BRAF Mutation Rate Research Articles

MUTATIONAL STATUS AND SOME CLINICO-MORPHOLOGICAL FEATURES OF CUTANEOUS MELANOMA

Cutaneous melanoma is characterized by molecular heterogeneity. The work is devoted to the analysis of mutational status of genes involved in MAPK signaling in primary and metastatic cutaneous melanoma for the detection of tumor sensitivity to the specific targeted therapy as well as possible links of genetic alterations in cutaneous melanoma with some clinical and morphological features. BRAF, NRAS and KIT mutations were found in 60.6%, 13.8% and 1% of cutaneous melanoma cases correspondingly. Mutational status of cutaneous melanoma is differed depending on tumor localization, chronic UV insolation and patients’ age. Thus the rate of the BRAF mutation in melanomas of trunk and extremities (64.7%) was higher than in melanomas of face and head (42.8%). The rate of BRAF mutation was shown to be not associated with pigmentation and tumor growth while NRAS mutation frequency in amelanotic melanoma was lower and in noddle melanoma - higher if compared with pigmented cutaneous melanoma in the radial growth phase. The trend in the association of mutations with melanoma histological type was shown for the first time, the highest rate of BRAF mutation was found in epithelioid melanoma. The obtained results are important for the treatment of cutaneous melanoma as mutational status determines the sensitivity of metastatic melanoma to specific targeted therapy in patients with BRAF, NRAS and KIT mutations.

Correlations of IGF-1R and COX-2 Expressions with Ras and BRAF Genetic Mutations, Clinicopathological Features and Prognosis of Colorectal Cancer Patients.

This case-control study aims to investigate the correlations of insulin-like growth factor receptor 1 (IGF-1R) and cyclooxygenase 2 (COX-2) expressions with Ras and BRAF genetic mutations, clinicopathological features and prognosis of colorectal cancer (CRC) patients. A total of 213 CRC patients (case group) and 200 healthy individuals (control group) were selected from our hospital. Ras (K-Ras/N-Ras) and BRAF genetic mutations were detected by direct sequencing. The positive expression rates of IGF-IR and COX-2 in CRC and normal tissues were detected using immunohistochemistry. RT-qPCR and Western blotting were applied to detect the mRNA and protein expressions of IGF-IR and COX-2 in CRC tissues and normal tissues. Total mutation rate of N-Ras, BRAF and K-Ras in case group were 5.2%, 12.2% and 47.4%, respectively. The expressions of IGF-IR and COX-2 were higher in CRC tissues with Ras and BRAF mutations than in those without. CRC tissues with Ras mutation showed higher COX-2 expression than those with BRAF mutation. IGF-IR and COX-2 expressions were correlated to infiltration degree, lymphatic metastasis (in CRC tissues with and without Ras and BRAF mutations), and Dukes stages (only in CRC tissues with Ras and BRAF mutations). CRC patients with negative expressions of IGF-IR and COX-2 had significantly higher accumulative survival rate and longer mean survival duration than those with positive expressions of IGF-IR and COX-2. These findings indicate that IGF-1R and COX-2 expressions may be associated with Ras and BRAF genetic mutations, clinicopathological feature and prognosis of CRC patients.

Differences in mutation rates between right- and left-sided colorectal adenocarcinoma.

622 Background: Recent reports have demonstrated inferior outcomes for patients with right-sided colorectal cancer (CRC) compared to patients with left-sided disease (Schrag et al 2016, JCO 34 (suppl; abstr 3505)) as well as differences in treatment response based on disease sidedness (Venook et al 2016, JCO 34 (suppl; abstr 3504)). However, the biological and genetic underpinnings of these clinical differences are incompletely understood. Methods: We compared mutation rates among 38 genes in a retrospective review of next-generation sequencing data of CRC samples obtained in routine clinical practice at a single academic medical center. Primary location was identified via chart review. Right = cecum to transverse colon; Left = descending colon to rectum. Results: Among 293 samples (167 left-sided, 103 right, 23 synchronous or without clear primary), BRAF and CTNNB1 mutations were more prevalent in right-sided CRC. BRAF was mutated in 15.5% of right-sided CRC (95% CI: 8.5-22.5%) compared to 4.8% (CI: 1.6-8.0%) (p=0.003). CTNNB1 was mutated in 3.9% of right-sided CRC (CI: 0.2-7.6%) compared to no instances of CTNNB1 mutations in left-sided disease (p=0.01). Among right-sided CRC, there was a trend toward more KRAS mutations at 57.3% (CI: 47.7-66.8%) versus 44.9% (CI: 37.4-52.5%) and more PIK3CA mutations at 26.2% (CI:17.7-34.7%) versus 17.4% (CI: 11.6-23.1%), though these differences did not rise to the level of statistical significance. The overall rate of BRAF mutations in our sample (8.9%, CI: 5.5-12.3%) was consistent with the rate of BRAF mutations among large intestine adenocarcinomas in the COSMIC database (10.6%, CI: 10.4-10.8%), lending support to the external validity of these data. Conclusions: These differing mutation rates may implicate these genetic pathways in the mechanisms underlying the discrepant outcomes and treatment responses between right and left-sided disease described in prior studies. Further work is needed to more clearly elucidate genetic difference between right and left-sided CRC, as well as the mechanistic relationship between these mutations and prognosis.

Abstract IA05: The serrated pathway of colorectal tumorigenesis

Abstract IA05: The serrated pathway of colorectal tumorigenesis

PUB079 EGFR and BRAF Mutation Detection in FFPE Samples of Lung Adenocarcinoma

EGFR-TKIs have been the standard first-line treatment for metastatic NSCLC patients with sensitive EGFR-mutants, meanwhile, other drugs target different driver mutants like BRAF-inhibitor dabrafenib has shown promising efficacy for metastatic BRAF-mutated NSCLC patients. Therefore, spotting patients carrying the targeted mutations is of great significance. However, molecular detection methods applied in clinical practice, especially detection of BRAF in NSCLC patients needs further exploration. Therefore, more sensitive and economic methods are required. We applied the CastPCR technology to the molecular detection of EGFR (del2235-2249, del2236-2250, T790M, L858R) and BRAF (V600E, G469A, D594G) mutations in 144 treatment-naive adenocarcinomas of the lung, and analyzed the association between the mutation rates and patients' clinicopathological features. EGFR mutation: 74 (51.4%, 74/144) cases were identified harboring EGFR mutations. 58 (40.3%, 58/144) carried sensitizing mutations (19Del or L858R) and 21 (14.6%, 21/144) carried resistant mutations (T790M). 10 (6.9%, 10/144) mutation-positive patients were double-mutated. EGFR mutation rate was significantly higher in female compared with that of males (60.9% v.s. 43.8%, P＜0.05), in non-smokers compared with that of smokers (62.8% v.s. 34.5%, P＜0.05). BRAF mutation:12 (8.3%, 12/144) patients were identified with BRAF mutations. 2 were V600E (16.7%, 2/12) and 10 (83.3%, 10/12) were non-V600E. Among the 10 non-V600E mutations, D594G accounted for 9 (90.0%，9/10) and G469A accounted for only 1 (10.0%, 1/10). Statistical analysis demonstrated that BRAF mutation rate was not associated with any of the clinicopathological features: age, gender, smoking status, differentiation degree, tumor size, regional lymph nodes metastasis and distant metastasis of (P≥0.05). The CastPCR technology is a robust method with high sensitivity for molecular detecting of EGFR and BRAF mutations in clinical FFPE samples.

198P Use of chemotherapy and mismatch repair deficiency testing in resected stage II colon cancer

Background Adjuvant chemotherapy for stage II colon cancer offers a small (2-3%) overall survival benefit and is not universally recommended. Currently, chemotherapy is often discussed with patients at increased recurrence risk based on histological criteria. Mismatch repair deficiency (dMMR) confers an improved prognosis and identifies patients who appear not to benefit from post-operative chemotherapy. Widespread immunohistochemistry testing in Australia began in 2013. Methods Prospective data were collected on all patients with resected stage II colon cancer between Feb-2010 to Feb-2015 across two large Australian hospitals. Rectal cancers were excluded. Data collected included patient demographics, tumour histology especially presence of high-risk features (<12 nodes, obstruction, perforation, poor differentiation, T4), dMMR testing frequency, chemotherapy use, and outcomes. Results 355 patients (56.1% female) were analysed. 25 (7.3%) received adjuvant chemotherapy (Cabrini 22/271 vs. Alfred 3/84,8% vs. 4%p = 0.22). Mean age was 77.9 years. No patient >80 years (52%) received chemotherapy. Presence of > 1 high-risk feature increased the likelihood of adjuvant chemotherapy. dMMR testing was performedon167patients(47%),mostoccurredpost-2013 (117/160vs. 50/195 patients).dMMRrateswere34.1%.2/57dMMRpatientsreceivedchemotherapy;both young(34and54years) withhigh-riskfeatures.28/355(7.8%) patientsrelapsed, including 3/25 (12%) who had received chemotherapy, and 25/330 (6.9%) who did not. 10/28(36%) ofrelapsesaredisease-freepost-resection,9(32%) alivewithmetastatic disease, and 9 deceased. An audit of familial cancer clinic referrals and BRAF mutation rate is underway. Conclusions >50%ofpatients were>80 years. Uptakeofchemotherapywaslow (7.3%).Despitethis,fewrelapseswereobserved(7.8%)and36%oftheseunderwent successful surgical salvage. dMMR testing should be performed in all stage II colon cancer patients being considered for adjuvant chemotherapy as it will identify a proportion(34.1%)ofpatientswhomaynotbenefitfromtreatment. Legal entity responsible for the study N/A Funding Alfred Hospital and Cabrini Health Disclosure All authors have declared no conflicts of interest.

Molecular spectrum of KRAS, NRAS, BRAF, PIK3CA, TP53, and APC somatic gene mutations in Arab patients with colorectal cancer: determination of frequency and distribution pattern.

The frequency rates of mutations such as KRAS, NRAS, BRAF, and PIK3CA in colorectal cancer (CRC) differ among populations. The aim of this study was to assess mutation frequencies in the Arab population and determine their correlations with certain clinicopathological features. Arab patients from the Arab Gulf region and a population of age- and sex-matched Western patients with CRC whose tumors were evaluated with next-generation sequencing (NGS) were identified and retrospectively reviewed. The mutation rates of KRAS, NRAS, BRAF, PIK3CA, TP53, and APC were recorded, along with clinicopathological features. Other somatic mutation and their rates were also identified. Fisher's exact test was used to determine the association between mutation status and clinical features. A total of 198 cases were identified; 99 Arab patients and 99 Western patients. Fifty-two point seven percent of Arab patients had stage IV disease at initial presentation, 74.2% had left-sided tumors. Eighty-nine point two percent had tubular adenocarcinoma and 10.8% had mucinous adenocarcinoma. The prevalence rates of KRAS, NRAS, BRAF, PIK3CA, TP53, APC, SMAD, FBXW7 mutations in Arab population were 44.4%, 4%, 4%, 13.1%, 52.5%, 27.3%, 2% and 3% respectively. Compared to 48.4%, 4%, 4%, 12.1%, 47.5%, 24.2%, 11.1% and 0% respectively in matched Western population. Associations between these mutations and patient clinicopathological features were not statistically significant. This is the first study to report comprehensive hotspot mutations using NGS in Arab patients with CRC. The frequency of KRAS, NRAS, BRAF, TP53, APC and PIK3CA mutations were similar to reported frequencies in Western population except SMAD4 that had a lower frequency and higher frequency of FBXW7 mutation.

Diagnostic value of BRAFV600E-mutation analysis in fine-needle aspiration of thyroid nodules: a&amp;nbsp;meta-analysis

Fine-needle aspiration (FNA) is a reliable method for preoperative diagnosis of thyroid nodules; however, about 10%–40% nodules are classified as indeterminate. The BRAFV600E mutation is the most promising marker for thyroid FNA. This meta-analysis was conducted to investigate the diagnostic value of BRAFV600E analysis in thyroid FNA, especially the indeterminate cases. Systematic searches were performed in PubMed, Web of Science, Scopus, Ovid, Elsevier, and the Cochrane Library databases for relevant studies prior to June 2015, and a total of 88 studies were ultimately included in this meta-analysis. Compared with FNA cytology, the synergism of BRAFV600E testing increased the diagnostic sensitivity from 81.4% to 87.4% and decreased the false-negative rate from 8% to 5.2%. In the indeterminate group, the mutation rate of BRAFV600E was 23% and varied in different subcategories (43.2% in suspicious for malignant cells [SMC], 13.77% in atypia of undetermined significance/follicular lesion of undetermined significance [AUS/FLUS], and 4.43% in follicular neoplasm/suspicious for follicular neoplasm [FN/SFN]). The sensitivity of BRAFV600E analysis was higher in SMC than that in AUS/FLUS and FN/SFN cases (59.4% vs 40.1% vs 19.5% respectively), while specificity was opposite (86.1% vs 99.5% vs 99.7% respectively). The areas under the summary receiver-operating characteristic curve also confirmed the diagnostic value of BRAFV600E testing in SMC and AUS/FLUS rather than FN/SFN cases. Therefore, BRAFV600E analysis can improve the diagnostic accuracy of thyroid FNA, especially indeterminate cases classified as SMC, and select malignancy to guide the extent of surgery.

Medullary carcinoma in the colorectum: a systematic review and meta-analysis

Medullary carcinoma (MC) is a very rare variant of colorectal carcinoma (CRC). Its clinicopathologic findings are not fully elucidated. The aim of this study was to investigate the clinicopathological characteristics of MC in the colorectum through a systematic review and meta-analysis. The meta-analysis examined the incidence, age, sex, site, mismatch repair deficiency (MMRd), MMR protein expression, ARID1A expression, BRAF(V600E) mutation, KRAS mutation, and survival rate of MC. The 21469 CRCs included 462 MCs in 16 eligible studies, representing an estimated incidence of MC of 0.027 (95% confidence interval [CI] 26 0.016-0.045). MC frequently occurred in female patients and in the right colon. Lymph node metastasis of MC was significantly lower than that of poorly differentiated adenocarcinoma/undifferentiated adenocarcinoma (PDA/UDA). In addition, MC had a higher MMRd rate (0.892, 95% CI 0.758-0.956), higher BRAF(V600E) mutation rate (0.652, 95% CI 0.143-0.954) and lower KRAS mutation rate (0.171, 95% CI 0.065-0.378) than PDA/UDA and conventional adenocarcinoma. Patients with MC had significantly better overall survival rate compared to patients with PDA/UDA (hazard ratio 0.441, 95% CI 0.262-0.742). However, there was no significant difference of overall survival rate between MC and conventional adenocarcinoma patients. MC predominantly occurred in females and in the right colon, and had different molecular characteristics and behaviors compared to PDA/UDA and conventional adenocarcinoma.

Significance of KRAS, NRAS, BRAF and PIK3CA mutations in metastatic colorectal cancer patients receiving Bevacizumab: a single institution experience

Background. KRAS mutation is an important predictive and prognostic factor for patients receiving anti-EGFR therapy. An expanded KRAS, NRAS, BRAF, PIK3CA mutation analysis provides additional prognostic information, but its role in predicting bevacizumab efficacy is unclear. The aim of our study was to evaluate the incidence of KRAS, NRAS, BRAF and PIK3CA mutations in metastatic colorectal cancer patients receiving first line oxaliplatin based chemotherapy with or without bevacizumab and to evaluate their prognostic and predictive significance.Methods. 55 patients with the first-time diagnosed CRC receiving FOLFOX ± bevacizumab were involved in the study. Tumour blocks were tested for KRAS mutations in exons 2, 3 and 4, NRAS mutations in exons 2, 3 and 4, BRAF mutation in exon 15 and PIK3CA mutations in exons 9 and 20. The association between mutations and clinico-pathological factors, treatment outcomes and survival was analyzed.Results. KRAS mutations were detected in 67.3% of the patients, BRAF in 1.8%, PIK3CA in 5.5% and there were no NRAS mutations. A significant association between the high CA 19–9 level and KRAS mutation was detected (mean CA 19–9 levels were 276 and 87 kIU/l, respectively, p = 0.019). There was a significantly higher response rate in the KRAS, NRAS, BRAF and PIK3CA wild type cohort receiving bevacizumab compared to any gene mutant type (100 and 60%, respectively, p = 0.030). The univariate Cox regression analysis did not confirm KRAS and other tested mutations as prognostic factors for PFS or OS.Conclusions. Our study revealed higher KRAS and lower NRAS, BRAF and PIK3CA mutation rates in the Lithuanian population than those reported in the literature. KRAS mutation was associated with the high CA 19–9 level and mucinous histology type, but did not show any predictive or prognostic significance. The expanded KRAS, NRAS, BRAF and PIK3CA mutation analysis provided additional significant predictive information.

Traditional serrated adenoma with BRAF mutation is associated with synchronous/metachronous BRAF-mutated serrated lesions.

To determine whether traditional serrated adenoma (TSA) results in an increased risk of developing subsequent serrated polyps or colorectal cancer (CRC). We recruited 111 patients with an index TSA, and analysed the pathological and molecular features of their synchronous/metachronous serrated lesions. Fifty hyperplastic polyps, 14 sessile serrated adenomas, an additional 27 TSAs and 17 CRCs were identified from 46 patients. Twenty-seven percent of TSAs showed a precursor serrated polyp in the periphery and were strongly correlated with BRAF mutation (P < 0.001). Serrated polyps occurred more commonly in patients with BRAF-mutated index TSAs than in patients with KRAS-mutated index TSAs. BRAF-mutated index TSAs were strongly associated with a right-sided location and BRAF mutation of synchronous/metachronous serrated polyps (P = 0.013 and P = 0.005, respectively). The 17 CRCs occurred more frequently in women, and were characterized by a high BRAF mutation rate (59%), a positive CpG island methylator phenotype (59%), and stable or low levels of microsatellite instability (77%). BRAF-mutated TSA is distinct from KRAS-mutated TSA in predisposing to the acquisition of subsequent serrated neoplasia. This indicates the presence of an intestinal field defect in the tumour microenvironment that results in tumour initiation and malignant progression.

Frequent BRAF mutation in early-onset colorectal cancer in Taiwan: association with distinct clinicopathological and molecular features and poor clinical outcome

BackgroundOccurrence of early-onset colorectal cancer (EOCRC) under the age of 30 is very rare and the molecular characteristics are poorly understood. A low BRAF mutation rate has been noted in...

A clinicopathologic study of diencephalic pediatric low-grade gliomas with BRAF V600 mutation.

Among brain tumors, the BRAF (V600E) mutation is frequently associated with pleomorphic xanthoastrocytomas (PXAs) and gangliogliomas (GGs). This oncogenic mutation is also detected in ~5% of other pediatric low-grade gliomas (LGGs) including pilocytic astrocytomas (PAs) and diffuse astrocytomas. In the current multi-institutional study of 56 non-PXA/non-GG diencephalic pediatric LGGs, the BRAF (V600) mutation rate is 36%. V600-mutant tumors demonstrate a predilection for infants and young children (<age 3) and have a higher tendency for multicentricity. On neuroimaging, BRAF (V600)-mutant tumors appear as nodular, yet infiltrative contrast-enhancing masses. Morphologic examination reveals a monophasic, predominantly compact and partially infiltrative architecture. Due to the lack of classic morphologic features associated with PAs, pilomyxoid astrocytomas (PMAs), or diffuse astrocytomas, 75% of the BRAF (V600)-mutant tumors could not be definitively classified on initial histopathologic evaluation. At a median follow-up of 55months, the 5-year progression-free survival (PFS) rate for BRAF (V600)-mutant diencephalic low-grade astrocytomas (LGAs) was 22±12%, shorter than BRAF (V600)-WT PAs (52±13%) but higher than PMAs (10±6%). Of note, long-term PFS was observed in several adolescent patients with BRAF (V600)-mutant tumors. In children aged 0-12years, 5-year PFS rate and median PFS in BRAF (V600)-mutant LGAs are 9±9% and 19months (95% CI 3-37months), respectively. The PFS is comparable to that in BRAF (V600)-WT PMAs (5-year PFS rate: 10±9%; median PFS: 15months, 95% CI 3-32months; p=0.96) and significantly shorter than BRAF (V600)-WT PAs (5-year PFS rate: 46±13%; median PFS: 51months, 95% CI 20-∞ months; p<0.05). In summary, diencephalic BRAF (V600)-mutant pediatric LGAs are associated with unique clinicopathologic features and have a more aggressive clinical course, especially in children under age 13. The low rate of CDKN2A deletion also suggests that these tumors are molecularly distinct from secondary pediatric high-grade gliomas.

Racial Differences in BRAF/KRAS Mutation Rates and Survival in Stage III Colon Cancer Patients.

It is unknown if, after controlling for clinicopathologic variables and treatment, racial disparities in colon cancer outcomes persist. Molecular marker analysis in North American patients comparing Asians with other races has not been reported. BRAF (V600E) and KRAS mutations were analyzed in node-positive colon cancer patients (n = 3305) treated with FOLFOX-based chemotherapy in an adjuvant trial (Alliance N0147). Race categories included Asian, black, or white. Cox models were used to estimate disease-free survival (DFS) and time to recurrence (TTR). All statistical tests were two-sided. BRAF mutation frequency in tumors from whites (13.9%) was twice that of tumors from Asians or blacks. KRAS mutation rates were highest in tumors from blacks (44.1%). KRAS/BRAF wild-type tumors were most common among Asians (66.7%) (P overall < .001). The prognostic impact of race differed by age and N stage (both P interaction < .02). Compared with whites, blacks had shorter DFS among patients younger than age 50 years (hazard ratio [HR] = 2.84, 95% confidence interval [CI] = 1.73 to 4.66) or with N1 disease (HR = 1.54, 95% CI = 1.04 to 2.29), independent of BRAF, KRAS, and other covariates. Findings were consistent using TTR as the outcome. Asians had longer DFS among N2 tumors that was partly mediated by less frequent BRAF mutation. Colon cancers from Asians have a lower rate of BRAF and KRAS mutations than blacks or whites. We report a novel interaction of race with age and N stage in node-positive disease, indicating that racial disparities in survival persist despite uniform stage and treatment in a phase III trial.

BRAF-mutated carcinomas among thyroid nodules with prior indeterminate FNA report: a systematic review and meta-analysis.

Several molecular analyses have been investigated for risk stratification of thyroid nodules, with a particular focus on the V600E mutation of the BRAF gene [BRAF(V600E)]. To date, there is no high-level evidence supporting or refuting a role for BRAF analysis in thyroid nodules with prior indeterminate cytology. To obtain more robust evidence, we reviewed and meta-analysed data from published articles. A comprehensive literature search of the PubMed/MEDLINE, Embase and Scopus databases was conducted using the terms 'BRAF', 'thyroid' and 'indeterminate'. The search was updated until March 2015, and references of the retrieved articles were also screened. Only original articles reporting BRAF mutation testing within nodules with indeterminate FNA were eligible for inclusion. The literature search revealed 82 articles, of which 8 were eligible for the study. Five studies were prospective and three retrospective. The majority of authors analysed BRAF mutations in FNA samples which were classified by the British or Bethesda system. Of the initial series of studies, a pooled number of 1361 cases were achieved of which 43 were BRAF mutated. Overall, the BRAF mutation rate was 4·6% (95% CI: 1-10·8%), ranging from 0 to 22·9%. When we included only histological series, 978 thyroid nodules were found. Of these, 245 were cancers. A very low rate of lesions with indeterminate cytology are BRAF mutated. Thus, the role of this biomarker to detect or exclude cancers in patients with such FNA reports is marginal and should be reconsidered in guidelines.

Mutations of K-ras and v-raf murine sarcoma viral oncogene homolog B1 gene in colorectal cancer and their clinical significance

Objective To investigate mutations of K- ras and v- raf murine sarcoma viral oncogene homolog B1(BRAF) genes in colorectal cancer and their clinical significance. Methods 412 cases of colorectal cancer tissue specimens were selected.Real- time quantitative polymerase chain reaction(Real- time PCR) was used to study the characteristics of K- ras and BRAF gene mutation sites and their relationship with clinicopathologic parameters. Results In 412 cases, the mutation rate of K- ras gene was 37.9%.The K- ras mutation rate in rectal cancer(45.2%) was higher than in colon cancer(28.8%, P< 0.05). The rate of single locus mutation was 35.4%, while the rate of double locus mutation was 2.2% and the rate of triple locus mutation was 0.2%.The K- ras mutation was most commonly located in codons 12 and 13,in which the rate of codon 12 was 32.0%.The mutation patterns of codon 12 included G12D(15.0%), G12V(9.5%), G12C(3.9%), G12S (2.9%), G12A(2.4%) and G12R(0.7%). The mutation pattern of thre codon 13 was G13D (6.1%).G→A was the most common mutation pattern.The K- ras gene mutation rate ofⅠ+Ⅱstage(30.4%) was lower than that ofⅢ+Ⅳstage(45.2%), with statistically significant difference(P< 0.05). Further analysis showed the mutation rate(5.9%)of G12V in TNM stageⅠ+Ⅱwas lower than that in stageⅢ+Ⅳ(13.0%, P< 0.05). The K- ras mutation was irrelevant to gender, age, tumor size, clinical tumor type, histological classification and lymphatic metastasis. The BRAFV600E mutation rate of colorectal cancer was 2.4%, and that of colon cancer(4.9%) was higher than rectal cancer(0.4%), with statistically significant difference(P<0.05). Conclusion In colorectal cancer, single locus mutation is most common in K- ras mutation, in which G12D was the main pattern. The mutation status of the G12V can probably promote the progresssion of colorectal cancer.The K- ras mutation rate in rectal cancer was higher than in colon cancer, while the BRAF mutation rate in colon cancer was higher than in rectal cancer.The mechanisms of K- ras and BRAF mutation in colon and rectal cancers may be different. Key words: K-ras gene; v-raf murine sarcoma viral oncogene homolog B1 gene; Gene mutation; Colorectal caner

Metaanalysis of BRAF mutations and clinicopathologic characteristics in primary melanoma

BRAF mutations occur in some melanomas. We hypothesized that BRAF mutation rates may differ in melanomas found in Asian compared to white populations. We performed a metaanalysis of BRAF mutations and their associations with the clinicopathologic characteristics of primary melanoma (PM), with a subgroup analysis to compare Asian and white patients with PM. The PubMed, EMBASE, and Cochrane databases were searched up to November 2013. The incidence rates and odds ratios (ORs) of BRAF mutations were calculated using a fixed or random effects model. BRAF mutation was associated with younger age (OR= 1.734; P < .001), trunk location (OR= 2.272; P < .001), non-chronically sun damaged skin (OR= 2.833; P < .001), superficial spreading melanoma (OR= 2.081; P < .001), and advanced melanoma stage (OR= 1.551; P= .003). The incidence of BRAF mutations in Asian patients with PM was half that of white patients with PM, but it was linked to the same clinicopathologic characteristics. Only a small number of studies have been conducted on Asian patients with PMs. The BRAF mutation in PM was associated with age, anatomic site based on ultraviolet radiation exposure, histologic subtype, and advanced stage of melanoma. The clinicopathologic associations with BRAF mutations were similar in Asian and white patients with PM.

Association between BRAF V600E mutation and central lymph node metastasis in patients with papillary thyroid carcinoma

To investigate the association of concomitant BRAFV600E mutation with central lymph node metastases in papillary thyroid carcinoma (PTC). The clinicopathological data of 126 PTC patients who underwent surgical treatment within a period of 2 years were retrospectively analyzed. The BRAF V600E gene mutation was detected by quantitative fluorescence PCR. The BRAF mutation rate was 69.0% (87/126). The univariate analysis showed that BRAF mutation status was significantly associated with central lymph node metastasis (P<0.05), while the gender, multiple lesions, tumor size, extra-thyroidal invasion, Hashimoto's thyroiditis and tumor stage were not significantly associated with the BRAF mutation (P>0.05 for all). The multivariate analysis showed that only central lymph node metastasis was significantly correlated with BRAF mutation (P<0.05). When the diameter of tumor was ≤10 mm, BRAF mutation was statistically not significantly correlated to central lymph node metastasis (P>0.05). When the diameter of tumor was >10 mm, the central lymph node metastasis rate was significantly higher in patients with positive BRAF mutation than that in patients with a negative BRAF mutation (P<0.05). The presence of BRAF mutation is an independent predictive factor for central lymph node metastasis. When PTC is with preoperative positive BRAF mutation, the cervical dissection should be routinely performed. The larger the tumor diameter is, the more important is the central lymph node dissection. There should be re-evaluated the necessity of preventative central lymph node dissection when the tumor diameter was ≤5 mm in patients with negative BRAF mutation.

Low Grade Serous Ovarian Carcinoma: from the molecular characterization to the best therapeutic strategy.

Low Grade Serous Ovarian Carcinoma, LGSOC, is certainly a rare disease, accounting for only a small proportion of all ovarian carcinomas, nevertheless in the last decade we have acquired many data about its molecular and clinical features and it has been largely accepted that it has distinct pathogenesis, genetic aberrations and clinical behavior compared to High Grade Serous Ovarian Carcinoma, HGSOC, which is the most common ovarian cancer histotype. A large number of series pointed out the high rate of KRAS and BRAF mutations in LGSOCs and Serous Borderline Tumors, SBLTs, in contrast with their rarity in HGSOC. Such finding, together with the recurrent observation of focus of LGSOC associated with areas of SBLT in the same lesion, led to abandon the traditional histology classification, defining three types of serous carcinomas, in favor of a new dualistic grading system which recognizes only LG and HG carcinomas corresponding to distinct tumorigenesis pathways, the former based on KRAS/BRAF mutations and alteration of the MAP/ERK signaling, the latter characterized by early genetic instability and wild type status of KRAS and BRAF. LGSOC shows favorable overall survival, compared to general ovarian cancer population, but worrying resistance to conventional treatments. MEK inhibitors are emerging as active agents and may well represent an effective therapeutic strategy in the near future.

Mutation Analysis of Melanoma Patients with Leptomeningeal Disease (Lmd) Receiving Intrathecal Interleukin-2 (It-Il-2) at Md Anderson Cancer Center (Mdacc)

ABSTRACT Aim: LMD is a devastating end-stage complication of Malignant Melanoma (MM). It remains one of the most difficult forms of this disease, with a dismal median survival ranging from 8-10 weeks. The incidence of LMD is increasing, secondary to improved systemic treatments and increasing longevity for patients with MM. However, treatment for LMD remains mostly supportive with or without palliative craniospinal irradiation. At MDACC, we have been treating MM LMD patients with IT IL-2 for over 20 years. Little has been published regarding the mutation status of this special population. Here we present the molecular aberrations in BRAF, NRAS and CKIT in a cohort of MM LMD patients at MDACC. Methods: Between 1994 and 2014, we followed consecutive MM LMD patients receiving IT IL-2 at MDACC. A total of 43 patients were treated and their data collected. Mutation analysis became a routine part of our practice in 2010 where tumor tissue or cerebrospinal fluid cytology was available. Results: Of the 43 patients who received IT IL-2, 30 had evaluable molecular results. The most common mutation in MM LMD patients receiving IT IL-2 was BRAF, present in 63% (n = 19), followed by NRAS, which was present in 27% (n = 8), with no patients carrying the CKIT mutation. Three patients (10%) were wild-type for BRAF, NRAS and CKIT genes. We compared this high BRAF and NRAS mutation rate (90%) to that seen in the general melanoma population (65%). Using an exact two-sided binomial test, this higher frequency in MM LMD patients undergoing treatment with IT IL-2 was statistically significant with a p-value of 0.0038. Conclusions: In our small series of patients with MM LMD undergoing treatment with IT IL-2, a high frequency of BRAF and NRAS mutations was seen (90%). This is statistically significant when compared to the general MM population, where BRAF and NRAS rates approach 65% (p = 0.0038). This difference may be due to patient selection, or it may signify a predisposition for patients with certain genetic aberrations to develop fatal LMD. More patients are needed to corroborate this finding. Detailed demographics and updates will be presented at the meeting. Disclosure: All authors have declared no conflicts of interest.