Mechanism
Pathogenesis
Large scale studies such as The Cancer Genome Atlas (TCGA) have systematically characterized recurrent somatic alterations likely driving lung adenocarcinoma initiation and development. Gene mutations and copy number alterations
Since smoking is a strong mutagenic factor, lung adenocarcinoma is one of the tumor types with the highest number of mutations. Common somatic mutations in lung adenocarcinoma affect many oncogenes and tumor suppressor genes, including TP53 (mutated in 46% of cases), EGFR (27%), KRAS (32%), KEAP1, STK11 and NF1. EGFR and KRAS mutations tend to appear in a mutually exclusive fashion. KRAS mutations are associated with smoking habits, whereas EGFR mutations occur more frequently in females, people of Asian ethnicity and never-smokers.Copy number amplifications in oncogenes such as TERT, MDM2, EGFR, MET, and MYC have been reported, as well as deletions of tumor suppressor genes such as CDKN2A.Frequent alterations occur in genes belonging to the receptor tyrosine kinase pathway, of which EGFR is the most prominent example. This pathway is involved in cell proliferation and survival and it is often deregulated in cancer. As a consequence, targeted therapies have been developed to inhibit mutant pathway components. Chromosomal rearrangements
Three membrane associated tyrosine kinase receptors are recurrently involved in fusions or rearrangements in adenocarcinomas: ALK, ROS1, and RET, and more than eighty other translocations have also been reported in adenocarcinomas of the lung.In ALK rearrangements, the most common partner gene is EML4. EML4-ALK fusions tend to occur in tumors that do not carry EGFR or KRAS mutations and have also a lower frequency of TP53 mutations.
Bleeding, hemorrhage, haemorrhage or blood loss, is blood escaping from the circulatory system from damaged blood vessels. Bleeding can occur internally, or externally either through a natural opening such as the mouth, nose, ear, urethra, vagina or anus, or through a puncture in the skin. Hypovolemia is a massive decrease in blood volume, and death by excessive loss of blood is referred to as exsanguination. Typically, a healthy person can endure a loss of 10–15% of the total blood volume without serious medical difficulties (by comparison, blood donation typically takes 8–10% of the donors blood volume). The stopping or controlling of bleeding is called hemostasis and is an important part of both first aid and surgery. Types
Upper head
Intracranial hemorrhage – bleeding in the skull. Cerebral hemorrhage – a type of intracranial hemorrhage, bleeding within the brain tissue itself. Intracerebral hemorrhage – bleeding in the brain caused by the rupture of a blood vessel within the head. See also hemorrhagic stroke. Subarachnoid hemorrhage (SAH) implies the presence of blood within the subarachnoid space from some pathologic process. The common medical use of the term SAH refers to the nontraumatic types of hemorrhages, usually from rupture of a berry aneurysm or arteriovenous malformation (AVM). The scope of this article is limited to these nontraumatic hemorrhages. Eyes
Subconjunctival hemorrhage – bloody eye arising from a broken blood vessel in the sclera (whites of the eyes).