About KRAS / Kirsten Rat Sarcoma Viral Oncogene:
The KRAS (Kirsten Rat Sarcoma Viral) gene belongs to a class of genes which is named oncogenes. These genes were first identified in rats in the 1980s. The K-Ras protein is also known as the GTPase.
It converts GTP molecules into another molecule, the GDP. When it transmits signals, it binds to a molecule of GTP. if they mutate, they can infect other cells and turn them cancerous. These oncogenes include HRAS and NRAS and work within cell divisions and destruction of cells. Many cancers are connected to mutations of genes. Mutations in this gene are found in nearly all types of pancreatic cancerous tumors, 90% of cases, as well as some colorectal and lung cancers. Within the KRAS gene, protein is found which assists with tissue signaling which is where it is associated with the growth of tumors. KRAS molecules can switch on and off and will bind to GTP in an active state. It also has an intrinsic enzymatic activity. This converts the terminal phosphate of the nucleotide to GDP.
It also produces the P19 which is a tumor suppressor gene. It can activate cellular apoptosis in the p53 tumor suppressor gene. In many cancers the KRAS gene is activated but this is found less in melanoma and carcinoma. Understanding the KRAS biology is allowing scientists to further develop anti-cancer treatments. It is believed that those with the KRAS mutations do not respond well to chemotherapy. KRAS mutations can be tested by evaluating the KRAS gene in tumor tissue from a biopsy.