Malignant transformation
Encyclopedia
Malignant transformation is the process by which cells acquire the properties of cancer
. This may occur as a primary process in normal tissue, or secondarily as malignant degeneration of a previously existing benign tumor.
There are many causes of primary malignant transformation, or tumorigenesis. The underlying commonality is genetic mutation either by inheritance or more commonly by acquiring mutations in one's DNA
over time. Although malignant transformation may occur because of changes within the cell, it can be induced by inorganic toxic substances such as cadmium
or arsenite
and organics such as tobacco-specific nitrosamines. It is also thought that some malignant transformations are due to viruses such as the Epstein-Barr virus, although this is currently restricted to just a few cancer types. A more common cancer associated with viral infection is cervical cancer
, which has been linked to the human papilloma virus.
Malignant transformation of cells in a benign tumor may be detected by pathologic
examination of tissues. Often the clinical signs and symptoms are suggestive of a malignant tumor. The physician, during the medical history
examination, can find that there have been changes in size or patient sensation and, upon direct examination, that there has been a change in the lesion
itself.
Risk assessment
s can be done and are known for certain types of benign tumor which are known to undergo malignant transformation. One of the better known examples of this phenomenon is the progression of a nevus
to melanoma
.
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
. This may occur as a primary process in normal tissue, or secondarily as malignant degeneration of a previously existing benign tumor.
There are many causes of primary malignant transformation, or tumorigenesis. The underlying commonality is genetic mutation either by inheritance or more commonly by acquiring mutations in one's DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...
over time. Although malignant transformation may occur because of changes within the cell, it can be induced by inorganic toxic substances such as cadmium
Cadmium
Cadmium is a chemical element with the symbol Cd and atomic number 48. This soft, bluish-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Similar to zinc, it prefers oxidation state +2 in most of its compounds and similar to mercury it shows a low...
or arsenite
Arsenite
In chemistry an arsenite is a chemical compound containing an arsenic oxoanion where arsenic has oxidation state +3.The different forms of the anion are the next ones:* ortho-arsenite: AsO33-* meta-arsenite: AsO2-...
and organics such as tobacco-specific nitrosamines. It is also thought that some malignant transformations are due to viruses such as the Epstein-Barr virus, although this is currently restricted to just a few cancer types. A more common cancer associated with viral infection is cervical cancer
Cervical cancer
Cervical cancer is malignant neoplasm of the cervix uteri or cervical area. One of the most common symptoms is abnormal vaginal bleeding, but in some cases there may be no obvious symptoms until the cancer is in its advanced stages...
, which has been linked to the human papilloma virus.
Malignant transformation of cells in a benign tumor may be detected by pathologic
Pathology
Pathology is the precise study and diagnosis of disease. The word pathology is from Ancient Greek , pathos, "feeling, suffering"; and , -logia, "the study of". Pathologization, to pathologize, refers to the process of defining a condition or behavior as pathological, e.g. pathological gambling....
examination of tissues. Often the clinical signs and symptoms are suggestive of a malignant tumor. The physician, during the medical history
Medical history
The medical history or anamnesis of a patient is information gained by a physician by asking specific questions, either of the patient or of other people who know the person and can give suitable information , with the aim of obtaining information useful in formulating a diagnosis and providing...
examination, can find that there have been changes in size or patient sensation and, upon direct examination, that there has been a change in the lesion
Lesion
A lesion is any abnormality in the tissue of an organism , usually caused by disease or trauma. Lesion is derived from the Latin word laesio which means injury.- Types :...
itself.
Risk assessment
Risk assessment
Risk assessment is a step in a risk management procedure. Risk assessment is the determination of quantitative or qualitative value of risk related to a concrete situation and a recognized threat...
s can be done and are known for certain types of benign tumor which are known to undergo malignant transformation. One of the better known examples of this phenomenon is the progression of a nevus
Nevus
Nevus is the medical term for sharply-circumscribed and chronic lesions of the skin. These lesions are commonly named birthmarks and moles. Nevi are benign by definition...
to melanoma
Melanoma
Melanoma is a malignant tumor of melanocytes. Melanocytes are cells that produce the dark pigment, melanin, which is responsible for the color of skin. They predominantly occur in skin, but are also found in other parts of the body, including the bowel and the eye...
.
See also
- Teratoma with malignant transformationTeratomaA teratoma is an encapsulated tumor with tissue or organ components resembling normal derivatives of all three germ layers. There are rare occasions when not all three germ layers are identifiable...
- Richter's transformationRichter's transformationRichter's transformation, or Richter's syndrome is a complication of B cell chronic lymphocytic leukemia or hairy cell leukemia in which the leukemia changes into a fast-growing diffuse large B cell lymphoma. There is also a less common variant in which the CLL changes into a Hodgkin's lymphoma...
in blood cancers