cancer

Cancer

Cancer (in medical terms,  "malignancy ") is a type of disease in which a group of cells develop uncontrolled growth (divide beyond the normal limits), invasion (intrusion and destruction of adjacent tissues), and sometimes metastasis (spread to other parts of the body via lymph or blood). These three malignant properties of cancers are distinguished from benign tumors, which is autolimiten and not invade or metastatitzen. Most cancers form a tumor, but some, such as leukemia, do not. The branch of medicine that deals with the study, diagnosis, treatment and prevention of cancer is Oncology. Some types of cancer are colorectal cancer, colon cancer, liver cancer, breast cancer, skin cancer (melanoma), prostate cancer, lung cancer, leukemia.

The cancer can affect people of all ages, even the fetus, but in most types of cancer, the risk increases with age. [1] The cancer causes about 13% of all human deaths. [2] according to the American Cancer Society, 7.6 million people died of cancer worldwide during the year 2007. [3] The cancer can affect all animals.

Nearly all cancers are caused by abnormalities in the genetic material of the transformed cells. [4] these abnormalities may be due to the effects of carcinogens, such as tobacco smoke, radiation, chemicals or infectious agents. Other genetic abnormalities that contribute to cancer can be purchased at random due to errors in DNA replication, or are inherited, and thus present in all cells from birth. The heritability of cancers is usually affected by complex interactions between carcinogens and the genome of the host. Many new aspects of the genetics of cancer pathogenesis, such as DNA methylation, and microRNAs, are increasingly considered to be most important.

The genetic abnormalities that occur in cancer typically affect two general classes of genes. The promoters are usually activated oncogenes to cancer in the cancer cells, giving them new properties such as hyperactive growth and Division, protection against programmed cell death, a loss of respect for the limits between normal tissue and the ability to settle in various tissue media. Tumour suppressors genes are activated in cancer cells, causing the loss of normal functions in those cells, such as a proper DNA replication, cell cycle control, orientation and adhesion within tissues, and the interaction with protective cells of the immune system.

The diagnosis usually require a histological examination of a tissue biopsy specimen by a pathologist, although the first signs of a malignancy can be symptoms or abnormalities in the x-rays. Most cancers can be treated, and some can be cured, according to the type, location and the stadium. Once diagnosed, the cancer is usually treated with a combination of surgery, chemotherapy and radiotherapy. As it carries out research, the treatments were becoming more specific to the different varieties of cancer. There have been significant advances in the development of targeted therapy drugs that Act specifically on detectable molecular abnormalities in certain tumors, and that minimize damage to normal cells. The prognosis of cancer patients mainly depends on the type of cancer, as well as the stadium, or progress, of the disease. In addition, the histological graduation and the presence of specific molecular markers can also been useful to establish a prognosis, as well as to determine the individual treatments.

Content
1 Classification
2 Features
2.1 Morphology
2.2 tumour growth
2.3 local Invasion
2.4 Metastasis
3 molecular biology of cancer
3.1 Carcinogenesis
3.2 Genetics
clonal Nature 3.3
4 Nomenclature
5 Diagnosis
5.1 Biopsy
5.2 Estadificació
6 Treatment
7 Forecast
8 Prevention
8.1 primary prevention
8.2 Secondary Prevention
9 cancer epidemiology
9.1 Mortality
9.2 Risk Factors
9.3 Incidence
10 related Articles
11 References
12 Bibliography
13 external Links
Classification

Cancers are classified according to the type of cell that more resembles the tumor and, therefore, the tissue that is supposed to have originated the tumor. This are the histology and location, respectively. Some examples of general categories are:

Carcinoma: malignant tumors derived from epithelial cells. This group are the most common cancers, including the common forms of breast cancer, prostate, lung and colon.

Sarcoma: malignant tumors derived from connective tissue, mesenchymal cells.

Lymphoma and leukemia: cancer-derived hematopoietic cells (the blood).

Germline cells tumor: tumors derived from totipotents cells. In adults, often occur in the testes and ovaries; in fetuses, babies and children are given above all to the median line of the body, especially at the end of the coccyx; in horses (especially at the base of the skull).

Blàstic tumor or blastoma: a tumor (usually malignant) which resembles the immature tissue or embryo. Many of these tumors are most common in children.

Malignancies (cancers) are usually called using the suffixes-sarcoma, carcinoma-or-blastoma, and using the name Latin or Greek of the organ of origin as a root. For example, a liver cancer receives the name of hepatocarcinoma; a cancer of the cells of the adipose tissue is a liposarcoma. For the most common cancers, used the name in Catalan. For example, the most common type of breast cancer is called ductal carcinoma of the breast or mammary ductal carcinoma. Here, the adjective  "ductal " refers to the aspect that presents the cancer under the microscope, which is similar to the normal breast ductes.

Benign tumors (those that are not cancers) are named using the suffix-oma and the name of the body as a root. For example, a benign tumor of the smooth muscle of the uterus is called leiomioma (the common name of this frequent tumor is  "fibroide "). Unfortunately, some cancers also use the suffix-oma, such as melanomas and seminomes.

Characteristics

Morphology

Tumor cells have an altered morphology that depends on the differentiation and the anaplàsia. The differentiation of a tumor is the degree to which the cells would seem to be normal cells parenchymatous lesions from which they come, both morphologically and functional. Benign tumors usually are well differentiated and cancers vary from undifferentiated to well-differentiated. The anaplàsia is the absence of differentiation that leads to a lack of expertise or of cellular function and generally the more anaplàsic is a higher cancer is its speed of growth.

Tumor growth

The tumor growing or the proliferation of tumor cells has the following characteristics:

Accelerated by an increase in cell division that causes the tumor cells are in continuous cell cycle with excessive cell proliferation.

Decrease, due to the fact that it is not let influence by growth factors or other external stimuli.

Stand-alone: cell division is independent and is not coordinated with the rest of the surrounding cells.

Escape to the immune system that recognizes the tumor cells as its own.

Inhibition of the processes of death: tumor cells never enter apoptosis or programmed cell death.

Local invasion

The invasion is the ability to have the tumor cells to infiltrate and penetrate the normal tissues and in blood vessels and cause metastasis. The invasion is not only due to the pressure of the tumor growth, but to phenotypical characteristics that they acquire the cancer cells. The pillars on which is based the invasion are:

Angiogenesis/neovascularization: is the ability to form new blood vessels by the secretion of growth factors such as vascular endothelial growth Factor (VEGF). The new glasses are essential for the nutrition of tumour cells and to be able to metastatitzar. [5] [6]

Grip: it is the anchoring of the tumor cell by means of the acquisition of specific receptors in the basal membrane and extracellular matrix. These receptors are for Integrin, MAC and caderines.

The destruction of the basal membrane is Proteòlisi and cellular matrix by the secretion of enzymes, such as col·lagenases, that destroy collagen and so be able to carve out a niche between these structures.

Mobility: is the migration or locomotion of the malignant cells through the cell matrix to achieve a blood vessel or lymphatic, intravasar, be transported by the blood stream to distant capillaries, extravasar and migrate a certain distance to start the formation of a new colony (metastasis).

Metastasis

Metastasis is the spread to distant organs of primary tumor malignant. [7] [8] [9] generally Occurs via blood or lymphatic.

Molecular biology of cancer

Carcinogenesis

Carcinogenesis is the formation of cancer through the carcinogenic or genetic diseases. [10]

Genetics

Cancer is a genetic disease caused by the mutation of certain genes in a particular cell and that acquires the characteristics of the cancer. These genes are of three types:

Oncogenes: Are the mutated genes that come from other so-called protooncogens responsible for the regulation of cell growth. [11]

Tumour suppressors genes: they are responsible to stop cell division and cause apoptosis. When these genes mutate the cell divides uncontrollably. [12]

DNA repair genes: When the repair system is faulty as a result of a mutation acquired or inherited, the rate of accumulation of mutations in the genome rises as cell divisions occur. According to the degree to which these mutations affect oncogenes and tumour suppressor genes in cancer, will increase the probability of suffering from malignant tumours.

Clonal nature

The cancers originate from a cell only after multiple mutations (five to ten) in the genotype to be transforme into a malignant Phenotype in the course of several years, giving rise to a clone of cells that is the tumor.

Nomenclature

All tumors, benign and malignant have two basic components in its structure:

Neoplàstiques cells proliferants that constitute the parenchyma.

The stroma of connective tissue and blood vessels, set up by the BRA.

The oncological nomenclature is based on the component parenquimatós. According to the behaviour of tumors:

Benign tumors: its name ends with the suffix-oma, simply and according to the origin of the fabric of that benign tumors can be annotated: fibroid (fibrous connective tissue), mixoma (connective tissue laxe), lipoma (adipose tissue), condroma (tissue cartilage), osteoma (bone tissue) or angioma, hemangioma (vascular tissue), limfangioma (lymphatic tissue), meningioma (meninges), tumor glòmic (nerve tissue of sostén), uterine fibroid (smooth muscle tissue), rabdomioma (striated muscle tissue), papillae · Loma (epithelial tissue forming buds), BPH (glandular tissue), teratoma (totipotencials cells), nevi (melanocytes).

Malignant tumors or cancer:

Cancers arising from tissues mesenquimàtics or mesoderma called sarcomas (of sar flu,  "fleshy "), for example mixosarcoma, condrosarcoma, fibrosarcoma, liposarcoma, osteosarcoma, angiosarcoma, lifangiosarcoma, sinoviosarcoma, Mesothelioma (pleural tissue), liomiosarcoma, Rhabdomyosarcoma.

Malignant tumours of epithelial origin, derived from any of the three germ layers of the embryo, are referred to as carcinomas, squamous basocelular carcinoma epidermoide carcinoma or, for example, adenocarcinoma, cistoadenocarcinoma, coriocarcinoma.

The nervous tissue from tumors are gliomas.

Haematological cancers include lymphomas [13] and the leukemia. [14]

The malignant tumors that do not comply with the above rules and end in-oma are: melanoma, the hepatoma all exhibited, the seminoma.

Diagnosis

Biopsy

The diagnosis of cancer is based on indispensablement in the rush of a biopsy of the tumor in order to make a histological study with the degree of differentiation and invasion, and by a molecular study to determine their biological and genetic markers. Any cancer diagnosis is valid if it is not based on the study of a biopsy, and therefore the medical staff will make all the efforts to get a sample of tissue for confirming the diagnosis of cancer before the persistence of clinical suspicion.

Estadificació

Main article: cancer Estadificació

Determines the extent of the cancer disease based on the concept of what the cancer spreads spatially in the body in three levels that are local, regional and distance. There are two types of estadificció are:

The estadificació clinical cancer based on the physical examination, x-rays, CT, the MRI, the MRI and other imaging techniques.

The estadificació anatomopatològica or surgical cancer that involves the analysis of histological all tissues excised during surgery, which may take place during the removal of the original tumor or as a part of the staging.

The TNM staging system (tumor, node (node) and metastasis) is the most employee. Assesses the local disease (tumor size), regional (number of affected nodes) and propagation distance (presence of metastasis). The TNM was codified by the International Union Against Cancer [15] and the American Joint Committee on Cancer. [16]

Treatment

Is based on three basic pillars: surgery, chemotherapy and radiotherapy. There is a fourth via so-called biological therapy which includes the hormonotherapy, immunotherapy, and new therapeutic targets do not citotòxiques. The treatment of cancer is multi-disciplinary cooperation between the different professionals involved (surgeons, oncologists and medical oncologists radiation therapists), it is of utmost importance for the planning of cancer treatment; without the informed consent of the patient.

In the treatment plan you must define whether the treatment will be with curative intent or intention palliative.

The response to treatment can be:

Complete: If there has been the disappearance of all signs and symptoms of the disease.

In part: If there is a reduction of 50% on the sum of the products of the perpendicular diameters of all measurable lesions.

Objective: complete or partial response is.

Progression: If you see any new injury or there is an increase of 25% on the sum of the products of the perpendicular diameters of all measurable lesions.

Stable: If there is growth or reduction of the tumor that does not meet any of the criteria above.

When it is not possible the extent of the injury, tumor markers are useful to evaluate the response to treatment.

Weather forecast

From the Decade of 1990 and the therapeutic techniques available, the cancer is curable in about 50% of patients diagnosed. The prognosis of cancer depends mostly on:

The anatomical location of the primary tumor.

Histological type with the degree of cell differentiation, the biological and cytogenetic characteristics.

The stadium of cancer or spread of the disease.

The age of the patient.

The functional or physiological reserve status of the patient.

Prevention

Although the cause of the cancer is unknown in many cases and can be attributed in others, there are some risk factors that increase the likelihood of contracting cancer and which should be avoided, such as tobacco. It is estimated that up to 50% of the cancers might be avoidable.

Primary prevention

Education and healthy habits:

Quit: saves and prolongs life, more than any public health activity.

Healthy diet.

Avoid exposure to the Sun.

Quimioprevenció: Is the use of certain chemicals, natural or synthetic, to reverse, suppress or prevent carcinogenesis before development of a malignancy.

Quimioevitació: is the avoidance of certain carcinogenic chemicals or those who do not have the security that do not cause cancer.

Vaccine: vaccinations for certain viruses, can prevent certain types of cancer. For example the universal vaccination against hepatitis B, can reduce the incidence of hepatoma all exhibited.

Secondary prevention

Is the early detection of cancer in asymptomatic individuals, with the aim of decreasing morbidity and deadliness.

Cancer epidemiology

Main article: cancer epidemiology

Mortality

Cancer is the second leading cause of death after heart disease. However, deaths from cardiovascular disease are reducing, while deaths from cancer are increasing. It is estimated that over the course of the 21st century, cancer is the leading cause of death in developed countries. Despite this, there has been an increase in the survival of patients with cancer.

Risk factors
The main risk factor is age, since two-thirds of all cancers occur in people over the age of 65 years. The second risk factor is smoking and you follow the diet, physical exercise, sun exposure, and other styles of life.

Incidence
The incident in Spain is 150,000 cases/year (90,000 cases in men and 60,000 cases in women), which for the most part are cancers of the skin that are relatively easy to cure. They are actually one of the main causes of death. The locations of these disorders, not tegumentaris, are according to the frequency of cases:

Men: prostate, colorectal and lung [19]
Still according to mortality: Lung, prostate and colorectal [20]
In women: breast, lung and colorectal [21]
Breast, lung and colorectal mortality as being: [20]
Related articles
Neoplasia: literally means  "new growth ",  "new " or's "new " but is used only in the sense of  "cell proliferation ". The Neoplasms can be benign or malignant. If you used the term "neoplasm"   or neo isolation, means  "malignant cell proliferation ".
Tumour: Originally this term is applied to the swelling, inflammation or increase in size of an organ or tissue with the inflammation. With the course of time she forgot the sense not tumor neoplàsic and at present the term tumor is the equivalent or synonym of neoplasia. There are benign tumors and malignant tumors.
Oncology: the Greek's "oncos ", tumor, is the part of medicine that studies tumors or hematological, especially malignant (cancer).