Location of the thyroid gland
The thyroid gland is located at the frontof the neck. For most people, it can be seen or probe. The thyroid gland has two lobes connected by a narrow isthmus. This gland absorbs iodine from food and blood and produces a hormone that performs different functions. The thyroid gland contains mainly two kinds of cells:
Follicular cells that produce andkeep the thyroid hormone. In addition, they produce a protein called special thyroglobulin, and cells that produce another hormone - calcitonin.
Among these cells there are various types of cancer, characterized by the flow, treatment and outcome.
As there are various thyroid tumorwith the majority of them (about 95%) - benign. Due to the fact that the thyroid gland is located close to the skin, tumor, which arose in it, it has the form of the neck assembly. Nodes in the gland can occur at any age, most often detected in adults who find themselves at the tumor.
Malignant tumor of the thyroid
Only 10.5% of thyroid tumors are malignant. There are several types of thyroid cancer:
Papillary carcinoma is 80-85% of the totalthyroid malignancies. The tumor grows very slowly and there is usually a fraction of one gland, but 10-20% of patients with bilateral loss happens. Although the tumor grows slowly, but often affects the cervical lymph nodes. Fortunately, most people with papillary thyroid cancer is recovering.
Follicular carcinoma is the second most common malignantthyroid tumor and 5-10% of all prostate tumors. It is often detected in countries where there is a lack of iodine in the diet. Usually this type of cancer is within the thyroid gland, but it may metastasize to the lung and bone. Unlike papillary carcinoma, follicular carcinoma rarely involve a process in lymph nodes. The prognosis for patients with follicular carcinoma is the same or slightly worse than that of patients with papillary carcinoma.
Anaplastic carcinoma - A rare type of malignant tumor of the thyroid. Swelling quickly affects structures of the neck and spreads throughout the body, leading often to death.
Medullary carcinoma of thyroid - The only tumor that arises from C cellsand 5% of total prostate malignancies. It can affect the lymph nodes, lungs and liver before identifying the primary tumor. This swelling produces calcitonin carcinoembryonic antigen and a hormone that can be detected in the patient's blood.
Lymphoma of the thyroid gland develops from lymphocytes - immune system cells, but is very rare.
The causes of thyroid cancer
The incidence of thyroid cancer in the world is low - about
1-2% of all cancer. In the absence of radiation
impact frequency of thyroid cancer increases with
age. If you have children, it is extremely rare, then over 60 persons
s half of the cases, you can identify the nodal forms of cancer. Chernobyl
disaster showed that the exposure of children, including prenatal
exposure, dramatically increasing incidence of thyroid cancer.
The reason lies in that the radioactive iodine accumulates in
the thyroid gland, which in utero and in childhood
age is many times more sensitive to the effects of radiation. adults
We observed the same trend but much less pronounced since for
tumor development requires much higher doses and time for
Manifestations of pathology.
There has been great progress in understanding howchanges in DNA can transform normal human thyroid cells in malignant. DNA is the molecule that carries information about the activity of all body cells. We usually resemble our parents, as they are the source of our DNA. However, DNA influences not only in our appearance. It also determines the risk of developing certain diseases, including cancer.
Some genes (pieces of DNA) control the growth andcell division. Genes that promote cell division, called oncogenes. Other genes slow down cell division or cause their death, and they are called tumor-suppressive genes. Neoplasms may arise as a result of mutations (changes) genes and their effects on oncogenes and tumor-suppressor genes.
People can inherit damaged DNA fromparent. In many cases, the human DNA is damaged by the impact of environmental factors such as smoking or radiation. Sometimes DNA mutations occur for unknown reasons.
Mutations in DNA that cause some formspapillary thyroid cancer, involve certain parts oncogene RET. These mutations are acquired during life and rarely inherited. They are present only in tumor cells and not transmitted to the patient's children. Acquired changes in other oncogenes and tumor-suppressor genes also play a role in the occurrence of papillary and follicular thyroid cancer.
Mutations in patients with medullary thyroid cancercancer involve other parts of the RET gene (compared with papillary carcinoma). Almost all patients with the inherited form of medullary thyroid cancer in 1 in 5 cases of sporadic forms of cancer have the same mutation in the gene RET. Most patients with sporadic medullary thyroid carcinoma have acquired mutations that are present only in their tumor cells. Patients with familial medullary cancer gene mutation in RET inherit from the parent. These mutations are present in every cell of the body and can be detected by investigating DNA blood cells.