whast is cancer


Cancer is the common name that receives a set of related diseases in which an uncontrolled process is observed in the division of the cells of the body. 1 According to the definition of Rupert Allan Willis , an Australian pathologist, a neoplasm is an abnormal mass of tissue whose growth exceeds that of normal tissues and is not coordinated with them, and which persists in the same excessive way even after the end of the stimulus. that gave it origin. To this definition it can be added that the abnormal mass has no purpose, preys on the host and is practically autonomous. 2 It can begin in a localized way and spread to other surrounding tissues .3 In general, it leads to thepatient’s death if the patient does not receive adequate treatment. More than one hundred different types of cancer are known. 4 The most common are: skin , lung , breast and colorectal . 5

Cancer is mentioned in very old historical documents, among them Egyptian papyri from the year 1600 BC. C. who make a description of the disease. It is believed that the physician Hippocrates was the first to use the term carcino . 6 The use by Hippocrates of the term carcinos (‘relative to the crab’) is due to the fact that it related the abnormal growth to the body of the crab. The term cancer comes from the Greek word karkinoma , equivalent to Latin cancer . 7Cancer is the result of two successive processes, the proliferation of a group of cells, called tumor or neoplasia, and the invasive capacity that allows them to colonize and proliferate in other tissues or organs, a process known as metastasis . 8

The malignancy of cancer is variable, depending on the aggressiveness of its cells and other biological characteristics of each tumor type. In general, the behavior of cancer cells is characterized by lack of reproductive control that requires its original function, losing its primitive characteristics and acquiring others that do not correspond to them, such as the ability to invade progressively and through different routes to nearby organs ( metastasis), with growth and division beyond the normal limits of the organ, spreading through the body mainly through the lymphatic system or the circulatory system , and causing the growth of new tumors in other parts of the body away from the original location. 9

The differences between benign and malignant tumors are that the former are slow-growing, do not spread to other tissues and rarely recur after being excised, while the latter are fast-growing, spread to other tissues, recur frequently after be excised and cause death in a variable period of time, if treatment is not performed. 10 Malignant tumors have serious repercussions, since these cells consume the nutrients that other organs need. These increasing cancerous masses consume nutrients and energy. As a tumor grows, it creates blood vessels ( angiogenesis)) to feed itself, since it requires energy, so that it “kills with hunger” the organs that surround it. 11 Benign tumors may recur locally in certain cases, but usually do not metastasize remotely or kill the carrier, with some exceptions. Normal cells upon contact with neighboring cells inhibit their multiplication, but malignant cells do not have this brake. Most cancers form solid tumors, but some do not, for example leukemia . 12

Cancer can affect people of all ages, including fetuses, but the risk of suffering the most common increases with age. Cancer causes about 13% of all deaths. According to the American Cancer Society , 7.6 million people died from this disease in the world during 2007 . 13

The process by which cancer occurs ( carcinogenesis ) is caused by abnormalities in the genetic material of cells. These abnormalities can be caused by different carcinogens , such as ionizing radiation , ultraviolet radiation , chemical products from industry, tobacco smoke and pollution in general, or infectious agents such as human papilloma virus or human papillomavirus. B hepatitis . 9 Other carcinogenic genetic abnormalities are acquired during normal DNA replication, by not correcting the errors that occur during this process, or are inherited and, therefore, occur in all cells from birth and are more likely to cause the disease. There are complex interactions between genetic material and carcinogens, a reason why some individuals develop cancer after exposure to carcinogens and others do not. New aspects of cancer genetics , such as DNA methylation and microRNAs , are being studied as important factors to be taken into account due to their involvement. 14 Genetic abnormalities found in cancer cells may be a mutationpunctuality, translocation , amplification, deletion , and gain or loss of a complete chromosome

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