Tumors of the stomach

There are two distinct types of tumors: benign and malignant. Both types of tumors share a number of general characteristics, the broadest being that they are an abnormal proliferation of cells. The main difference between the two types is what happens once the tumor has started growing. In a benign tumor, the proliferated cells stay in one location where they do not impact or spread to other surrounding tissues. Malignant tumors, on the other hand, are capable of spreading throughout the entire body, causing new tumors to appear. This process is called metastasis, and is a hallmark of cancerous tumors. In order to make sure that this cycle runs smoothly, there are a series of checkpoints that the cell reaches to ensure that DNA replication has been completed correctly and that the cell is of correct size. These checkpoints include an un-replicated DNA checkpoint, a spindle assembly checkpoint, a chromosome-segregation checkpoint, and various DNA damage checkpoints. Table 1 below describes different cell cycle checkpoints and their various purposes. In mammalian organisms, the cell cycle is regulated through interactions of cyclin-dependent kinases (CDKs) and cyclins.In the case of tumors, the cells display a level of abnormal growth. In most cases, this abnormal growth comes from an error in the cell cycle checkpoints. There are three general errors that occur within the cell cycle to cause abnormal cell growth. The first error is unscheduled proliferation, essentially refers to the cell continuing to grow and divide without the proper signaling from mitosis. Genomic instability, the second error, refers to mutations within the genome which causes errors in the replication or repair of the gene. Lastly, chromosomal instability is caused by mutations which disrupt the normal segregation of chromosomes in mitosis or meiosis. == Tumor growth in the stomach ==

Although it is possible to have a tumor that is benign, in the case of gastric tumors, only about 5-10% end up being non-cancerous. With that being the case, It is very important to learn the causes of stomach tumors, risk factors, and their signs and symptoms. Origins of gastric tumors Unfortunately, the early anatomical changes in the lining of the stomach that lead to cancer are rarely noticeable. The lining of the stomach is made up of a simple columnar epithelium which folds into what are called gastric glands. Within these glands are four different cell types: goblet cells, parietal cells, chief cells, and enteroendocrine cells. Mutations in any of these cell types can begin the process of uncontrolled cell proliferation, ultimately leading to the formation of a tumor. It is also important to note that depending on where in the stomach the tumor starts, signs and symptoms as well as treatment options may differ. Types of gastric tumors Source: • Adenocarcinoma • Primary Gastric Lymphoma • Gastrointestinal Stromal Tumor (GIST) • Neuroendocrine (Carcinoid) Tumors Risk factors • Smoking • Helicobacter pylori infection. • Diet low in fruits and vegetables. • Diet high in salt and nitrates. • Polyps • Genetic alterations – p53 mutation, micro-satellite instability, E-cadherin gene • Previous radiation • Pernicious anaemia Signs and symptoms Source: • Dysphagia • Indigestion • Nausea • Vomiting • Vomiting blood • Abdominal pain • Loss of appetite • Abdominal swelling • Passing black stool == References ==