Recently, an alternative pathway of tumorigenesis has been identified in the colorectum associated with serrated precursor lesions, variable levels of microsatellite instability (MSI-V), and driven in part by activating mutations in the BRAF proto-oncogene (V599E).
Like the previously reported mutually exclusive relationship between BRAF mutation and other Ras pathway components such as RET/PTC rearrangement, a mutually exclusive relationship also exists between BRAF mutation and RASSF1A methylation in thyroid tumorigenesis.
Our results show that BRAF, KRAS and PIK3CA mutations occur prior to malignant transformation demonstrating that these oncogenic alterations are primary genetic events in colorectal carcinogenesis.
Activating B-Raf mutations arise in 60% to 70% of human melanomas and are thought to play a vital role in tumorigenesis, although how this occurs remains poorly understood.
These data suggest that the BRAFV600E mutation is not the target gene for abnormal MMR in carcinogenesis in patients with sporadic endometrial cancer, unlike in colon cancer.
Since high expression of neu mRNA is evident in the hamster Schwann cell at the late gestational and neonatal stages, transplacental administration of N-nitroso-N-ethylurea is considered to interact directly to carcinogenesis of the hamster Schwann cell through neu gene mutation.
Activating KRAS mutations are common in ovarian carcinomas of low histological grade, less advanced clinical stage and mucinous histological subtype, and form part of the distinct molecular alterations associated with type I tumors in the dualistic model of ovarian carcinogenesis.
Here, we report that Mps1/AKT and B-Raf(WT)/ERK signaling form an auto-regulatory negative feedback loop in melanoma cells; notably, oncogenic B-Raf(V600E) abrogates the negative feedback loop, contributing the aberrant Mps1 functions and tumorigenesis.
Pancreatic and colorectal carcinomas frequently express oncogenic/mutant K-Ras that contributes to both tumorigenesis and clinically observed resistance to radiation treatment.
These results suggested that mutation of the p16/CDKN2 gene was a common factor in the development of human MMMs and ACCs, while this gene may be correlated with development and/or progression of a subtype and play a role in the oncogenesis of these cancers.
The aim of the present study was to evaluate the methylation status of three cancer-related genes, APC2, p14ARF, and ECAD in colorectal carcinogenesis and their association with the mutational status of BRAF and KRAS among Iranian colorectal cancer patients.
Our findings provide cogent evidence that mutations of BRAF and KRAS occur in the epithelium of cystadenomas adjacent to SBTs and strongly suggest that they are very early events in tumorigenesis, preceding the development of SBT.
Our findings provide cogent evidence that mutations of BRAF and KRAS occur in the epithelium of cystadenomas adjacent to SBTs and strongly suggest that they are very early events in tumorigenesis, preceding the development of SBT.
We propose that continuously activated BRAF(V600E) signaling may be a possible mechanism for the deregulation of Mps1 stability and kinase activity in human tumors, and that persistent phosphorylation of Mps1 through BRAF(V600E) signaling is a key event in disrupting the control of centrosome duplication and chromosome stability that may contribute to tumorigenesis.
The data suggest that coexpression of BRAF(V600E) and KRAS(G12D) in early tumorigenesis leads to negative selection due to oncogene-induced senescence.
Thus, we conclude that p53 deficiency and KRAS mutation activate the NF-κB signaling to control chemoresistance and tumorigenesis, and that the status of p53 and KRAS may be considered for the targeted therapy against NF-κB in lung cancer patients.