Cancer can be defined as a disease in which a group of abnormal cells grow uncontrollably by disregarding the normal rules of cell division. Normal cells are constantly subject to signals that dictate whether the cell should divide, differentiate into another cell or die. Cancer cells develop a degree of autonomy from these signals, resulting in uncontrolled growth and proliferation. If this proliferation is allowed to continue and spread, it can be fatal. In fact, almost 90% of cancer-related deaths are due to tumour spreading – a process called metastasis....
Over the last three decades, knowledge on the molecular biology of human cancers has vastly expanded. A host of genes and proteins involved in cancer development and progression have been defined and many mechanisms at the molecular, cellular and even tissue level have been, at least partly, elucidated. Insights have also been gained into the molecular mechanisms underlying carcinogenesis by chemical, physical, and biological agents and into inherited susceptibility to cancer. Accordingly, Part I of the book presents many of the molecules and mechanisms generally important in human cancers.
Harrison's Internal Medicine Chapter 80. Cancer Cell Biology and Angiogenesis
Cancer Cell Biology and Angiogenesis: Introduction Two characteristic features define a cancer: unregulated cell growth and tissue invasion/metastasis. Unregulated cell growth without invasion is a feature of benign neoplasms, or new growths. Cancer is a synonym for malignant neoplasm. Cancers of epithelial tissues are called carcinomas; cancers of nonepithelial (mesenchymal) tissues are called sarcomas. Cancers arising from hematopoietic or lymphoid cells are called leukemias or lymphomas.
Head and Neck Cancer: Treatment Patients with head and neck cancer can be categorized into three clinical groups: those with localized disease, those with locally or regionally advanced disease, and those with recurrent and/or metastatic disease. Comorbidities associated with tobacco and alcohol abuse can affect treatment outcome and define long-term risks for patients who are cured of their disease.
Nearly one-third of patients have localized disease; that is, T1 or T2 (stage I or stage II) lesions without detectable lymph node involvement or distant metastases.
There have been a significant number of advances
in the field of cancer research since the
first edition of Cancer Biology, which was published
in 1981. These include advances in defining
the genetic and phenotypic changes in cancer
cells, the genetic susceptibility to cancer, molecular
imaging to detect smaller and smaller tumors,
the regulation of gene expression, and the
‘‘-omics’’ techniquesofgenomics, proteomics,and
metabolomics, among others.
Defining the Extent of Disease and the Prognosis The first priority in patient management after the diagnosis of cancer is established and shared with the patient is to determine the extent of disease. The curability of a tumor usually is inversely proportional to the tumor burden. Ideally, the tumor will be diagnosed before symptoms develop or as a consequence of screening efforts (Chap. 78). A very high proportion of such patients can be cured.
Staging As noted in Chap. 77, an important component of patient management is defining the extent of disease. Radiographic and other imaging tests can be helpful in defining the clinical stage; however, pathologic staging requires defining the extent of involvement by documenting the histologic presence of tumor in tissue biopsies obtained through a surgical procedure.
Karnofsky was among the first to champion the evaluation of a chemotherapeutic agent's benefit by carefully quantitating its effect on tumor size and using these measurements to objectively decide the basis for further treatment of a particular patient or further clinical evaluation of a drug's potential.
Following demonstration of activity in animal models, conventional chemotherapeutic agents are further evaluated to define an optimal schedule of administration and arrive at a drug formulation designed for a given route and schedule. Safety testing in two species on an analogous schedule of administration defines the starting dose for a phase I trial in humans. This is established as a fraction, usually one-sixth to one-tenth, of the dose just causing easily reversible toxicity in the more sensitive animal species.
Hanna Willander1,2, EriThe BRICHOS domain was initially defined from sequence alignments of
the Bri protein associated with familial dementia, chondromodulin associ-ated with chondrosarcoma and surfactant protein C precursor (proSP-C)
associated with respiratory distress syndrome and interstitial lung disease
(ILD). Today BRICHOS has been found in 12 protein families.
For example, a decision must be
taken on whether to include cases for which the most valid basis of diag-
nosis is solely clinical. A decision should also be taken regarding cases
registered on the basis of a death certificate only (DCO), for whom no
information is available on the date of diagnosis of the cancer. The most
usual practice is to omit these cases from the analysis, but if they repre-
sent a large proportion of registrations, it may be better to present two
survival analyses, one including DCO cases and another excluding them.
The second requirement is a clear and well defined starting point. For popu-
lation-based cancer registries, the starting date (from which the survival is
calculated) is the incidence date (see Section 17.3.1).
The third requirement is a clear and well defined outcome. Death is gener-
ally the outcome of interest, but some registries collect enough data to allow
them to conduct analyses using recurrence of tumour, or first recurrence of
a particular complication, as the outcome of interest.
In addition to explicitly named Properties, “code” and “id” attributes are special cases. Every entity in the Thésaurus
– Concepts, Kinds, Properties, and Roles – has an associated “code” and “id.” These are used as unique identifiers in
the Apelon development software, and, as such, are not defined explicitly as Roles or Properties. This required a
hard-coded definition of both entities. They were defined as owl:AnnotationProperties, just like other Properties in
the Thésaurus, and this allowed them to be attached to all of the definitions in the ontology.
Meat has long been a central component of the human diet, both as a food in its own right and as an essential ingredient in many other food products. Its importance has also attracted controversy. Meat consumption has, for example, been associated with chronic diseases such as cancer and heart disease. These and other concerns, such as those over safety, have led to declining consumption
of some types of red meat in regions such as the EU. As a result, the questions of what defines meat quality in the minds of consumers, and the ways these quality attributes can be maintained...
The medical consequences of
operating outside of the normal boundaries of a well tuned musculo-tendinous system are
also poorly understood, although clearly recognized in the persistent atrophy experienced
in microgravity despite rigorous exercise programs.
Muscle force generation is length and velocity sensitive. The process is repetitive in the
sense that muscles will always generate force based on their length-tension and forcevelocity
properties, causing tendon deformation.
Mexican market researchers have defined three “Socio-Economic Levels” (SEL;
niveles socioeconómicos) of Mexico’s urban population which is of particular
interest to marketers.
1 The high Socio-Economic Level (SEL) makes up around 8%
of the urban population of Mexico (see Table 4). This is beyond any doubt the
most interesting customer segment for Swiss exporters of high quality consumer
products. Parts of the Medium SEL (which totals 29% of the urban population)
might also be in a position to afford Swiss products.
Two characteristic features define a cancer: unregulated cell growth and tissue invasion/metastasis. Unregulated cell growth without invasion is a feature of benign neoplasms, or new growths. Cancer is a synonym for malignant neoplasm. Cancers of epithelial tissues are called carcinomas; cancers of nonepithelial (mesenchymal) tissues are called sarcomas. Cancers arising from hematopoietic or lymphoid cells are called leukemias or lymphomas. Cancer is a genetic disease.
We anticipate that this update will continue to raise awareness among clinicians and policymakers alike that low health literacy has a substantial impact on the use of health care services and health outcomes; it also hints at the role of health literacy in disparities in utilization or outcomes among groups defined by various sociodemographic characteristics. However, little remains known about the direct effect of lower health literacy on the costs of health care. Addressing the burden of low health literacy that we have identified warrants the attention of many stakeholders.
Many people who develop materials try to create something for “everyone.” After all, everyone
needs good information and would probably benefit from knowing what you have to say. In
reality, no one thing is right for everyone. Instead, certain things tend to work best for certain
groups of people. The more narrowly you can define these groups, the closer you will come to
meeting their needs. That is why materials should speak to a particular audience: people who
share similar characteristics and have similar information needs.