The prognostic and predictive value of KRAS gene mutations in stage III colorectal cancer is controversial because many recent clinical trials have not involved a surgery-alone arm. Additionally, data on the significance of extended RAS (KRAS/NRAS) mutations in stage III cancer are not available. Hence, we undertook a combined analysis of two phase III randomized trials, in which the usefulness...

A glycine to valine substitution at codon 12 (G12V) in Kirsten-Ras (K-Ras) gene has been associated with reduced overall survival in colorectal cancer patients; however, the effect of other K-Ras mutations than G12V still remains unclear. Therefore, we investigated the role of different K-Ras mutations on overall survival in a homogeneous, large patient cohort with standardized therapy and unif...

PURPOSE To improve the selection of advanced colorectal cancer patients to panitumumab by optimizing the assessment of RAS (KRAS-NRAS) mutations. EXPERIMENTAL DESIGN Using a centralized pyrosequencing RAS assay, we analyzed the tumors of 94 patients, wild-type for KRAS mutations (codons 12 to 13) by Sanger sequencing (SS), treated with panitumumab. RESULTS By SS analysis, 94 (62%) of 152 pa...

Using polymerase chain reaction and sequence-specific oligonucleotide hybridization, the frequency of three ras oncogene mutations (N-ras, Ha-ras, and K-ras) in thyroid tumors (25 adenomas, 16 follicular carcinomas, and 22 papillary carcinomas) was investigated in both iodide-deficient and iodide-sufficient areas. The ras oncogene mutation rate was significantly higher in the iodide-deficient a...

AIMS To investigate the prevalence of K-ras codon 12 point mutations in ampullary neoplasms, to explore their clinical usefulness, and to test whether the detection of these mutations could be used to identify ampullary malignancies at an early stage. METHODS Forty one tumour specimens from 28 patients with ampullary neoplasms were analysed for activating point mutations in K-ras codon 12 usi...

The prevalence and significance of genetic abnormalities in older patients with acute myeloid leukemia (AML) are unknown. Polymerase chain reactions and single-stranded conformational polymorphism analyses were used to examine 140 elderly AML patients enrolled in the Southwest Oncology Group study 9031 for FLT3, RAS, and TP53 mutations, which were found in 34%, 19%, and 9% of patients, respecti...

Pancreatic adenocarcinoma is thought to arise from a noninvasive neoplastic precursor, the pancreatic intraductal lesion (PIL). Mutations of the K-ras gene are known to occur in PILs, but their high prevalence among PILs within the general population probably limit the use of K-ras as a marker of eventual clinical risk. In search of genetic constellations that might indicate the progression of ...

PURPOSE Bladder cancer is the fifth most common malignancy in men in Western society. We determined RAS codon 12 and 13 point mutations and evaluated mRNA expression levels in transitional cell carcinoma cases. MATERIALS AND METHODS Samples from 30 human bladder cancers and 30 normal tissues were analyzed by polymerase chain reaction/restriction fragment length polymorphism and direct sequenc...

Activating K-ras mutations are found in approximately 90% of pancreatic carcinomas and may contribute to the poor prognosis of these tumors. Because radiotherapy is frequently used in pancreatic cancer treatment, we assessed the contribution of oncogenic K-ras signaling to pancreatic cancer radiosensitivity. Seven human pancreatic carcinoma lines with activated K-ras and two cell lines with wil...