Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “KRAS mutation”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 163 records · Page 9Linked to original sources
PubMed2026

Real-World Treatment Patterns and Clinical Outcomes After First-Line Therapy in Patients with KRAS G12C-Mutant Advanced Non-Small-Cell Lung Cancer in the United States.

BACKGROUND: Approximately 13% of NSCLC cases have KRAS G12C mutations. As therapeutic strategies targeting KRAS G12C-mutant NSCLC evolve, it is important to understand clinical presentation and current outcomes for these patients. METHODS: This retrospective study used data from two US nationwide databases, an electronic health records (EHR) database and a clinico-genomic database (CGDB) of EHR data linked to data from comprehensive genomic profiling tests. Eligible patients had advanced NSCLC, initiated first-line therapy from August 2018 to December 2022, and had KRAS test results. Clinicopathologic characteristics, treatments, real-world progression-free survival (rwPFS), and overall survival (OS) were analyzed. RESULTS: There were 1227 patients with KRAS G12C-mutant NSCLC in the EHR database and 447 in the CGDB. First-line regimen was platinum-based chemotherapy plus pembrolizumab for 46% and pembrolizumab monotherapy for 20%. Less than 40% of patients received second-line therapy. Median (95% CI) OS for KRAS G12C-mutant NSCLC patients in the EHR was 17.0 (15.2-18.9) months. Variables significantly associated with shorter OS included PD-L1 <1%, brain metastases, STK11 co-mutation, and poor performance status. Patients treated with platinum-based chemotherapy plus pembrolizumab had median rwPFS of 5.3 (4.5-7.3) months and OS of 12.8 (11.1-17.3) months in the CGDB; median OS was 15.6 (12.5-18.6) months in the EHR. Patients with PD-L1 &#x2265; 50% treated with pembrolizumab monotherapy had median rwPFS of 4.6 (3.0-15.6) months and OS of 20.4 (10.3-38.5) months in the CGDB; median OS was 22.1 (18.7-30.7) in the EHR. CONCLUSIONS: These data provide a real-world benchmark of outcomes for patients with KRAS G12C-mutant NSCLC receiving the current standard of care and indicate an unmet need for more effective first-line therapies.

KRAS G12C↗
PubMedDate not supplied

Cancer genetics of sporadic colorectal cancer: BRAF and PI3KCA mutations, their impact on signaling and novel targeted therapies.

Novel activating mutations in sporadic colorectal cancer (CRC) have recently been identified on major kinase encoding genes such as BRAF and PI3KCA. The presence of these activating point mutations, including the well characterized KRAS oncogene mutations, represent up to 75% of cases in CRC. These genes, that have been implicated in the adenoma-carcinoma transition, cause deregulation and constitutive activation of the MAP AKT/kinase pathways, rendering growth advantages to colon tumor cells. This review focuses on the key genetic alterations underlying the cumulative effect of multiple mutations within the colon cancer cell. Moreover, the currently available and alternative treatment approaches that may target these different genetic alterations are discussed, such as the novel BRAF inhibitor. Identification of novel mutations as well as differential gene expression analyzed by microarray reveal potential targets for combined therapeutic protocols which will result in personalized treatments in the near future.

Animals↗
PubMed2025

Identification of a Highly Cooperative PROTAC Degrader Targeting GTP-Loaded KRAS(On) Alleles.

Kirsten rat sarcoma viral oncogene homologue (KRAS) is a frequently mutated oncogene in multiple types of cancer and is a high priority target for oncology drug development. There are many different KRAS mutations, including mutations that favor the GTP-loaded hydrolysis-incompetent "active" state of KRAS, KRAS(on), that can lead to tumorigenesis. However, small molecule interventions thus far have predominantly targeted single mutations of "inactive" GDP-loaded KRAS, KRAS(off), such as KRASG12C. Here, we address this gap through the development of heterobifunctional VHL-based PROTACs capable of engaging and degrading KRAS(on), thus addressing a wider range of KRAS mutations. By studying ternary complex affinity, stability, and binding modes using SPR and X-ray cocrystal structures, we identified PROTACs that exhibit high positive cooperativity in forming ternary complexes with VHL and GCP-loaded KRAS as representative of KRAS(on) variants. Degrader activity profiling in relevant cancer cells supported the discovery of ACBI4, a PROTAC which forms a highly stable and cooperative ternary complex between VHL and GTP-bound KRAS and which potently degrades KRASG12R, leading to antiproliferative effect in KRAS mutant-driven cancer cells. ACBI4 provides a new chemical tool for studying the impact of degrading KRAS(on) mutants, which is not possible with current pan-KRAS inhibitors or degraders.

Proto-Oncogene Proteins p21(ras)↗
PubMed2006

Multifocal neoplastic precursor lesions associated with lobular atrophy of the pancreas in patients having a strong family history of pancreatic cancer.

We screened 116 patients with a strong family history of pancreatic cancer using a combination of endoscopic ultrasound and computed tomography. Ten of these patients underwent surgical resection at our institution, providing an opportunity to define the morphology of pancreatic precursor lesions in patients with a strong family history of pancreatic cancer. Eight of the 10 pancreata were available and these were entirely submitted for histologic examination. The number of pancreatic intraepithelial neoplasia (PanIN) lesions and intraductal papillary mucinous neoplasms (IPMNs) were compared with age-matched controls. Parenchymal changes were defined. Selected precursor neoplasms from 6 pancreata were microdissected and analyzed for KRAS gene mutations. PanINs were significantly more common in the 8 cases (mean of 10.7% of the duct profiles, range 1.0% to 27.3%) than in the controls (mean 1.9%, range 0% to 9.2%, P<0.01). Different KRAS gene mutations were identified in separately microdissected precursor lesions in 2 of 6 cases. IPMNs were identified in 4 of the 8 cases, including 2 pancreata each having 2 distinct IPMNs. Both the IPMNs and the PanINs, even the low-grade PanIN-1 lesions, were associated with lobular parenchymal atrophy. Some individuals with a strong family history of pancreatic cancer develop multifocal, noninvasive epithelial precursor lesions of the pancreas. PanINs and IPMNs produce obstructive lobular atrophy, and this atrophy is likely the source of the chronic pancreatitis-like changes seen in these patients. The multifocal nature of familial pancreatic neoplasia suggests that surveillance of these patients is warranted after partial pancreatectomy.

Adenocarcinoma, Mucinous↗
PubMed2004

Frequent alterations of Ras signaling pathway genes in sporadic malignant melanomas.

Ras signaling is important for the intracellular transduction of mitogenic stimuli from activated growth factor receptors. We have investigated 37 sporadic malignant melanomas (15 primary cutaneous melanomas and 22 melanoma metastases) and 6 melanoma cell lines for mutations in the 3 Ras genes NRAS, KRAS and HRAS. All tumors and cell lines were additionally analyzed for mutation and expression of BRAF, which encodes a Ras-regulated serine/threonine kinase with oncogenic properties, as well as for expression of RASSF1A, which encodes a Ras-binding protein with tumor suppressor properties. Mutational analyses identified somatic NRAS mutations in 2 primary melanomas, 4 melanoma metastases and 2 cell lines. One melanoma metastasis showed a somatic KRAS mutation whereas HRAS mutations were not detected. Eight primary melanomas, 6 melanoma metastases and 4 melanoma cell lines carried BRAF mutations affecting the known hot-spot codon 599. None of the tumors or cell lines with BRAF mutation demonstrated NRAS or KRAS mutations. Real-time reverse transcription-PCR showed that 8 melanomas (3 primary tumors, 5 melanoma metastases) had reduced RASSF1A transcript levels of < or =50% relative to benign melanocytic nevi and normal skin. Three melanoma cell lines lacked detectable RASSF1A transcripts. The RASSF1A gene promoter was hypermethylated in these 3 cell lines as well as in 6 of 8 melanomas with reduced RASSF1A mRNA levels. Treatment of the cell lines with 5-aza-2'-deoxycytidine and trichostatin A resulted in demethylation of the RASSF1A promoter and re-expression of RASSF1A transcripts. Most tumors and all cell lines with RASSF1A promoter methylation additionally carried BRAF or NRAS mutations, suggesting a synergistic effect of these aberrations on melanoma growth. Taken together, 57% of the investigated melanomas and 100% of the melanoma cell lines carried mutations in either NRAS, KRAS or BRAF. In addition, 22% of the melanomas and 50% of the cell lines showed reduced RASSF1A transcript levels. Thus, alterations of Ras pathway genes are of paramount importance in the pathogenesis of sporadic melanomas.

Adult↗
PubMed2006

APC and oncogenic KRAS are synergistic in enhancing Wnt signaling in intestinal tumor formation and progression.

BACKGROUND & AIMS: Synchronous activation of the Wnt signaling pathway, mostly because of loss of function of the APC tumor suppressor, and of the oncogenic KRAS-signaling pathway is very frequent in colorectal cancer and is associated with poor prognosis. METHODS: We have generated a compound transgenic mouse model, KRAS(V12G)/Apc(+/1638N), to recapitulate the human disease and compared it with single transgenic littermates. RESULTS: Compound mutant mice are characterized by a 10-fold increase in tumor multiplicity and by accelerated tumor progression, resulting in strongly enhanced morbidity and mortality. Tumors from compound mutant mice proliferate faster and show decreased levels of apoptosis. Several lines of evidence indicate that the observed increase in tumor multiplicity and malignant transformation is caused by the synergistic activation of Wnt signaling in cells with oncogenic KRAS and loss-of-function Apc mutations. Activated KRAS is known to induce tyrosine phosphorylation of beta-catenin, leading to its release from E-cadherin at the adherens junction. This results in an increased beta-catenin pool in the cytoplasma, its subsequent translocation to the nucleus, and the transcriptional activation of Wnt downstream target genes. Accordingly, intestinal tumors from KRAS(V12G)/Apc(+/1638N) mice show a significant increase in cells with nuclear accumulation of beta-catenin when compared with Apc(+/1638N) animals. Moreover, Apc/KRAS-mutant embryonic stem cells show a significantly enhanced beta-catenin/T-cell factor-mediated transcriptional activation, accompanied by increased beta-catenin nuclear localization. CONCLUSIONS: This KRAS-induced increase in Wnt/beta-catenin signaling may enhance the plasticity and self-renewal capacity of the tumor, thus resulting in the drastically augmented tumor multiplicity and malignant behavior in compound mutant animals.

Adenomatous Polyposis Coli Protein↗
PubMed1994

Genetic analysis is consistent with the hypothesis that NF1 limits myeloid cell growth through p21ras.

Children with neurofibromatosis, type 1 (NF-1) are at increased risk of developing malignant myeloid disorders and their bone marrows frequently show loss of the normal allele of the NF1 tumor-suppressor gene. NF1 encodes a protein called neurofibromin, which accelerates guanosine triphosphate (GTP) hydrolysis on the p21ras (Ras) family of signaling proteins. We used a genetic approach to test the hypothesis that NF1 negatively regulates myeloid cell growth through its effect on Ras. This model predicts that, if RAS mutations and loss of NF1 function deregulate myeloid growth by the same biomechanical mechanism, then activating RAS mutations will be restricted to children with malignant myeloid disorders who do not have NF-1. We studied 71 children, including 28 with bone marrow monosomy 7 syndrome (Mo7), 35with juvenile chronic myelogenous leukemia (JCML), three with other forms of preleukemia, and five with acute myelogenous leukemia (AML), for activating mutations of KRAS and NRAS. The incidence of RAS mutations was 21% (12 of 55) in patients without NF-1 and 0% (zero of 16) in children with NF-1 (P = .04). Among the 55 patients who did not have NF-1, we found RAS mutations in four of 27 with Mo 7, in five of 24 with JCML, in two of 3 with AML, and in a patient with myeloproliferative syndrome (MPS). These data from primary human cancer cells provide strong genetic evidence that NF1 limits the growth of myeloid cells by regulating Ras.

Alleles↗
PubMed2006

KRAS(D13) Promotes apoptosis of human colorectal tumor cells by ReovirusT3D and oxaliplatin but not by tumor necrosis factor-related apoptosis-inducing ligand.

Colorectal tumors frequently contain activating mutations in KRAS. ReovirusT3D is an oncolytic virus that preferentially kills tumor cells with an activated Ras pathway. Here we have assessed the contribution of endogenous mutant KRAS in human colorectal cancer cell lines to ReovirusT3D replication and to tumor cell oncolysis. In addition, treatment combinations involving ReovirusT3D, oxaliplatin, and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) were tested for their efficacy in tumor cell killing. The mutation status of KRAS did not predict the sensitivity of a panel of human colorectal cancer cell lines to ReovirusT3D. Virus replication was observed in all cell lines tested regardless of KRAS status and was not affected by deletion of endogenous mutant KRAS(D13). However, deletion of KRAS(D13) or p53 did reduce apoptosis induction by ReovirusT3D whereas deletion of beta-catenin(DeltaS45) had no effect. Likewise, KRAS(D13)- or p53-deficient cells display reduced sensitivity to oxaliplatin but not to death receptor activation by TRAIL. Finally, the treatment of colorectal cancer cells with ReovirusT3D combined with either oxaliplatin or TRAIL resulted in a nonsynergistic increase in tumor cell killing. We conclude that oncolysis of human tumor cells by ReovirusT3D is not determined by the extent of virus replication but by their sensitivity to apoptosis induction. Oncogenic KRAS(D13) increases tumor cell sensitivity to activation of the cell-intrinsic apoptosis pathway without affecting ReovirusT3D replication.

Apoptosis↗
PubMed2005

RAS mutation in acute myeloid leukemia is associated with distinct cytogenetic subgroups but does not influence outcome in patients younger than 60 years.

The pathogenesis of acute myeloid leukemia (AML) involves the cooperation of mutations promoting proliferation/survival and those impairing differentiation. The RAS pathway has been implicated as a key component of the proliferative drive in AML. We have screened AML patients, predominantly younger than 60 years and treated within 2 clinical trials, for NRAS (n = 1106), KRAS (n = 739), and HRAS (n = 200) hot-spot mutations using denaturing high-performance liquid chromatography or restriction fragment length polymorphism (RFLP) analysis. NRAS mutations were confirmed in 11% of patients (126/1106) and KRAS mutations in 5% (39/739). No HRAS mutations were detected in 200 randomly selected samples. Codons most frequently mutated were N12 (43%), N13 (21%), and K12 (21%). KRAS mutations were relatively overrepresented in French-American-British (FAB) type M4 (P < .001). NRAS mutation was over-represented in the t(3;5)(q21 approximately 25;q31 approximately q35) subgroup (P < .001) and underrepresented in t(15;17)(q22;q21) (P < .001). KRAS mutation was overrepresented in inv(16)(p13q22) (P = .004). Twenty-three percent of KRAS mutations were within the inv(16) subgroup. RAS mutation and FLT3 ITD were rarely coexistent (14/768; P < .001). Median percentage of RAS mutant allele assayed by quantitative RFLP analysis was 28% (N12), 19% (N13), 25% (N61), and 21% (K12). RAS mutation did not influence clinical outcome (overall/disease-free survival, complete remission, relapse rate) either for the entire cohort or within cytogenetic risk groups.

Acute Disease↗
PubMed2026

Genomic Analysis and Clinical Correlation of Non-Small Cell Lung Cancer with Special Reference to Brain Metastasis.

BACKGROUND: Next-generation sequencing (NGS) has improved genomic analysis depth in precision oncology. This study analyzed genomic biomarker testing in stage IV NSCLC, focusing on brain metastasis and clinicopathological correlations. OBJECTIVE: To study molecular markers and clinicopathological correlations in stage IV NSCLC patients, with and without brain metastasis. METHODS: A total of 169 stage IV NSCLC patients were studied from April 2023 to May 2025. Demographic data, clinical presentations, and mutation analyses were assessed using NGS on tissue blocks or liquid biopsies. RESULTS: Among 169 patients, 41.42% (n = 70) had brain metastasis (NSCLC-BM), while 58.58% (n = 99) had no brain metastasis (mNSCLC). Median ages were 51.5 and 56 years, respectively. Adenocarcinoma comprised 95.27% (n = 161) of cases. The cerebral hemisphere was the most common intracranial metastatic site, while skeletal involvement was the most common extracranial site. Headache was the predominant neurological symptom. EGFR mutations were the most common overall. EGFR > TP53 > ALK > other mutations were observed in NSCLC-BM, while EGFR > TP53 > KRAS > other mutations were seen in mNSCLC. Mutation analysis stratified by smoking history (&#x3c7;&#xb2;(1) = 1.347, p = 0.245) and sex (&#x3c7;&#xb2;(1) = 0.0302, p = 0.862) was not statistically significant. The benefit of gefitinib plus chemotherapy in EGFR exon 19 and exon 21 L858R mutations was greater in mNSCLC (log-rank &#x3c7;&#xb2;(1) = 10.813, p = 0.001) than in NSCLC-BM (log-rank &#x3c7;&#xb2;(1) = 3.100, p = 0.078). Median survival was 11 months (95% CI: 7.506-14.494) for NSCLC-BM versus 21 months (95% CI: 8.365-33.635) for mNSCLC, with a statistically significant difference (log-rank &#x3c7;&#xb2;(1) = 8.639, p = 0.003). CONCLUSION: NSCLC-BM showed higher genomic biomarker enrichment (80% vs. 68.68%) but poorer outcomes than mNSCLC. EGFR was the most common targetable mutation, followed by ALK in NSCLC-BM and KRAS in mNSCLC.

Humans↗
PubMed2006

Molecular pathology of epithelial ovarian cancer.

Ovarian cancer is the most lethal gynaecological malignancy and it most commonly occurs in postmenopausal women. Ninety per cent of ovarian cancers are derived from the ovarian surface epithelium and these neoplasms are classified into serous, mucinous, endometrioid, clear-cell and transitional-cell types. The molecular pathology of ovarian carcinomas is heterogeneous and involves various putative precursor lesions and multiple pathways of development. The most common subtype, high-grade serous carcinoma, is characterized by p53 mutations, and BRCA1 and/or BRCA2 dysfunction. It most likely arises from epithelium within inclusion cysts or from the surface of the ovary. In contrast, low-grade serous carcinomas are characterized by KRAS or BRAF mutations and appear to arise via an adenoma-borderline-carcinoma sequence. Similarly, mucinous carcinomas have KRAS mutations and probably develop via an adenoma-borderline-carcinoma sequence. Low-grade endometrioid carcinomas, however, are characterized by mutations in PTEN and CTNNB1, and microsatellite instability, and may arise from ovarian endometriosis or borderline endometrioid tumours. High-grade endometrioid carcinomas have similar changes to high-grade serous carcinomas. Clear-cell carcinomas are characterized by mutations of TGFbetaR2 and over-expression of HNF-1beta, and probably arise from ovarian endometriosis. The molecular changes in transitional-cell carcinomas of the ovary remain largely unknown. The identified molecular changes and pathways of development in epithelial ovarian cancer will facilitate the rationalized development of new diagnostic modalities and tailored therapies for this malignancy.

BRCA1 Protein↗
PubMed2006

Genetic and epigenetic profiling in early colorectal tumors and prediction of invasive potential in pT1 (early invasive) colorectal cancers.

Morphologically, early colorectal tumors are divided into two groups, protruded-type tumors and flat-type tumors. Although some studies have shown genetic alterations in protruded-type tumors, little is known about genetic and epigenetic alterations in flat-type tumors, as well as pT1 (early invasive) colorectal cancers (CRCs). In the current study, we compared the frequencies of genetic and epigenetic alterations of the RAS-RAF and Wnt signaling pathways in flat-type and protruded-type tumors. In addition, we investigated the relationship between those alterations and invasive potential of pT1 CRCs. Methylations of RASSF2, O-6-methylguanine-DNA methyltransferase (MGMT), Wnt inhibitory factor-1 (WIF-1), EPHB2, CDKN2A and MLH1 were detected in 44.3, 30.3, 81.4, 7.5, 43.6 and 13.4% of the 307 early colorectal tumors, respectively. Mutations of KRAS, BRAF, catalytic subunit alpha of phosphatidylinositol 3'-kinase (PIK3CA) and beta-catenin were detected in 25.4, 4.6, 1.6 and 9.4% of those tumors, respectively. Methylations of MGMT, WIF-1 and CDKN2A were detected in significantly higher percentages of protruded-type tumors than in flat-type tumors. Mutation of at least one gene was detected in a significantly higher percentage of flat-type tumors than in protruded-type tumors. RASSF2 methylation was correlated significantly with KRAS, BRAF or PIK3CA mutation. Multiple logistic analysis showed that lymphatic invasion and RASSF2 methylation with KRAS, BRAF or PIK3CA mutation were independent risk factors for venous invasion in pT1 CRCs. In conclusion, since genetic alterations of these pathways have frequently occurred in flat-type tumors, flat-type tumors seem to have a distinct genetic profile different from that of protruded-type tumors. RASSF2 methylation with oncogenic activation is a promising biomarker for predicting invasive potential of pT1 CRCs.

Aged↗
PubMed2004

Characterization of active mitogen-activated protein kinase in ovarian serous carcinomas.

PURPOSE: Mitogen-activated protein kinase (MAPK) plays a pivotal role in signal transduction. Activation of MAPK is regulated by upstream kinases including KRAS and BRAF, which are frequently mutated in low-grade ovarian serous carcinoma. This study evaluates the expression of active MAPK in ovarian serous carcinomas, with response to treatment and survival. EXPERIMENTAL DESIGN: Expression of active MAPK was assessed by immunohistochemistry in 207 cases of ovarian serous tumors. Immunoreactivity was correlated with tumor grade, mutational status of KRAS and BRAF, in vitro drug resistance, and clinical outcome. RESULT: There was a lower frequency of expression of active MAPK in high-grade ovarian serous carcinomas as compared with low-grade serous tumors, including borderline tumors and low-grade serous carcinoma (P < 0.001). Active MAPK was present in all of the 19 low-grade tumors with either KRAS or BRAF mutations as well as in 14 (41%) of 34 tumors with wild-type KRAS and BRAF in both low- and high-grade carcinomas. Expression of active MAPK alone served as a good survival indicator in the 2-year follow-up (P = 0.037) but not in the 5-year follow-up (P = 0.145). However, a combination of expression of active MAPK and in vitro sensitivity of paclitaxel significantly correlated with a better prognosis in 5-year survival rate (P = 0.048) in patients with advanced-stage high-grade serous carcinoma. CONCLUSIONS: Active MAPK is more frequently expressed in low-grade than in high-grade ovarian serous carcinoma. Active MAPK serves as a good prognostic marker in patients with high-grade serous carcinomas.

Adult↗
PubMed2005

Frequent retention of heterozygosity for point mutations in p53 and Ikaros in N-ethyl-N-nitrosourea-induced mouse thymic lymphomas.

In agreement with Knudson's two-hit theory, recent findings indicate that the inactivation of tumor suppressor genes is not only mediated by the loss of function but also by the dominant-negative or gain-of-function activity. The former generally accompanies loss of a wild-type allele whereas in the latter a wild-type allele is retained. N-Ethyl-N-nitrosourea (ENU), which efficiently induces point mutations, reportedly leads to the development of tumors by activating ras oncogenes. Little is known about how ENU affects tumor suppressor genes and, therefore, we examined ENU-induced mutations of p53 and Ikaros in thymic lymphomas and compared these with mutations of Kras. In addition, loss of heterozygosity was examined for chromosome 11 to which both p53 and Ikaros were mapped. The frequency of point mutations in p53 and Ikaros was 30% (8/27) and 19% (5/27), respectively, comparable to that observed in Kras (33%: 9/27). In total, 14 of the 27 thymic lymphomas examined (52%) harbored mutations in at least one of these genes. One Ikaros mutation was located at the splice donor site, generating a novel splice isoform lacking zinc finger 3, Ik (F3del). Interestingly, 90% (10/11) of the tumors with point mutations retained wild-type alleles of p53 and Ikaros. Sequence analysis revealed that the most common nucleic acid substitutions were T>A (4/8) in p53, T>C (4/5) in Ikaros and G>A/T (8/9) in Kras, suggesting that the spectrum of mutations was gene dependent. These results suggest that point mutations in tumor suppressor genes without loss of the wild-type allele play an important role in ENU-induced lymphomagenesis.

Animals↗
PubMed2006

Exclusive mutation in epidermal growth factor receptor gene, HER-2, and KRAS, and synchronous methylation of nonsmall cell lung cancer.

BACKGROUND: Both genetic and epigenetic changes in nonsmall cell lung cancer (NSCLC) are known to be a common event. METHODS: Mutations in the epidermal growth factor receptor gene (EGFR), HER-2, and KRAS and the methylation profile of 9 genes for NSCLC were analyzed and correlated with clinical and histologic data. RESULTS: Thirty-nine EGFR, 4 HER-2, and 6 KRAS mutations were found in 150 NSCLC cases, with the methylation percentages of the genes ranging from 13% to 54%. Most mutations were present in adenocarcinomas, but mutations of the 3 genes were never found to be present in individual tumors. The frequency of methylation for all the genes was correlated with the Methylation Index, a reflection of the overall methylation pattern (all genes, P< or = .01), supporting the presence of the CpG island methylator phenotype (CIMP) in NSCLC. On the basis of the methylation profile, CRBP1 and CDH13 methylation were good indicators of CIMP in NSCLC, and were correlated with a poorer prognosis in adenocarcinomas. Mutations in EGFR, HER-2, and KRAS were found to be present exclusively, whereas methylation tended to be present synchronously. A comparison of mutation and methylation demonstrated that the EGFR mutation had an inverse correlation with methylation of SPARC (secreted protein acidic and rich in cysteine), an extracellular Ca2+-binding matricellular glycoprotein associated with the regulation of cell adhesion and growth, and the p16INK4A gene. CONCLUSIONS: The findings of the current study suggest that adenocarcinoma cases with CIMP have a poorer prognosis than adenocarcinoma cases without CIMP, and the EGFR mutation was shown to have an inverse correlation with methylation of SPARC and the p16INK4A gene in NSCLC.

Adult↗
PubMed2006

BRAF mutations are associated with distinctive clinical, pathological and molecular features of colorectal cancer independently of microsatellite instability status.

BACKGROUND: BRAF is a member of RAF family of serine/threonine kinases and mediates cellular responses to growth signals through the RAS-RAF-MAP kinase pathway. Activating mutations in BRAF have recently been found in about 10% of colorectal cancers, with the vast majority being a V600E hotspot mutation. The aim of the present study was to evaluate the clinical, pathological and molecular phenotype of colorectal tumors with BRAF mutations. RESULTS: Mutations in BRAF were identified in 8% (23/275) of colorectal cancers. They were 5-10-fold more frequent in tumors with infiltrating lymphocytes, location in the proximal colon, poor histological grade and mucinous appearance (P < 0.002 for each). Tumors with BRAF mutation were also 10-fold more likely to show microsatellite instability and frequent DNA methylation (P < 0.0001) compared to tumors without this mutation. The characteristic morphological features of tumors with BRAF mutation (infiltrating lymphocytes, poor grade, mucinous) remained after stratification according to microsatellite instability and methylator phenotypes. Mutations in BRAF were mutually exclusive with mutations in KRAS but showed no clear association with the presence of TP53 mutation. CONCLUSION: BRAF mutation identifies a colorectal cancer subgroup with distinctive phenotypic properties independent of microsatellite instability status and thus could be a valuable marker for studies into the clinical properties of these tumors.

Adaptor Proteins, Signal Transducing↗
PubMed2006

Chromosomal changes in colorectal adenomas: relationship to gene mutations and potential for clinical utility.

Although the occurrence of both chromosomal aberrations and specific gene mutations in colorectal tumorigenesis is firmly established, the relationship between these different forms of genetic abnormality remains poorly understood. We have previously demonstrated, in colorectal adenocarcinomas, that mutations of APC, KRAS, and TP53 are each specifically associated with certain chromosomal aberrations. Using comparative genomic hybridization and mutational analysis of APC, KRAS, and TP53 to evaluate 78 colorectal adenomas, we have shown that several of the significant relationships between gene mutations and chromosomal abnormalities reported in colorectal adenocarcinomas also exist at the adenomatous stage. KRAS mutation correlated with 12p gain (P < 0.001) and TP53 mutation with both 20q gain and 18q loss (P = 0.03 for both). In addition, we have identified two chromosomal aberrations, gain of 13q and loss of 11q, that correlate with the presence of synchronous adenomas (P = 0.049 and P = 0.03, respectively) and several chromosomal changes (20p+, 20q+, 17p-, and 18q-) that are related to the onset of high-grade dysplasia. These data strengthen our previous contention that the co-occurrence of specific gene mutations and chromosomal changes is not random and significant relationships do exist. Our findings also raise the possibility that certain chromosomal aberrations may act as important clinical biomarkers.

Adenoma↗