山西医科大学研究生毕业专业英语题

一、英译汉（80分，要求全部段落进行概要性翻译）

1. 第一部分（40分）

The tumor-associated microenvironment, which consists of extracellular matrix (ECM), cancer-associated fibroblasts (CAFs), inflammatory immune cells, and tumor-associated vasculature, plays a critical role during tumorigenesis. CAFs, which are abundant in tumor-associated stroma, secrete several factors, including HGF and SDF1, to promote epithelial cell neoplastic transformation and cancer cell proliferation. In addition, CAFs interact with other stromal components to stimulate tumor-enhancing inflammation and angiogenesis. Moreover, ECM remodeling by CAFs is essential for tumor cell invasion and metastasis. Although CAFs are important constituents of the tumor stroma, the paracrine signals that mediate direct crosstalk between CAFs and tumor cells in metastasis are poorly understood.

Exosomes are membrane vesicles that originate in large multivesicular bodies (MVBs) and are released in the extracellular milieu upon fusion of MVBs with the plasma membrane. Exosomes have the same topology as a cell and contain a broad array of biologically active material. Several cellular components of the tumor microenvironment and cancer cells secrete exosomes that function in an autocrine or paracrine manner to promote tumor-induced immune suppression, angiogenesis, and premetastatic niche formation. Currently, it is unknown whether CAFs secrete exosomes and whether these microvesicles support cancer cell metastasis.

2. 第二部分（20分）

Because the spectrum of cancer care includes screening as well as treatment, a comprehensive understanding of breast cancer cost must incorporate the cost of screening and associated workup. While the body of evidence concerning Medicare expenditures for cancer treatment has grown, relatively little is known about cost associated with screening Medicare beneficiaries for breast cancer. This is especially important among older women because recent guidelines have concluded that there is insufficient evidence to assess the benefits and harms of screening mammography in women 75 years or older.

It is particularly timely to consider the cost implications of breast cancer screening because newer breast cancer screening technologies, such as digital mammography and computer-aided

detection (CAD), have expanded the options available to clinicians and are diffusing into clinical practice. The adoption of these new technologies can increase costs directly through reimbursement for the tests and also lead to higher rates of supplementary imaging, biopsy, or cancer detection. It is critical to assess the relation between screening expenditures and population outcomes since newer modalities can increase cancer detection rates but may not improve patient outcomes, particularly among older women.

Ideally, higher breast cancer screening expenditures at the population level should correspond to earlier stage at diagnosis, lower treatment cost, or both. This can be evaluated by comparing differences in screening cost and cancer outcomes across geographic regions, hypothesizing that women living in regions that “invest” more in screening services may be less likely to be diagnosed at a later stage. However, in actual practice, it is unclear whether higher screening costs are associated with earlier stage at diagnosis or lower cancer treatment costs at the population level. To address these knowledge gaps, we estimated national breast cancer screening and treatment costs in the Medicare fee-for-service program. Our second objective was to assess regional variation in breast cancer screening cost, while our third objective was to determine the association between regional screening cost and breast cancer incidence and treatment costs. These data will inform clinicians and policy makers in a context of debate about Medicare reimbursement for various cancer screening modalities and concerns about growth in cancer expenditures.

3. 第三部分（20分）

The Nobel Assembly at Karolinska Institutet has today decided to award: The Nobel Prize in Physiology or Medicine 2012 jointly to-John B. Gurdon and Shinya Yamanaka(山中伸弥) for the discovery that mature cells can be reprogrammed to become pluripotent.

Summary

The Nobel Prize recognizes two scientists who discovered that mature, specialised cells can be reprogrammed to become immature cells capable of developing into all tissues of the body. Their findings have revolutionised our understanding of how cells and organisms develop. John B. Gurdon discovered in 1962 that the specialisation of cells is reversible. In a classic experiment, he replaced the immature cell nucleus in an egg cell of a frog with the nucleus from a mature