Colon cancer Colon cancer Colon cancer can occur in any part of the colon. An examination of your entire colon using a long, flexible tube equipped with a camera colonoscopy is one way to detect colon cancer and polyps. Colon cancer is cancer of the large intestine colonwhich is the final part of your digestive tract.
Sinauer Associates ; Search term The Development and Causes of Cancer The fundamental abnormality resulting in The underlying pathophysiology of cancer development of cancer is the continual unregulated proliferation of cancer cells. Rather than responding appropriately to the signals that control normal cell behavior, cancer cells grow and divide in an uncontrolled manner, invading normal tissues and organs and eventually spreading throughout the body.
The generalized loss of growth control exhibited by cancer cells is the net result of accumulated abnormalities in multiple cell regulatory systems and is reflected in several aspects of cell behavior that distinguish cancer cells from their normal counterparts.
Types of Cancer Cancer can result from abnormal proliferation of any of the different kinds of cells in the body, so there are more than a hundred distinct types of cancerwhich can vary substantially in their behavior and response to treatment. The most important issue in cancer pathology is the distinction between benign and malignant tumors Figure A tumor is any abnormal proliferation of cells, which may be either benign or malignant.
A benign tumorsuch as a common skin wart, remains confined to its original location, neither invading surrounding normal tissue nor spreading to distant body sites.
A malignant tumorhowever, is capable of both invading surrounding normal tissue and spreading throughout the body via the circulatory or lymphatic systems metastasis.
Only malignant tumors are properly referred to as cancers, and it is their ability to invade and metastasize that makes cancer so dangerous. Whereas benign tumors can usually be removed surgically, the spread of malignant tumors to distant body sites frequently makes them resistant to such localized treatment.
Micrographs of normal uterus A and a section of a uterine sarcoma B. Note that the cancer cells darkly stained have invaded the surrounding normal tissue. Both benign and malignant tumors are classified according to the type of cell from which they arise.
Most cancers fall into one of three main groups: Sarcomaswhich are rare in humans, are solid tumors of connective tissues, such as muscle, bone, cartilage, and fibrous tissue. Tumors are further classified according to tissue of origin e.
For example, fibrosarcomas arise from fibroblasts, and erythroid leukemias from precursors of erythrocytes red blood cells. Although there are many kinds of canceronly a few occur frequently Table More than a million cases of cancer are diagnosed annually in the United States, and more thanAmericans die of cancer each year.
The Development of Cancer One of the fundamental features of cancer is tumor clonality, the development of tumors from single cells that begin to proliferate abnormally. The single-cell origin of many tumors has been demonstrated by analysis of X chromosome inactivation Figure As discussed in Chapter 8, one member of the X chromosome pair is inactivated by being converted to heterochromatin in female cells.
X inactivation occurs randomly during embryonic development, so one X chromosome is inactivated in some cells, while the other X chromosome is inactivated in other cells.
Thus, if a female is heterozygous for an X chromosome genedifferent alleles will be expressed in different cells. Normal tissues are composed of mixtures of cells with different inactive X chromosomesso expression of both alleles is detected in normal tissues of heterozygous females.
In contrast, tumor tissues generally express only one allele of a heterozygous X chromosome gene. The implication is that all of the cells constituting such a tumor were derived from a single cell of origin, in which the pattern of X inactivation was fixed before the tumor began to develop.
Normal tissue is a mosaic of cells in which different X chromosomes X1 and X2 have been inactivated. Tumors develop from a single initially altered cell, so each tumor cell displays the same pattern of X inactivation X1 inactive, X more The clonal origin of tumors does not, however, imply that the original progenitor cell that gives rise to a tumor has initially acquired all of the characteristics of a cancer cell.
On the contrary, the development of cancer is a multistep process in which cells gradually become malignant through a progressive series of alterations. One indication of the multistep development of cancer is that most cancers develop late in life. The incidence of colon cancer, for example, increases more than tenfold between the ages of 30 and 50, and another tenfold between 50 and 70 Figure Such a dramatic increase of cancer incidence with age suggests that most cancers develop as a consequence of multiple abnormalities, which accumulate over periods of many years.Discuss the underlying pathophysiology of cancer and how this applies to Mrs Lane 1 Development of colorectal cancer Colorectal cancer is a malignant neoplasm in the large intestine and generally limited locally for a long term before invasion and metastasis (The Cancer Council Australia & .
What Causes Pancreatic Cancer? Scientists don’t know exactly what causes most pancreatic cancers, but they have found several risk factors that can make a person more likely to get this disease. Some of these risk factors affect the DNA of cells in the pancreas, which can result in abnormal cell growth and may cause tumors to form.
Looking for online definition of pathophysiology in the Medical Dictionary? pathophysiology explanation free. the study of the biological and physical manifestations of disease as they correlate with the underlying abnormalities and physiological disturbances.
What is the best pathophysiology of colorectal cancer. The pathophysiology. Cancer is a complex group of diseases with many possible causes. In this section you can learn more about the known and possible causes of cancer, as well as general information about carcinogens and how genetics play a role in cancer.
The cancer cells invade the underlying connective. Causes of Cancer. Substances that cause cancer, called carcinogens, have been identified both by studies in experimental animals and by epidemiological analysis of cancer frequencies in human populations (e.g., the high incidence of lung cancer among cigarette smokers).
Since the . Colorectal cancer, disease characterized by uncontrolled growth of cells within the large intestine (colon) or rectum (terminal portion of the large intestine).
Colon cancer (or bowel cancer) and rectal cancer are sometimes referred to separately. Colorectal cancer develops slowly but can spread to surrounding and distant tissues of the body.