Background: Mammographic density (MD) for age and BMI is a strong risk factor (up to a 6 fold increase across extreme quantiles) for breast cancer. More than 60% of MD variation is estimated to be due to heritable (genetic) factors. Taking two different approaches, this work aimed to determine some of these genetic factors. The recently identified common genetic variants associated with small gradients in breast cancer risk and candidate common genetic variants identified using a genome wide association study (GWAS) of MD extremes were tested for an association with MD. / Methods: Germline DNA extracted from peripheral blood samples from 497 monozygotic (MZ) and 330 dizygotic (DZ) twin pairs, and 634 of their sisters from 903 families were genotyped for 22 independent variants (12 from associations with breast cancer and 10 from GWAS of MD extremes). Mammographic dense area, percent dense area and non-dense area were measured by three observers using a computer thresholding technique. Associations with MD measures adjusted for age, BMI and other determinants were estimated: (a) cross-sectionally using a multivariate normal model for pedigree analysis (P-values reported by Px), and (b) between-sibships and (c) within-sibships using orthogonal transformations of outcomes and exposures. A combined test of association (P-values reported by Pc) was derived using the independent estimates from (b) and (c). The distributions of P-values across variants were tested for a deviation from the uniform distribution (P-values reported by Pu). / Results: For the breast cancer associated common genetic variants tested, for dense area and percent dense area, the distributions of Pc-values deviated from the uniform distribution (both Pu<0.007), providing strong evidence that at least one genetic variant is associated with these MD measures. Consistent with their breast cancer associations, rs3817198 (LSP1) and rs13281615 (8q) were associated with dense area and percent dense area (all Px and Pc<0.05), and rs889312 (MAP3K1), rs2107425 (H19) and rs17468277 (CASP8) were marginally associated with dense area (some Px or Pc <0.05). For the candidate genetic variants from the GWAS of MD extremes the distributions of Pc-values deviated from the uniform distribution for dense area and percent dense area (Pu=0.07 and 0.009). One variant, rs10827227 (NRP1) showed strong evidence for an association with both dense area and percent dense area (Pc<0.009). For both approach, all associations were independent of menopausal status. / Conclusion: At least two common breast cancer susceptibility variants and one common variant identified through a GWAS for MD extremes were associated with MD measures that predict breast cancer. Together these variants explain about 1% of the variation in MD.

Background: Axillary lymph node dissection as routine part of breast cancer treatment has been questioned in relation to the balance between benefits and morbidity. The purpose of this study is to determine the association of tumor size, age and histological grade with axillary lymph node metastasis, to determine if some patients could be exempted from axillary dissection. Methods: The data are derived from BreastScreen NSW, the government sponsored population-based breast screening program. In New South Wales (NSW) Australia between 1995 and 2002, 7,221 patients with invasive breast carcinoma were diagnosed and 5,290 patients were eligible for this study. The relationship between incidence of positive axillary lymph nodes and three study factors (tumor size, age and histological grade) was investigated by univariate and multivariate analysis. Logistic regression models were used to predict probability of axillary metastases. Results: The incidence of axillary lymph node metastases was 28.6% (95% CI: 27.4%- 29.8%). Univariate analysis showed that age, tumor size and histological grade were significant predictors of axillary lymph node metastases (p<0.0001). Multivariate analysis identified age, tumor size and histological grade remained as independent predictors (p<0.0001). From multivariate analysis, patients with T1a (Less than or equal to 5mm) and grade I tumors regardless of age had 5.2% (95% CI: 1.2%- 9.3%) frequency of node metastases. Patients 70 years or older with grade I, T1a and T1b (6-10mm) tumors had 4.9% (95% CI: 3.2%- 7.5%) and 6.6% (95% CI: 5.3%-8.3%) predicted frequency of node metastases. Conclusions: Tumor size, age and histological grade are predictors of axillary lymph node metastases. Routine axillary lymph node dissection could be avoided in some patient groups with a low frequency of involved lymph nodes if the benefits are considered to exceed the risks.

Title page, table of contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / Metastasis is a multi-step process during which cancer cells disseminate from the primary tumour and establish secondary tumours in distant sites. The mechanisms for organ-specific metastasis are poorly understood, although recent findings suggest the role of a number of chemokine receptors on various cancer cells such as breast CXCR4 as well as CCR7, are a protein-coupled chemokine receptor (apCR) that have proven to be of considerable biological significance, since their expression has been shown on various malignant breast cancer cell lines, tumours and metastases. In this study the expression and function of CXCR4 and CCR7 was examined in a range of human breast cancer cell lines covering a spectrum of malignant and non-malignant phenotypes. The data revealed that while surface levels of CXCR4 and CCR7 were uniform across the entire panel of breast cancer cell lines, only highly invasive cells, metastatic in immunocompromised mice, expressed functional chemokine receptors. Moreover, multiple signalling pathways downstream of a proteins in the highly invasive cells were found to be activated however chemokine treatment failed to activate any of the downstream kinase cascades examined in non-invasive cell lines. For the first time, to the best of our knowledge, chemokine receptor function was demonstrated to be subject to complex and tightly-controlled regulation in epithelial breast cancer cells via differential a protein-receptor complex formation and that this regulation might significantly contribute to the transition from non-metastatic to malignant tumours. Finally, the role of CXCR4 and CCR7 during breast cancer metastasis was verified using a humanised breast cancer metastasis mouse modeL By modulating the expression of chemokine receptors using siRNA-mediated knockdown, metastasis of breast cancer cells to the lungs of SCID mice was dramatically inhibited. In summary, the data point to distinct molecular mechanisms of chemokine receptor activation used by transformed invasive breast epithelial cells which leads to the metastatic spread of these cancer cells to distant sites. Improved understanding of the role of chemokine receptor/ligand interaction in metastasis may lead to novel approaches in the treatment and management of breast cancer as well as other solid tumour malignancies. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1289342 / Thesis (Ph.D.) -- University of Adelaide, School of Molecular and Biomedical Science, 2007

A growing body of work implicates chemokines and their receptors in the progression of various types of cancer, including breast cancer. However, as potent chemotactic factors for leukocytes, chemokines also have the potential to enhance anti-cancer immunity. Evidence suggests that the chemokine CXCL12 and its receptors may be important in a number of aspects of breast cancer progression and site-specific metastasis. Another chemokine, CXCL16, has been identified as a specific chemotactic factor for Type Ipolarised T lymphocytes, which are major effectors of cell-mediated immunity and hence efficacious anti-tumour immune responses. The aim of this study, therefore, was to further elucidate the roles of CXCL12 and CXCL16 in breast cancer development and metastasis. To achieve this, wild-type CXCL12 and CXCL16 and antagonists of CXCL12 and CXCL16 activity, CXCL12[subscript](P2G) and CXCL16[subscript](9-220) respectively, were overexpressed in the 4T1.2 mouse model of breast carcinoma. Overexpression of wild-type CXCL12 potently inhibited both primary tumour growth and metastasis in this model. This was attributed to the induction of an anti-tumour response dependent, in part, on T cells, interferon-g and the cytotoxic mediators perforin and TRAIL. This response was characterised by increased numbers of CD11c⁺ cells in the tumour-draining lymph nodes and enhanced cytolytic activity of lymph node-derived effector cells against tumour cells. Unexpectedly, CXCL12[subscript](P2G) inhibited metastasis of tumour cells to the lungs of tumour-bearing mice, without affecting primary tumour growth. Intravenous injection of tumour cells revealed that CXCL12[subscript](P2G) expression could block metastatic steps occurring post tumour cell escape from the primary tumour, though a role for CXCL12([subscript](P2G) at earlier metastatic steps could not be ruled out. Further work is needed to clarify the precise stages of metastasis at which CXCL12[subscript](P2G) exerts its effects. No obvious effects on primary breast tumour growth were observed when CXCL16 or CXCL16([subscript](9-220) were overexpressed in tumour cells. Interestingly, CXCL16[subscript](9-220) expression inhibited experimental metastasis but not spontaneous metastasis. The findings of this study begin to shed light on the roles of CXCL12 and CXCL16 in breast cancer progression and also highlight the potential therapeutic applications of CXCL12, CXCL16 and/or their antagonists in the treatment of breast cancer and breast cancer metastasis. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1297662 / Thesis (Ph.D.) -- University of Adelaide, School of Molecular and Biomedical Science, 2007

Thesis (Ph. D.)--University of Hong Kong, 2008. / Also available in print.

Thesis (Honors)--College of William and Mary, 2008. / Includes bibliographical references (leaves 76-81). Also available via the World Wide Web.

Thesis (Ph. D.)--University of Hong Kong, 2008. / Also available online.

Thesis (M.S.)--Youngstown State University, 1997. / Includes bibliographical references (leaf 94).

Thesis (M.S.)--Ball State University, 2009. / Title from PDF t.p. (viewed on Mar. 17, 2010). "December 2008." Research paper (M.S.), 3 hrs. Includes bibliographical references (p. 52-55).

<b>Background:</b> Aryl Hydrocarbon Receptor Interacting Protein-Like 1 (AIPL1) interacts with NUB1 and restricts the entry of NUB1 protein into the nucleus. The interferon-induced NEDD8 ultimate buster (NUB1) protein causes degradation of neddylated and FAT10ylated proteins through the ubiquitin proteasome system. We observed AIPL1 were frequently down-regulated in various cancers compared to normal tissues. The mechanistic roles of AIPL1 and NUB1 protein in cancer cell cycle regulation remain unexplored. <b>Results:</b> Meta-analysis of cancer databases revealed that expression transcripts of chaperones, including AIPL1, were down-regulated in lung, pancreatic cancer and breast cancer relative to the adjacent normal tissues. Opposite levels of both AIPL1 and NUB1 transcripts were observed in the breast cancer. So it triggers the in vitro experiments using breast cancer cells. METABRIC breast cancer clinical cohort highlighted that patients with low NUB1 transcripts had poor survival in the ER-negative subgroup (but not in ER-positive) of breast cancer patients: hazard ratio (HR)=0.66, 95% confidence interval (CI)=0.5-0.87, p=0.003 and triple negative subgroup of breast cancer patients: HR=0.67, 95% CI=0.47-0.96, p=0.028. NUB1 silencing significantly inhibits in vitro cell growth in MDA-MB-231 and MCF7 under hypoxia. AIPL1 protein forms multimers in cancer cells. NUB1 protein moved into the nucleus in hypoxia (0.1% O2 48hrs) with final confluency at 80-90%. p21 (marker of senescence) &amp; p27 (marker of cell cycle arrest) accumulated in NUB1-silent MDA-MB-231 and RCC4 cells. It suggested that low NUB1 nuclear localisation in hypoxia cause cancer cell cycle arrest. In MDA-MB-231 cell, upon hypoxia, neddylation inhibitor (MLN4924) treated and siNUB1 transfected cells showed decreased CUL1 and further accumulated p21 &amp; p27. The evidence suggested lower neddylated CUL1 and reduced NUB1 cooperatively stabilise p21 and p27 as the substrate of CUL1-ubiquitin ligase. The neddylation inhibitor MLN4924 treated and NUB1 knockdown group exhibited more cells in sub-G1 stage as compared to the control group. In connection to higher p21/p27, it is associated with prolonged arrested cellular aging with depletion. After silencing of NUB1, the increases in cell death of cancer cells upon hypoxia happen through the neddylation-dependent CUL1-p27-p21 and CUL2-VHL axis. We then demonstrated that HIF1&alpha; protein could be both neddylated and FAT10ylated upon reoxygenation. In a tissue microarray study of breast cancer, lower cytoplasmic expression (n=57) had worse overall survival than higher cytoplasmic expression (n=57): HR=1.779, 95% CI=1.006-3.346, p=0.048. <b>Conclusions:</b> AIPL1 and NUB1 proteins exert a role in cell cycle regulation in breast cancer. Low cytoplasmic NUB1 levels are observed in the G₁-S transition of cancer cells. NUB1 depletion causes G₀/G₁ phase arrest due to CUL1 and CUL2 ubiquitin E3 ligase-dependent pathways.