BACKGROUND Colorectal cancer is frequent in the developed countries, with a cancer-specific mortality rate of 33%. Different biomarkers are associated with overall survival and the prediction of monoclonal treatment effectiveness. The presence of mutations in the K-ras oncogene alters the response to target therapy with cetuximab and could be an independent prognostic factor. AIMS To analyze ...

The activation of the cHa-ras oncogene in the EJ/T24 bladder carcinoma cell line was compared with the activation of the same gene in the rat-derived Harvey murine sarcoma virus. The results indicate that, like the human oncogene, the Harvey murine sarcoma virus-borne ras gene owes its oncogenic capacity to point mutations in coding sequences rather than to the alteration in transcriptional con...

The Ras oncogene of silkworm pupae (Bras2) may belong to the Ras superfamily. It shares 77% of its amino acid identity with teratocarcinoma oncogene 21 (TC21) related ras viral oncogene homolog-2 (R-Ras2) and possesses an identical core effector region. The mRNA of Bombyx mori Bras2 has 1412 bp. The open reading frame contains 603 bp, which encodes 200 amino acid residues. This recombinant BmBr...

The KRAS/ K-RAS oncogene is crucially involved in human cancer. The term "oncogene" -- i.e., a gene able to transform a normal cell into a tumor cell - was introduced in 1969, but the word was not used in the human carcinogenesis literature until much later. Transforming Kras and Hras oncogenes from the Kirsten and Harvey sarcoma viruses were not identified until the early 1980s due to the comp...

A plasmid containing the transforming Ha-ras gene and designated pT24-C3 was methylated in vitro using the sequence-specific bacterial methyltransferases HpaII and HhaI. Aliquots of the plasmid were methylated by the single enzymes or by the two enzymes simultaneously (double methylation). The transforming activity of the treated plasmids was assayed in the standard transfection assay on NIH-3T...

Several tumor-derived oncogenes have been shown to independently act as complete carcinogens following transfection into target cells from established tissue culture lines. However, the number and types of oncogenes required to transform primary cultures of normal mammalian cells is unclear. To clarify this issue in a simplified model system, we transfected genomic DNA from a naturally occurrin...

We study the transforming ability of X-rays in multistep carcinogenesis by irradiating primary rat cells which contain transfected c-myc oncogene. X-irradiation induces fully transformed phenotypes, including anchorage-independent growth and tumor formation in nude mice. Of seven foci examined, five exhibited an A to G conversion in codon 61 of the N-ras oncogene. Another transformed isolate ha...

Considerable data support the idea that oncogene-induced senescence remains a barrier that needs to be overcome for malignant transformation of melanocytes. Human nevi stain positive for the senescence-associated β-galactosidase marker, suggesting that cells have lost their proliferative capacity. Most nevi harbor B-RAF or N-RAS mutations, implying that they are growth arrested via oncogene-ind...

The AP-1 transcription factor plays an essential role in cell proliferation and tumorigenesis. It was previously shown that the fra-1 gene product is upregulated by various oncogenes and is involved in the in vitro and in vivo transformation of thyroid cells. Here we show that the ras oncogene-dependent accumulation of Fra-1 is mediated by a positive feedback mechanism which requires both trans...

The basal level of fibronectin (FN) biosynthesis is greatly reduced in N-ras-transformed human fibrosarcoma HT1O8O cells when compared with normal fibroblasts. The rate of FN biosynthesis can be significantly increased in HT1O8O cells by the synthetic glucocorticoid dexamethasone, which has been shown to act by selectively stabilizing the FN message (D. C. Dean, R. F. Newby, and S. Bourgeois, J...