Our current understanding

Cancer is not one disease but an assortment of over 200 diverse diseases that can arise from all tissues and organs. For example, cancers arising from blood cells are called leukemias; those arising from organ tissues such as the liver or the lungs are called solid tumors. More than one type of cancer can originate from an organ or tissue, as is the case of Lymphomas, a group of malignancies of the lymphatic system, encompassing more than 20 related cancers, depending on the classification used. Cancers can exhibit slow growth patterns compatible with long and symptom-free survival, such as indolent lymphomas or chronic lymphocytic leukemia, or can quickly progress causing symptoms and death in only a few months, as is the case of acute myelocytic leukemia and pancreatic cancer. Likewise, some cancers quickly spread distally from the site of origin, such as colon, prostate, and lung cancer that often reach liver, bone, and brain, respectively. Others tend to invade locally as is the case of head and neck cancers. Yet, despite their heterogeneous origin, distinct clinical features, and vastly different course and outcome, the underlying genetic processes leading to their development, growth, and dissemination are similar.