Examples Of Breast Cancer Research Papers Ln - Essay Writing Help

 

examples of breast cancer research papers ln

Purpose. The purpose of this paper is to describe the content for the Asian American Network for Cancer Awareness Research and Training (AANCART) with respect to Asian American demographic characteristics and their cancer burden, highlights of accomplishments in various AANCART regions, aspirations for AANCART, and an interim assessment of AANCART’s activities to miccans.cf: Moon S Chen. examples of breast cancer research papers ln. habilitation thesis bibtex; help me with my book report bit of difference between the specic topic in this case would be significantly correlated student and dissertation research are frequently used as publicity, typically for a long tradition in biblical exegesis and scholarship, although as a. NCI is the nation's leader in cancer research. Learn more about NCI's cancer research areas, key initiatives, progress made in cancer research, and resources for researchers like research tools, specimens and data.


Risk determination and prevention of breast cancer | Breast Cancer Research | Full Text


Breast cancer is a complex and heterogeneous disease. Gene expression profiling has contributed significantly to our understanding of this heterogeneity at a molecular level, refining taxonomy based on simple measures such as histological type, tumour grade, lymph node status and the presence of predictive markers like oestrogen receptor and human epidermal growth factor receptor 2 HER2 to a more sophisticated classification comprising luminal A, luminal B, basal-like, HER2-positive and normal subgroups.

In the laboratory, breast cancer is often modelled using established cell lines. In the present review we discuss some of the issues surrounding the use of breast cancer cell lines as experimental models, in light of these revised clinical classifications, and put forward suggestions for improving their use in translational breast cancer research.

The first human cell line was established in a Baltimore laboratory over 50 years ago by George Gey [ 1 ]. This cell line was HeLa - named after Henrietta Lacks, the lady from whom the cell line was derived, who had cervical carcinoma, examples of breast cancer research papers ln. Gey's vision paved the way for cell culture as we know it today, allowing its widespread development into an important experimental tool in cancer research.

One of the major benefits of using cultured cell lines in cancer research is that they offer an infinite supply of a relatively homogeneous cell population that is capable of self-replication in standard cell culture medium.

The first breast cancer cell line to be established was BT in [ 2 ]. It was another 20 years, however, examples of breast cancer research papers ln, before establishing breast cancer cell lines became more widespread, including the MD Anderson series [ 3 ] and what still remains the most commonly used breast cancer cell line in the world, MCF-7 established in at the Michigan Cancer Foundation [ 4 ].

The popularity of MCF-7 is largely due to its exquisite hormone sensitivity through expression of oestrogen receptor ERmaking it an ideal model to study hormone response [ 5 ]. Despite these early accomplishments, relatively few breast cancer cell lines have been established in the more recent past, mainly because of difficulties in culturing homogeneous populations without significant stromal contamination and, at least in the United Kingdom, examples of breast cancer research papers ln due to rigorous ethical regulations surrounding obtaining human tissue for research [ 6 ].

Successes include the SUM series of 10 cell lines derived from either breast primary tumours, pleural effusions or various metastatic sites in individual patients [ 7 ]. These cell lines are now widely available through commercial cell banks.

Long before the advent of modern molecular profiling techniques, histopathologists recognised that breast cancer was heterogeneous through morphological observations. Classification was based on the following measures: histological type, examples of breast cancer research papers ln, tumour grade, lymph node status and the presence of predictive markers such as ER and, more recently, human epidermal growth factor receptor 2 HER2. Molecular characteristics of these sub-types are summarised in Table 1.

Each subtype has different prognosis and treatment response [ 10 ]. Because ER is a therapeutic target, the luminal A and luminal B subtypes are amenable to hormone therapy. Similarly the HER2 group are potential candidates for trasuszumab therapy. In the current absence of expression of a recognised therapeutic target, basal tumours are difficult to treat, more biologically aggressive and often have examples of breast cancer research papers ln poor prognosis.

Although there are similarities in the basal and triple-negative phenotypes, the terms are not strictly interchangeable; as outlined in a recent review, there is still no unifying definition for basal cancers and, while triple-negative enriches for basal breast cancer, the phenotypes are not identical [ 11 ].

More recently the claudin-low subtype was described by interrogating established human and murine datasets [ 12 ].

Our group previously highlighted the pros and cons of using cell lines as in vitro models of breast cancer [ 14 ]. Although questions have been raised over how representative immortalised cell lines are of human breast cancer [ 15 ], when used in the right way these remain powerful experimental tools and in many instances the information derived from these has translated into clinical benefit.

With the different molecular classifications of breast cancer now firmly established, researchers have turned their attention to breast cancer cell lines to determine whether the molecular profiles observed in breast carcinomas are reflected in cell line models of the disease.

A comprehensive evaluation of breast cancer cell lines by Lacroix and Leclercq, conducted before molecular profiling of breast cancer was widespread, concluded that while breast cancer cell lines have advanced our understanding of breast cancer biology, gaps still remained in terms of how representative these are [ 20 ] - in particular, the extent to which a single cell line can mirror the heterogeneity associated with clinical samples, the limited coverage of specialised histopathological types and whether the phenotype of a breast tumour in vivo is maintained in cell culture.

This conclusion was reinforced in a breast cancer gap analysis [ 21 ]. Application of sophisticated transcriptional profiling to breast cancer cell lines using various platforms has gone some way to address these issues. In general, these studies have shown that the luminal, basal, HER2 and claudin-low clusters identified in breast tumours can easily be distinguished in breast cancer cell lines Table 1 [ 1322 — 26 ].

These cell lines examples of breast cancer research papers ln good opportunities for the further study of this phenotype, which will enhance our understanding of its biology. In an estimate of therapeutic response, luminal breast cancer cell lines preferentially responded to the AKT inhibitor GSK and the phosphoinositide 3-kinase inhibitor GSK, while proliferation of basal cell lines was selectively inhibited by the MEK protein kinase inhibitor GSK [ 27 ].

The response to trastuzumab, an antibody that selectively binds HER2, was evaluated in a panel of nine breast cancer cell lines with known HER2 amplification, but only three out of nine cell lines showed an unequivocal response [ 22 ]. These studies indicate the need for a more rational approach for screening potential new breast cancer therapies by taking into account the different subgroups and recognising that response may not always be identical even within subgroups.

Stem cells are characterised by their ability to yield new tumours when xenografted into immunodeficient mice. Increasingly demonstrated is that very small numbers of CSCs often described as tumour-initiating cells exist within human breast cancer cell lines [ 3132 ]. There are clearly many advantages to working with CSCs derived from cell lines as they may be good models examples of breast cancer research papers ln further understand stem cell biology and develop CSC-specific therapeutic targets.

Two major obstacles need to be overcome, however, before these can be developed for routine use: CSCs are very much in the minority within a given tumour population, and CSCs have extremely slow population-doubling times. Improved enrichment methods are required to provide sufficient numbers of CSCs to conduct these types of studies, and their slow proliferation rates are challenging when it comes to experimentally testing potential new therapeutics.

Complex examples of breast cancer research papers ln that exist between cells in vivo are lost when cell lines are cultured on plastic in two dimensions, yet two-dimensional culture still remains the most favoured mechanism for in vitro studies in breast cancer research, examples of breast cancer research papers ln.

In addition, cell lines are often sensitive to culture conditions - particularly the inclusion of growth factors that can sometimes alter the cell phenotype, resulting in inappropriate pathway activation or differentiation. For example, when epidermal growth factor - a common component in media designed to culture breast myoepithelial cells - is included in luminal epithelial cell culture, this can induce loss of expression of E-cadherin characteristic of epithelial to mesenchymal transition and the cells exhibit a more motile phenotype [ 33 ] Culture under inappropriate conditions can also dramatically influence cell morphology, examples of breast cancer research papers ln, cell-cell and cell-matrix interactions, cell polarity and differentiation [ 3435 ], as well as altering signalling cascades and gene expression [ 36 ].

Identification of the most appropriate conditions to maintain the desired cell phenotype is thus a critical issue. As well as considering the molecular profiles of breast cancer cell lines, we also need to look beyond simple two-dimensional breast cancer models.

There has thus been a shift in growing cells in more physiologically relevant three-dimensional systems with the increased complexity of including multiple cell types [ 3437 ]. As highlighted by Kenny and colleagues, cell morphology in three dimensions is different from that observed in two dimensions on tissue culture plastic [ 38 ]. In two dimensions, luminal-like epithelial cells demonstrated the classic cobblestone morphology and expression of cell-cell adhesion molecules such as E-cadherin, whereas basal epithelial cells displayed a more elongated and spiky appearance and expressed markers of epithelial-mesenchymal transition such as vimentin.

In contrast, cell lines grown in three-dimensional culture showed four different morphologies: round, mass, grape-like and stellate [ 38 ]. MCF12A normal mammary epithelial cells formed round polarised acini-like structures similar to those seen in normal human breast tissue. Examples of the type of cell morphology we routinely observe when luminal A and HER2-positive cells are grown in two-dimensional and three-dimensional cultures are shown in Figure 1 and present close parallels with the study by Kenny and colleagues [ 38 ].

Cell morphology of cell lines grown in two-dimensional and three-dimensional cultures. T47D cells demonstrate a tightly cohesive cobblestone appearance, whereas MDA-MB cells have an elongated and spindly appearance. T47D cells form tightly cohesive mass structures displaying robust cell-cell adhesions, whereas MDA-MB cells form loosely cohesive grape-like structures consistent with morphology observed by Kenny and colleagues [ 38 ].

Functional three-dimensional studies have led to a greater understanding of normal breast structure and development; for example, by defining a role for laminin V and desmogleins in epithelial cell polarity and maintenance of normal tissue architecture [ 353940 ]. With the role of the stroma in regulating breast cancer behaviour receiving increased attention [ 42 — 44 ] and the recent recognition that basal and luminal breast examples of breast cancer research papers ln behave very differently when co-cultured with stromal fibroblasts [ 45 ], other three-dimensional breast cancer models have incorporated stromal cells such as fibroblasts [ 46 ], macrophages [ 47 ] and endothelial cells [ 48 ].

Increasing the complexity of these models is not without its problems, identification of individual cell populations within multicellular structures is particularly challenging and difficulties in quantifying structures formed remain an issue, although computer-based methods of morphological analysis show potential [ 49 ]. A recent study has successfully modelled preinvasive ductal carcinoma in situ by co-culturing tumour cells with myoepithelial cells, observing ductal carcinoma in situ structures similar to those seen in clinical specimens [ 46 ].

Further addition of tumour-associated fibroblasts resulted in tumour cell invasion and morphology reminiscent of invasive carcinoma [ 46 ]. Although this is a big advance towards modelling the stages of breast cancer progression, the gold standard that is yet to be achieved is to enable co-evolution of tumour and stromal components in vitro. These complex multicellular three-dimensional cultures are not just a tool for understanding disease progression, but may have important implications in drug screening.

This was highlighted recently by Pickl and Ries [ 50 ], who demonstrated a significantly higher response of SKBR3 cells to trastuzumab when the cells were cultured in three dimensions compared with cells cultured in two dimensions. Three-dimensional models may thus become a more widespread tool for research and examples of breast cancer research papers ln screening, and while these models are technically challenging to establish, they are in the long term much more biologically relevant models for studying the disease in vitro, examples of breast cancer research papers ln.

While existing three-dimensional breast cancer models are moving towards the addition of some of the cellular components found within the complex breast tumour microenvironment [ 4651 ], inclusion of CSCs has thus far been overlooked. Addition of stem cells derived from the various cell types within the breast tumour microenvironment may augment these in vitro three-dimensional studies.

With the difficulties in enriching for CSCs and their slow proliferation rates, this is not a trivial task. Nevertheless, more complex heterotypic models are required to fully model the in vivo cellular environment - a systems biology approach is needed to tackle this. The choice of cell culture medium becomes increasingly relevant, with complex cultures containing multiple cell types where media for one cell type may influence the phenotype of the co-cultured cell population.

This in itself may present problems; having to rely on a single type of media to support cell types that may have quite different media requirements is challenging and emphasises the need for correct controls and robust standardisation of methodology.

Whilst xenograft models provide a whole organism environment for tumour growth, these too have limitations. Experiments are usually performed in immunocompromised mice, which can impact on tumour formation and progression.

The site of implantation is an important consideration, with injections into the mammary fat pad considered more physiologically relevant than subcutaneous injections even though the mouse and human mammary glands have quite different structures. Another confounding variable is the distinct difference between the stroma of human and mouse mammary tissue, which casts doubt on the relevance of xenograft models [ 52 ]. As discussed above, the stroma is now recognised to influence breast tumour cells.

The differing biology of mouse and human stroma together with reports of spontaneous transformation of mouse stroma by human breast tumour xenografts, resulting in hybrid mouse-human nuclei within the xenograft [ 53 ], raise further concerns. Several groups have tried to overcome this by co-injecting human fibroblasts with cancer cell lines [ 5455 ], but this does not allow for co-evolution of tumour and stroma that would happen during cancer development.

Of the cell lines commonly incorporated into xenograft models, ER-positive luminal A cell lines such as MCF-7 and T47D will only form tumours in the presence of oestrogen and, unsurprisingly, growth can be inhibited by anti-oestrogen therapy. An unexpected finding with xenograft models is the limited ability of tumours to invade and metastasise, particularly given the often metastatic origin of cell lines reviewed in [ 14 ].

If metastasis occurs it is usually to the lung, which is not the most common metastatic site in human breast cancer - thus breast cancer metastasis is often studied through intravenous injection, enabling colonisation of specific organs; for example, intracarotid artery injection for study of brain metastasis or left ventricle injection for metastasis to bone.

Cell lines such as MDA-MB that are regarded as invasive in vitro remain relatively poorly metastatic in vivoalthough when introduced directly into the circulation the cell line has proved useful in models of experimental metastasis. Through rounds of in vivo selection, elegant experiments by Massague's group have developed highly metastatic derivatives of MDA-MB cells that home to particular metastatic sites, enabling generation of gene expression signatures linked with a specific metastatic site [ 56 ].

A review of this nature would be incomplete without reference to MDA-MB cells, which are spontaneously metastatic. A catalogue of the genomic and molecular properties of a breast cell line panel classified MDA-MB cells as basal B [ 22 ]. Hollestelle and colleagues also characterised MDA-MB as a basal cell line through gene expression microarray profiling [ 26 ], examples of breast cancer research papers ln.

The provenance of this cell line, however, is hotly debated. Originally isolated as part of the MD Anderson series hence the MDA prefix [ 58 ]these cells were thought to be derived from a breast carcinoma, but subsequent microarray and immunohistochemistry data have indicated that MDA-MB might originate from melanoma [ 59 — 61 ].

Despite clear controversies surrounding MDA-MB, many researchers continue to use this as a bona fide breast cancer cell line. We believe the persistent use of this cell line, including publications in high-impact journals - for example, where MDA-MB was used as a model of triple-negative breast cancer [ 62 ] - and even in specialist breast cancer journals [ 6364 ], is unacceptable as it is likely to generate potentially misleading data.

Nevertheless researchers are now more aware of the provenance of MDA-MB cells, with two recent papers using the cell line as a melanoma model [ 6566 ] and its inclusion in a list of cell lines of questionable origin examples of breast cancer research papers ln 67 ].

We urge researchers, members of grant review panels and journal reviewers and editors to be more aware of this. Indeed, many journals now have a policy of requesting some form of cell line authentication to accompany manuscript submission, which is something we support. Although there are now a reasonable number of breast cancer cell lines available to reflect the molecular sub-groups, relevant models are lacking for some of the rarer histopathological types.

There is a single report on the development of two cell lines from phyllodes tumours [ 68 ] examples of breast cancer research papers ln these do not seem have gained widespread use, examples of breast cancer research papers ln.

Cell lines derived from inflammatory breast cancer are limited to SUM and SUM [ 7 ], but the prevalence of the basal phenotype in this group [ 69 ] suggests basal cell lines may be used as surrogates. To our knowledge there is no known cell line derived from male breast cancer and, given that the incidence of male breast cancer is rising [ 70 ], examples of breast cancer research papers ln, this poses a challenge for modelling in a functional sense.

Tremendous advances in our understanding of the biology of breast cancer have been made over the past several decades using breast cancer cell lines. We must now move beyond the 'one marker, one cell line' studies of the past and use knowledge gained through genetic and transcriptomic profiling to use cell lines or cell line panels more effectively as experimental models to study specific subgroups of breast cancer, because this is likely to have the greatest impact on improving outcome for breast cancer patients.

Cancer Res. J Natl Cancer Inst. In Vitro.

 

Examples Of Breast Cancer Research Papers Ln | Essay Writing Help

 

examples of breast cancer research papers ln

 

Purpose. The purpose of this paper is to describe the content for the Asian American Network for Cancer Awareness Research and Training (AANCART) with respect to Asian American demographic characteristics and their cancer burden, highlights of accomplishments in various AANCART regions, aspirations for AANCART, and an interim assessment of AANCART’s activities to miccans.cf: Moon S Chen. Sep 28,  · Breast cancer is an increasing public health problem. Substantial advances have been made in the treatment of breast cancer, but the introduction of methods to predict women at elevated risk and prevent the disease has been less successful. Here, we summarize recent data on newer approaches to risk prediction, available approaches to prevention, how new approaches may be Cited by: examples of breast cancer research papers ln. habilitation thesis bibtex; help me with my book report bit of difference between the specic topic in this case would be significantly correlated student and dissertation research are frequently used as publicity, typically for a long tradition in biblical exegesis and scholarship, although as a.