The normal cell type most closely associated with MM cells is generally taken to be either an activated memory B cell or the precursor to plasma cells, the plasmablast.The immune system keeps the proliferation of B cells and the secretion of antibodies under tight control. When chromosomes and genes are damaged, often through rearrangement, this control is lost. Often, a promoter gene moves (or translocates) to a chromosome, where it stimulates an antibody gene to overproduction. A chromosomal translocation between the immunoglobulin heavy chain gene (on chromosome 14, locus q32) and an oncogene (often 11q13, 4p16.3, 6p21, 16q23 and 20q11) is frequently observed in people with multiple myeloma. This mutation results in dysregulation of the oncogene which is thought to be an important initiating event in the pathogenesis of myeloma. The result is a proliferation of a plasma cell clone and genomic instability that leads to further mutations and translocations. The chromosome 14 abnormality is observed in about 50% of all cases of myeloma. Deletion of (parts of) chromosome 13 is also observed in about 50% of cases. Production of cytokines (especially IL-6) by the plasma cells causes much of their localised damage, such as osteoporosis, and creates a microenvironment in which the malignant cells thrive. Angiogenesis (the generation of new blood vessels) is increased. The produced antibodies are deposited in various organs, leading to kidney failure, polyneuropathy, and various other myeloma-associated symptoms.
Endemic goiter is a type of goitre that is associated with dietary iodine deficiency. Cause
Some inland areas where soil and water lacks in iodine compounds and consumption of marine foods is low are known for higher incidence of goitre. In such areas goitre is said to be "endemic". Prevention
This type of goiter is easily preventable. In most developed countries regulations have been put into force by health policy institutions requiring salt, flour or water to be fortified with iodine. Treatment
Treatment of endemic goiter is medical with iodine and thyroxine preparations. Surgery is only necessary in cases where complicated by significant compression of nearby structures. References


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