Problem 2RCQ: How does pressure at the bottom of a body of water relate to... How does pressure at the bottom of a body of water relate to the weight of water above each square meter of the bottom surface? Chapter , Problem is solved.
The mutations that cause carcinoid tumors often affect the MEN1 gene, the same gene responsible for most familial neuroendocrine tumors and neuroendocrine cancers. But not much is known about exactly what causes these gene changes. Doctors do know that carcinoid tumors start out very small and grow slowly. When patients have parts of their stomach or small intestine removed to treat other diseases, taking a close look under the microscope often shows small groups of neuroendocrine cells that look like tiny carcinoids.
Causes and Risk Factors. Like all cancers, basal cell carcinoma is a result of errors, or mutations, in the DNA of affected cells. While some mutations are harmless, others dismantle the cellular pathways that control cell proliferation. In the absence of tight controls, cells overgrow to form tumors. The main cause of DNA damage in basal cell carcinoma is prolonged exposure to UV light from the sun. UV radiation is also believed to block DNA repair proteins, further allowing the proliferation of mutant cells. The following risk factors are associated with basal cell carcinoma: