast Cancer Research and Treatment - We aimed to explore the expression of DNA damage response machinery proteins and their integrated prognostic value in different subgroups of breast cancer....     

Expression of proteins involved in DNA damage response in familial and sporadic breast cancer patients

Understanding the expression of proteins involved in DNA damage response could improve knowledge of the pathways that contribute to familial and sporadic breast cancer (BC). We aimed to assess the different roles of BRCA1, poly(ADP‐ribose) polymerase‐1 (PARP1), BRCT‐repeat inhibitor of hTERT expression (BRIT1) and novel SWItch 5 (SWI5) expression in 130 sporadic and 73 familial BC samples, by immunohistochemistry. In the sporadic group, negative nuclear BRCA1 (nBRCA1) expression was associated with positive PgR (p = 0.037). Negative association was found between nBRCA1 expression and HER2 (p = 0.001). In the familial group, nBRCA1 expression was associated with ER (p = 0.002). Reduced nBRCA1 expression was associated with higher histological grade and positive Ki67 both in sporadic (p = 0.0010, p = 0.047) and familial groups (p < 0.001, p = 0.001). Nuclear PARP1 (nPARP1) expression was associated with histological grade (p = 0.035) and positive PgR (p = 0.047) in sporadic cases. High cytoplasmic and low nuclear BRIT1 (cBRIT1 and nBRIT1) expression were associated with high histological grade in the familial group (p = 0.013, p = 0.025). Various statistical associations between the protein expressions were observed in the sporadic group, while in familial group only few associations were found. Univariate analyses showed that nPARP1 expression is able to discriminate between sporadic and familial tumors (OR 2.80, p = 0.002). Multivariate analyses proved that its overexpression is an independent factor associated with a high risk of sporadic tumor (OR 2.96, p = 0.017). Our findings indicate that nPARP1 expression is an independent factor for sporadic BCs and PARP1 inhibitors could be a promising therapy for different phenotypes.     

Aberrant cytoplasmic expression of the p16 protein in breast cancer is associated with accelerated tumour proliferation.

The p16 protein plays an important role in the transition of cells into the G1 phase of the cell cycle. We have studied the prevalence of p16 protein expression in breast carcinomas in a prospective series of 368 invasive and 52 non-invasive malignancies, as well as in 88 locally recurring tumours and three tumour cell lines. p16 protein expression was evaluated immunohistochemically on paraffin sections using monoclonal and polyclonal anti-p16 antibodies, and by immunoblotting of tumour cell suspensions. Tumour cell lines were also subjected to polymerase chain reaction-single strand polymorphism (PCR-SSCP) analysis and direct DNA sequencing. The results were compared with established prognostic parameters, DNA flow cytometry and p53 protein expression. In 33 (9%) invasive and two (4%) intraductal carcinomas, a cytoplasmic accumulation of the p16 protein was seen. These cases were characterized by poor histological grade of differentiation, loss of of oestrogen receptors and progesterone receptors and frequent overexpression of the p53 protein. In addition, breast carcinomas with aberrant p16 expression demonstrated a high proliferative activity, with median S-phase fractions 74% higher than in the control group and the median Ki67 fractions elevated to 75%. A genetic alteration of the p16 gene was not detectable in three analysed cell lines with cytoplasmic p16 expression applying PCR-SSCP and direct DNA sequencing. These results indicate that cytoplasmic accumulation of the p16 protein identifies a subset of highly malignant breast carcinomas with accelerated tumour proliferation and other unfavourable parameters in breast cancer. The described protein accumulation is apparently not caused by an alteration of the p16 gene.     

Aberrant DNA methylation but not mutation of CITED4 is associated with alteration of HIF-regulated genes in breast cancer

CBP/p300-interacting transactivator with ED-rich carboxy-terminal domain 4 (CITED4) inhibits HIF-1α transactivation by binding to CBP/p300. We hypothesised that either somatic mutation or hypermethylation of the CITED4 gene underlies CITED4 down-regulation and thus enhanced HIF-1α expression in some breast tumours. DNA sequencing was used to screen for somatic mutations. Methylation-sensitive high resolution melting was performed to identify CITED4 methylation. RT-qPCR was carried out to measure the expression of CITED4 and selected HIF downstream targets. HIF-1α and downstream gene expression was assessed with immunohistochemistry. No somatic mutations of CITED4 were identified in 10 tumour cell lines and 100 breast carcinomas. However, CITED4 promoter methylation was identified in 5/168 breast carcinomas (four infiltrating ductal carcinomas and one infiltrating lobular carcinoma) and in 3/10 breast cancer cell lines (MDA-MB-453, MDA-MB-231 and Hs578T). CITED4 mRNA expression in cell lines was inversely correlated with DNA methylation. CITED4 mRNA expression was significantly increased in all three cell lines after 5-aza-2-deoxycytidine (DAC) treatment. Treatment of the MDA-MB-231 cell line with DAC followed by hypoxia (0.1% O₂) resulted in down-regulation of expression of the HIF-1α downstream genes VEGFA and SLC2A1 (P = 0.0029). HIF-1α downstream SLC2A1 was decreased (P = 0.021) after CITED4 was re-expressed under hypoxia. Loss of expression of CITED4 in breast cancer may be due to DNA methylation but is unlikely to be due to mutation. Demethylation and histone modification can potentially reactivate CITED4 gene expression in some breast cancers and lead to changes in tumour behaviour. Strategies such as HDAC inhibitors may overcome this effect.     

ATM haplotypes and cellular response to DNA damage: association with breast cancer risk and clinical radiosensitivity

The ATM gene, mutated in the cancer-prone and radiation-sensitive syndrome ataxia-telangiectasia (AT), could predispose to breast cancer (BC) development and adverse radiotherapy responses. Sixteen ATM variants were genotyped in 254 BC cases, 70 of whom were adverse radiotherapy responders (RS-BC), and 312 control subjects and the ATM haplotypes were constructed. Constitutive ATM protein, cell survival, and the p53 response after exposure to ionizing radiation were compared in lymphoblastoid cell lines (LCLs) established from the BC cases, AT, and normal individuals. The tightly linked intronic ATM polymorphisms IVS22-77 T>C and IVS48 + 238 C>G, in the homozygote state were associated with increased BC risk [IVS22-77 CC versus TT odds ratio (OR), 1.67; 95% confidence interval (CI), 1.00-2.81], and in the heterozygote state with clinical radioprotection (IVS22-77 CT versus TT OR, 0.45; 95% CI, 0.24-0.85). Homozygote carriers of the G5557A variant were over-represented in RS-BC cases compared with non-RS-BC cases (OR, 6.76; 95% CI, 1.19-38.43). These three single nucleotide polymorphisms were associated with the three major ATM haplotypes present in >80% of the study population. BC LCLs treated with ionizing radiation exhibited an intermediate cell survival and p53 response between that of normal and AT LCLs, with the response in the RS-BC LCLs being more compromised than in the non-RS-BC LCLs. Our study suggests a general pattern of increased BC risk associated with carrying any one of the ATM variants studied, with a significant association being observed in individuals carrying variants on both ATM alleles (OR, 1.75; 95% CI, 1.09-2.81) and that ATM variants may impact on radiation sensitivity.     

DNA damage and breast cancer

Cancer is intimately related to the accumulation of DNA damage, and repair failures (including mutation prone repair and hyperactive repair systems). This article relates current clinical categories for breast cancer and their common DNA damage repair defects. Information is included on the potential for accumulation of DNA damage in the breast tissue of a woman during her lifetime and the role of DNA damage in breast cancer development. We then cover endogenous and exogenous sources of DNA damage, types of DNA damage repair and basic signal transduction pathways for three gene products involved in the DNA damage response system; namely BRCA1, BRIT1 and PARP-1. These genes are often considered tumor suppressors because of their roles in DNA damage response and some are under clinical investigation as likely sources for effective new drugs to treat breast cancers. Finally we discuss some of the problems of DNA damage repair systems in cancer and the conundrum of hyper-active repair systems which can introduce mutations and confer a survival advantage to certain types of cancer cells.     

Cyclin D1 expression is associated with poor prognostic features in estrogen receptor positive breast cancer

Cyclins D1 and E play an important role in breast carcinogenesis. High cyclin E expression is common in hormone receptor negative and high grade aggressive breast cancer, whereas cyclin D1 in hormone receptor positive and low grade breast cancer. Experimental data has suggested that cyclin D1 and E mediate cell proliferation by different mechanisms in estrogen receptor (ER) positive and negative breast cancer. To test this hypotheses in large breast cancer material and to clarify the histopathological correlations of cyclin E and D1, especially the association with proliferation, we analyzed cyclin E and D1 immunohistochemical expression on breast tumour microarrays consisting of 1348 invasive breast cancers. High cyclin D1 expression was associated with high grade (P < 0.0005), high cyclin A (P < 0.0005) and Ki67 (P < 0.0005) expression among ER positive but with low grade (P = 0.05) and low Ki67 (P = 0.01) expression among ER negative breast cancers. Cyclin E and D1 expression correlated positively in ER positive (P < 0.0005) but had a negative correlation in ER negative tumours (P = 0.004). Cyclin E associated with high grade among all tumours (P < 0.0005). In conclusion, the findings of this study show that cyclin D1 has separate roles, and proliferation is driven by different mechanisms in ER positive and negative breast cancers.     

Lipocalin 2 expression is associated with aggressive features of endometrial cancer

ABSTRACT: BACKGROUND: Increased expression of lipocalin 2 (LCN2) has been observed in several cancers. The aim of the present study was to investigate LCN2 in endometrial cancer in relation to clinicopathologic phenotype, angiogenesis, markers of epithelial-mesenchymal transition (EMT), and patient survival. METHODS: Immunohistochemical staining was performed using a human LCN2 antibody on a population-based series of endometrial cancer patients collected in Hordaland County (Norway) during 1981-1990 (n = 256). Patients were followed from the time of primary surgery until death or last follow-up in 2007. The median follow-up time for survivors was 17 years. Gene expression data from a prospectively collected endometrial cancer series (n = 76) and a publicly available endometrial cancer series (n = 111) was used for gene correlation studies. RESULTS: Expression of LCN2 protein, found in 49% of the cases, was associated with nonendometrioid histologic type (p = 0.001), nuclear grade 3 (p = 0.001), >50% solid tumor growth (p = 0.001), ER and PR negativity (p = 0.028 and 0.006), and positive EZH2 expression (p < 0.001). LCN2 expression was significantly associated with expression of VEGF-A (p = 0.021), although not with other angiogenesis markers examined (vascular proliferation index, glomeruloid microvascular proliferation, VEGF-C, VEGF-D or bFGF2 expression). Further, LCN2 was not associated with several EMT-related markers (Ecadherin, N-cadherin, P-cadherin, beta-catenin), nor with vascular invasion (tumor cells invading lymphatic or blood vessels). Notably, LCN2 was significantly associated with distant tumor recurrences, as well as with the S100A family of metastasis related genes. Patients with tumors showing no LCN2 expression had the best outcome with 81% 5-year survival, compared to 73% for intermediate and 38% for the small subgroup with strong LCN2 staining (p = 0.007). In multivariate analysis, LCN2 expression was an independent prognostic factor in addition to histologic grade and FIGO stage. CONCLUSION: Increased LCN2 expression is associated with aggressive features and poor prognosis in endometrial cancer.     

HCV nonstructural protein 4 is associated with aggressiveness features of breast cancer

Background

Hepatitis C virus (HCV) has the lymphotropic feature that is supposed to be the reason of related extrahepatic manifestation. HCV viral oncoproteins may participate in the regulation of some gene expression that has been implicated in tumorigenesis. Our aim is to evaluate the HCV-NS4 circulating levels in breast cancer (BC) and to investigate its relation with BC tumor aggressiveness.

Methods

This study was performed among 158 Egyptian women (120 with BC and 38 with benign breast diseases). ELISA was used for detection of anti-HCV antibodies, HCV-NS4, fibronectin, and CA 15-3.

Results

No association between HCV detection in this group of BC patients (27.5% in BC vs. 23.7% in breast benign diseases, P = 0.687). Among HCV-infected patients, the mean HCV-NS4 serum level in BC was significantly higher than benign group (61.7 μg/mL vs. 33.9 μg/mL, P = 0.0005). Fibronectin levels were higher (P = 0.014) in patients infected with HCV than noninfected BC patients. Elevated HCV-NS4 levels were associated with tumor severity features like large size, late stages, high grades, and infiltrated lymph nodes. The elevated levels of HCV-NS4 (> 40 μg/mL) yielded an estimated odds ratio (95% confidence intervals) of 2.5 (0.98–6.36), 1.2 (0.44–3.33), 1.9 (0.53–7.00), and 2.5 (0.87–7.33) for developing large size, late stages, high grades, and infiltrated lymph nodes, respectively. Interestingly, HCV-NS4 levels significantly correlated with other BC tumor marker like CA15-3 (r = 0.535; P = 0.0009) and fibronectin (r = 0.432; P < 0.0001).

Conclusions

HCV-NS4 appears to be associated with BC progression features. Oncologists treating such BC patients should consider HCV screening to enable the early identification and to prevent progression of the disease.

     

DNA repair genes PAXIP1 and TP53BP1 expression is associated with breast cancer prognosis

Despite remarkable advances in diagnosis, prognosis and treatment, advanced or recurrent breast tumors have limited therapeutic approaches. Many treatment strategies try to explore the limitations of DNA damage response (DDR) in tumor cells to selectively eliminate them. BRCT (BRCA1 C-terminal) domains are present in a superfamily of proteins involved in cell cycle checkpoints and the DDR. Tandem BRCT domains (tBRCT) represent a distinct class of these domains. We investigated the expression profile of 7 tBRCT genes (BARD1, BRCA1, LIG4, ECT2, MDC1, PAXIP1/PTIP and TP53BP1) in breast cancer specimens and observed a high correlation between PAXIP1 and TP53BP1 gene expression in tumor samples. Tumors with worse prognosis (tumor grade 3 and triple negative) showed reduced expression of tBRCT genes, notably, PAXIP1 and TP53BP1. Survival analyses data indicated that tumor status of both genes may impact prognosis. PAXIP1 and 53BP1 protein levels followed gene expression results, i.e., are intrinsically correlated, and also reduced in more advanced tumors. Evaluation of both genes in triple negative breast tumor samples which were characterized for their BRCA1 status showed that PAXIP1 is overexpressed in BRCA1 mutant tumors. Taken together our findings indicate that PAXIP1 status correlates with breast cancer staging, in a manner similar to what has been characterized for TP53BP1.     

Loss of Dicer expression is associated with breast cancer progression and recurrence

Dicer is a protein that plays a pivotal role in the final steps of the microRNA (miRNA) processing pathway, to produce mature miRNAs from their precursor molecules. The purpose of the current study was to assess the biological and prognostic value of Dicer protein expression in breast cancer (BC). Dicer protein expression was assessed immunohistochemically in two sets of BC: (1) full-face sections of selected BC series with distinct stages of tumour progression (normal, in situ (DCIS), primary invasive BC and nodal metastases) to evaluate its differential expression. (2) Tissue microarray comprising a large and well-characterised series of unselected clinically annotated invasive BC (n?=?1,174) to investigate its correlation with clinicopathological features and patient outcome. A gradual loss of Dicer protein expression was observed in malignant compared to normal breast tissues, with the loss being the least in DCIS and most prominent in metastatic malignant cells. In invasive BC, loss of Dicer expression was associated with features of aggressive behaviour including higher histological grade, loss of hormone receptor and BRCA1 protein expression and with shorter disease-free survival (DFS). Dicer expression was an independent predictor of recurrence in the aggressive HER2-positive subgroup. Moreover, loss of Dicer was predictive of better response to chemotherapy and to endocrine therapy. This study provides evidence that Dicer protein plays a role in human BC progression and behaviour, and assessment of its expression could provide prognostic information in BC including the HER2-positive class.     

Aberrant methylation of imprinted genes is associated with negative hormone receptor status in invasive breast cancer

Epigenetic regulation of imprinted genes enables monoallelic expression according to parental origin, and its disruption is implicated in many cancers and developmental disorders. The expression of hormone receptors is significant in breast cancer because they are indicators of cancer cell growth rate and determine response to endocrine therapies. We investigated the frequency of aberrant events and variation in DNA methylation at nine imprinted sites in invasive breast cancer and examined the association with estrogen and progesterone receptor status. Breast tissue and blood from patients with invasive breast cancer (n = 38) and benign breast disease (n = 30) were compared with those from healthy individuals (n = 36), matched with the cancer patients by age at diagnosis, ethnicity, body mass index, menopausal status and familial history of cancer. DNA methylation and allele‐specific expression were analyzed by pyrosequencing. Tumor‐specific methylation changes at IGF2 DMR2 were observed in 59% of cancer patients, IGF2 DMR0 in 38%, DIRAS3 DMR in 36%, GRB10 ICR in 23%, PEG3 DMR in 21%, MEST ICR in 19%, H19 ICR in 18%, KvDMR in 8% and SNRPN/SNURF ICR in 4%. Variation in methylation was significantly greater in breast tissue from cancer patients compared with that in healthy individuals and benign breast disease. Aberrant methylation of three or more sites was significantly associated with negative estrogen‐alpha (Fisher's exact test, p = 0.02) and progesterone‐A (p = 0.02) receptor status. Aberrant events and increased variation in imprinted gene DNA methylation, therefore, seem to be frequent in invasive breast cancer and are associated with negative estrogen and progesterone receptor status, without loss of monoallelic expression.