Centralised multidisciplinary management of breast cancer occurs in KwaZulu-Natal, South Africa and requires a diagnostic and staging pathway at the referring hospital. Delays in this pathway are unknown. This study, conducted at a referring hospital, R K Khan (RKK), quantifies and analyses these delays. A retrospective folder review included all patients with breast cancer diagnosed at RKK from January 2008 to January 2009. Data extraction included demographic data, time to diagnosis and initial staging using a standardised datasheet. Specific care steps were identified, namely delays to initial imaging with mammography, pathology confirmation, staging workup and eventual referral to a centralised breast clinic.

No description available.

The authors report a case of fine‐needle aspiration (FNA) of a breast mass in a 36‐year‐old woman with previous history of lumpectomy and therapeutic radiation for breast carcinoma. The changes seen were interpreted as recurrent carcinoma, while subsequent biopsy showed only radiation changes. Radiation‐induced changes in breast tissue are a potential diagnostic pitfall. The characteristic cytopathologic changes and their differential diagnosis are discussed.

No description available.

In 2016, there were 250,000 new cases of invasive cancer and 60,000 of ductal carcinoma in situ. Mammograms are used to screen for cases of disease, but the literature shows that mammograms are highly dependent on patient characteristics and do not majorly impact mortality rates from invasive cancer. Additionally, they are prone to false-positives, false-negatives, and overdiagnosis in cases of in situ cancer, with overdiagnosis exposing patients to the side effects of treatment. Better screening tests are needed, and a potential solution can be to extend molecular screening methods often used in advanced stage 1 and higher cancers to stage 0 ductal carcinoma in situ cases. This new test would prevent overdiagnosis, be more accurate, and prevent unnecessary screening as well as be in line with the future of cancer care in the US.

Indiana University-Purdue University Indianapolis (IUPUI) / 2021-11-30

The breast tumor suppressor hCLCA2 is a putative chloride regulator that is expressed in normal breast epithelial cells and frequently down-regulated in breast cancers. The first CLCA protein was described as a calcium-activated, plasma-membrane chloride channel having four or five transmembrane pass structure that could form a channel pore. However, CLCA topology is inconsistent with chloride channel function. We showed that hCLCA2 itself is unlikely to form a channel as it has only a single transmembrane segment with a short cytoplasmic tail and is mostly extracellular. Moreover, the N-terminal 109-kDa ectodomain is cleaved at the cell surface and shed into the medium while the 35-kDa C-terminal product is retained by the cell membrane. The general goal of my project was to study the function of this novel protein and its role in breast cancer. In addition to its role in chloride regulation, hCLCA2 behaves as a tumor suppressor gene that is frequently down-regulated in breast cancer. We previously demonstrated that murine homologs of hCLCA2 are transcriptionally induced during mammary involution, when the gland shuts down and 80% of the mammary epithelial cells die by apoptosis. In cell culture, conditions that cause G1 arrest such as contact inhibition and depriving cells of growth factors and anchorage induced these genes. Therefore, one of the goals of this project was to find if this is true of hCLCA2 in human breast epithelial cells. We found that hCLCA2 was induced by the above mentioned stresses and by pharmacological blockage of cell survival signaling. In addition, we found that DNA-damaging agents doxorubicin and aphidicolin potently induced hCLCA2 in p53-positive cell lines such as MCF-7 but not in p53-deficient cells such as MDA-MB231. An adenovirus encoding p53 induced hCLCA2 expression in a broad spectrum of breast cancer cell lines while a control virus did not, suggesting that hCLCA2 is a p53-inducible gene. To further test the hypothesis, we performed chromatin immunoprecipitation (ChIP) to determine whether p53 bound to the hCLCA2 promoter. This analysis showed that p53 binds directly to the hCLCA2 promoter between -157 and -359bp upstream of the translation initiation site. This segment was required for the p53-dependent expression of an hCLCA2-luciferase fusion gene. Point mutation of the p53 consensus binding motif abolished this induction. Induction of hCLCA2 in MCF-7 cells by doxorubicin was inhibited by p53 knockdown and by p53 inhibitor pifithrin, indicating that p53 activates the endogenous hCLCA2 promoter in response to DNA damage. An adenovirus encoding hCLCA2 induced a cell cycle lag in G0/G1 phase, decreased intracellular pH from 7.49 to 6.7, caused Bax and Bad translocation to the mitochondria, activated caspases, induced PARP cleavage, and promoted apoptosis. Conversely, hCLCA2 knockdown enhanced proliferation of epithelial MCF10A cells and reduced sensitivity to doxorubicin. These results reveal the molecular mechanism of hCLCA2 induction and downstream events that may provide protection from tumorigenesis. Epithelial cells acquire mesenchymal characteristics by undergoing phenotypic and genotypic changes during cancer progression. An early step in the epithelial to mesenchymal transition (EMT) is the disruption of intercellular connections due to loss of epithelial cadherins. We find that expression of tumor suppressor hCLCA2 is strongly associated with epithelial differentiation and that induction of EMT by mesenchymal transcription factors represses its expression. Moreover, we found that knockdown of hCLCA2 by RNA interference results in disruption of cell-cell junctions by downregulating E-cadherin. This also imparts invasiveness and anoikis-resistance to epithelial cells but is insufficient to induce full EMT. However, activation of Ras oncogene in combination with hCLCA2 knockdown is sufficient to induce full EMT in vitro. These findings indicate that, like E-cadherin, hCLCA2 is required for epithelial differentiation and that its loss during tumor progression may contribute to metastasis.

No description available.

No description available.

Triple negative breast cancer (TNBC) is an aggressive subtype of the disease with dismal clinical outcome. Immune checkpoint blockade (ICB), which blocks inhibitory pathways on T cells, has surged to the forefront of cancer therapy with clinical success in a variety of cancer types. However, ICB for TNBC only benefits 10-20% of patients. Thus, a deeper understanding of the immune landscape in TNBC is required to develop efficacious therapies and delineate prognostic biomarkers of disease. We have developed combination therapy platforms that sensitize TNBC tumors to ICB. Using a clinical chemotherapy (FEC) combined with oncolytic virotherapy (oHSV-1) we show enhanced tumor-infiltrating lymphocytes (TILs), upregulation of B cell receptor signaling pathways, suppression of myeloid-derived suppressor cells (MDSCs) and improved survival. In vivo depletion studies revealed that B cells were required to achieve cures with treatment. Furthermore, the absence of B cells resulted in the expansion of MDSCs. This crucial finding of the importance of B cells for mediation and downregulation of MDSCs is a novel and significant contribution to the field. RNA sequencing revealed that two of the top upregulated genes in mice treated with FEC + oHSV-1 were S100A8 and S100A9, calcium binding proteins highly expressed in myeloid cells. These genes have controversial findings in the literature with both pro- and antitumorigenic functions being reported. Investigation of data from the Cancer Genome Atlas revealed that high levels of S100A8 and S100A9 correlate with improved prognostic outcomes in breast cancer patients. In line with the clinical data, our data suggests that increased levels of S100A8 and S100A9 results in improved responses to immunotherapy treatments and that this increased expression is involved in macrophage-mediated epigenetic reprogramming of the tumor microenvironment. Our second therapeutic platform used a radiolabeled biomolecule containing the beta-emitting radioisotope, lutetium-177. We found that two doses of radiotherapy, combined with ICB improved overall survival in murine TNBC tumors, increased TILs and suppressed circulating MDSCs. These findings offer insight into the newly explored field of combination radioimmunotherapy and again highlight the importance of suppressing MDSCs to alleviate tumor immunosuppression. / Thesis / Doctor of Philosophy (PhD) / Triple-negative breast cancer (TNBC) has poor prognostic outcomes due to lack of expression of targets for therapy. As such, patients routinely undergo aggressive treatment regimens with many harsh side effects, including high levels of toxicity. Immunotherapy, a form of therapy that boosts the immune system to fight cancer cells, has gained increasing prominence largely due to its safety and low toxicity to the patient. In the work within this dissertation, we have developed therapeutic platforms and studied them in a murine model of TNBC. The completed studies show the use of clinical therapies, in combination with immunotherapy and investigate the fundamental biology associated with therapeutic outcomes. These findings contribute knowledge to progress clinical regimens for TNBC patients as well as to better identify patients that will respond to therapy. Although this proposal is specific to breast cancer, the underlying concepts can be applied to many other forms of cancer.