page_title: Causes of cancer
section_title: Organ transplantation
hierarchical_section_title: Causes of cancer / Rare causes / Organ transplantation
caption_attribution_description: HEART-GREAT VESSELS: METASTATIC MALIGNANT MELANOMA: HEART Note the pigmented masses throughout the heart.
context_page_description: Cancer is a disease caused by genetic changes leading to uncontrolled cell growth and tumor formation. The basic cause of sporadic cancers is DNA damage and genomic instability. A minority of cancers are due to inherited genetic mutations. Most cancers are related to environmental, lifestyle, or behavioral exposures. Cancer is generally not contagious in humans, though it can be caused by oncoviruses and cancer bacteria. The term "environmental", as used by cancer researchers, refers to everything outside the body that interacts with humans. The environment is not limited to the biophysical environment, but also includes lifestyle and behavioral factors.
  Over one third of cancer deaths worldwide are potentially avoidable by reducing exposure to known factors. Common environmental factors that contribute to cancer death include exposure to different chemical and physical agents, environmental pollutants, diet and obesity, infections, and radiation. These factors act, at least partly, by altering the function of genes within cells. Typically many such genetic changes are required before cancer develops.
context_section_description: The development of donor-derived tumors from organ transplants is exceedingly rare. The main cause of organ transplant associated tumors seems to be malignant melanoma, that was undetected at the time of organ harvest. There have also been reports of Kaposi's sarcoma occurring after transplantation due to tumorous outgrowth of virus-infected donor cells.
caption: Malignant melanoma metastases in a heart.
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