BRAF K601E Mutation Research Articles

The Prevalence and Prognostic Implications of BRAF K601E Mutations in Thyroid Neoplasms: A Systematic Review and Meta-Analysis.

Activating mutations in the BRAF oncogene occur in 45% of papillary thyroid carcinomas (PTCs). Though less studied, K601E may identify a clinically distinct subset of thyroid neoplasms. A bioinformatics assessment was conducted using the COSMIC database and in silico data analysis. A systematic search was conducted through August 2024 to identify studies reporting BRAF mutation in thyroid neoplasms. Pooled prevalence, histopathological subtype distribution, extrathyroidal extension, lymph node metastasis, recurrence, and survival were extracted/analyzed from 32 studies (13 191 patients). In the COSMIC database, BRAF K601E was found in various tissue types but mainly in the thyroid. In silico data analysis revealed a structural and functional basis for differences between K601E and V600E. Upon systematic review, the BRAF K601E mutation was identified in 2.8% of PTCs compared to 22% with V600E. The stratified analysis revealed geographical differences, with higher rates in Italy (5.23%) and the United States of America (3.31%). The K601E mutant was enriched for follicular-patterned variants like NIFTP (11.2% of cases). Meta-analysis demonstrated significantly reduced extrathyroidal extension for K601E versus V600E mutants (RR = 0.22, 95% CI = 0.10-0.50, p = 0.0003). K601E-mutated neoplasms could be a unique clinicopathological entity associated with low-risk histology and reduced extrathyroidal extension, consistent with a more indolent course than V600E mutants. Although detecting K601E may potentially guide conservative management, further prospective studies are needed.

Patients with radioiodine-refractory differentiated thyroid cancer (RAI-R DTC) with BRAF V600E and/or K601E mutation status: A real-world view of effectiveness of lenvatinib monotherapy.

6098 Background: Lenvatinib was approved for the treatment of patients RAI-R DTC in the United States (US) in 2015, and the treatment landscape has evolved with agents targeting specific driver mutations. We assessed real-world clinical effectiveness of first line therapy with lenvatinib in patients with BRAF-mutated tumors, wild-type (WT) tumors, and patients who have not been tested for BRAF mutations (BRAF untested tumors). Methods: A retrospective chart review of RAI-R DTC patients in the US who initiated first-line lenvatinib monotherapy between February 13, 2015, and September 30, 2020. Data, including a boosted cohort of patients with BRAF-mutated tumors collected in late 2023, were abstracted from patients’ electronic health records and were de-identified. Descriptive analyses were conducted in patient cohorts with BRAF V600E and/or K601E mutated tumors, wild-type (WT) tumors, and BRAF untested tumors. Best response in first-line therapy was captured, real-world progression-free survival (rwPFS) and real-world overall survival (rwOS) were assessed using Kaplan-Meier methods. Results: Of the 361 patients reviewed, 185 had records showing BRAF mutational status testing. 89 had BRAF V600E and/or K601E mutated tumors, 96 had WT tumors. 176 patients did not have BRAF mutational assessment. Of all subjects, 73.7% were White/Caucasian, 15.2% were African American, and 16.8% were Hispanic/Latino; 27.1% had ECOG performance status ≥2. The median follow-up times for each cohort were 30.0, 18.7 and 18.0 months, showing the longer follow up period for the BRAF-mutated cohort boost. Kaplan-Meier estimation for lenvatinib treatment discontinuation for the three cohorts at 24-months were as shown in the table below. Provider-reported overall response rate (complete or partial response) was 76.4%, 75.0% and 69.3% respectively. The estimated 24-month rwPFS rates (95% CI) were 74.1% (62.2%-82.8%), 61.7% (49.6%-71.8%), and 69.8% (60.9%-77.0%) respectively. Median rwOS was not reached for patients with BRAF-mutated and WT tumors, median OS was 54.2 months for BRAF untested tumors. Estimated rwOS rates at 12- and 48-months were 93.2% (85.4%-96.9%) and 83.9% (73.3%-90.3%) in BRAF-mutated patients, 90.6% (82.8%-95.0%) and 68.5% (53.4%-79.6%) in WT patients, and 90.2% (84.7%-93.8%) and 72.5% (61.6%-80.7%) in BRAF untested patients respectively. Conclusions: In this US real-world experience, the effectiveness of lenvatinib is consistent across a diverse cohort of RAI-R DTC patients with BRAF-mutated, WT, and BRAF untested tumors. This has implications for the first-line use of lenvatinib in BRAF mutated patients. [Table: see text]

The BRAF K601E mutation in thyroid tumors: One alteration with a dual clinical significance

The BRAF K601E mutation in thyroid tumors: One alteration with a dual clinical significance

Indeterminate Thyroid Nodules: From Cytology to Molecular Testing.

Thyroid cancer is the most common malignancy of the endocrine system. Fine-needle aspiration (FNA) biopsy of thyroid nodules has become the gold standard procedure, in terms of cost and efficacy, for guiding clinicians towards appropriate patients' management. One challenge for cytopathologists is to accurately classify cytological specimens as benign or malignant based on cytomorphological features. In fact, with a frequency ranging from 10% to 30%, nodules are diagnosed as indeterminate. In recent years, the mutational landscape of thyroid tumors has been extensively described, and two molecular profiles have been identified: RAS-like (NRAS, HRAS, and KRAS mutations; EIF1AX mutations; BRAF K601E mutation; and PPARG and THADA fusions) and BRAFV600E-like (including BRAFV600E mutation and RET and BRAF fusions). The purpose of this review is to discuss the latest molecular findings in the context of indeterminate thyroid nodules, highlighting the role of molecular tests in patients' management.

Cobimetinib Plus Vemurafenib in Patients With Solid Tumors With BRAF Mutations: Results From the Targeted Agent and Profiling Utilization Registry Study.

The Targeted Agent and Profiling Utilization Registry Study is a phase II basket study evaluating antitumor activity of commercially available targeted agents in patients with advanced cancers with genomic alterations known to be drug targets. The results in a cohort of patients with solid tumors with BRAF mutations treated with cobimetinib plus vemurafenib are reported. Eligible patients had measurable disease (RECIST v.1.1), Eastern Cooperative Oncology Group performance status 0-2, adequate organ function, and no standard treatment options. The primary end point was disease control (DC), defined as complete response (CR) or partial response (PR) or stable disease of at least 16-weeks duration (SD16+). Low-accruing histology-specific cohorts with BRAF mutations treated with cobimetinib plus vemurafenib were collapsed into a single histology-pooled cohort for this analysis. The results were evaluated on the basis of a one-sided exact binomial test with a null DC rate of 15% versus 35% (power, .82; α, .10). The secondary end points were objective response (OR), progression-free survival, overall survival, duration of response, duration of stable disease, and safety. Thirty-one patients with solid tumors with BRAF mutations were enrolled. Twenty-eight patients were evaluable for efficacy. Patients had tumors with BRAF V600E (n = 26), K601E (n = 2), or other (n = 3) mutations. Two patients with CR (breast and ovarian cancers; V600E), 14 with PR (13 V600E, one N581I), and three with SD16+ (two V600E, one T599_V600insT) were observed with a DC rate of 68% (P < .0001; one-sided 90% CI, 54 to 100) and an OR rate of 57% (95% CI, 37 to 76). Nineteen patients experienced ≥one drug-related grade 3-5 adverse event or serious adverse event including one death attributed to treatment-related kidney injury. Cobimetinib plus vemurafenib showed antitumor activity in patients with advanced solid tumors with BRAF V600E mutations; additional study is warranted to confirm the antitumor activity in tumors with non-V600E BRAF mutations.

Abstract 5348: Targeting MEK, alone and in combination with BRAF, in metastatic BRAFK601E-mutated melanoma

Abstract Mitogen-activated protein kinase/ERK signaling pathway has been one of the major mechanisms underlying melanoma haboring BRAF mutation. Of these, K601E mutation belongs to a rare mutation sub-type, comprising only 3% of the BRAF mutations in melanoma. Although patients with BRAF V600E/K mutation respond to MEK inhibitor, whether it also applies to those with BRAF K601E mutation remains elusive. Here, we examined the effects of MEK and BRAF/MEK inhibition on BRAFK601E-expressing melanoma cells. Melanoma cell line (MeWo) was transfected with doxycycline-inducible vector encoding wild-type or K601E-mutant BRAF. Subsequently, cells or xenograft-bearing mice were treated with trametinib, dabrafenib plus trametinib or sorafenib plus trametinib. Compared with BRAFWT, MTT assay demonstrated that BRAFK601E cells were more sensitive towards drug treatment. The effects of combined treatment were more profound. Tumorigenicity assay showed that trametinib treatment inhibited tumor growth of BRAFK601E xenografts. Our preliminary results demonstrated the therapeutic values of MEK and BRAF/MEK inhibitors against BRAFK601E-mutated melanoma. As previous studies report the superior therapeutic effects of BRAF/MEK inhibitors over MEK inhibitor alone, phenotype characterization of the cells, as well as underlying mechanisms behind such response, worth further investigation. Citation Format: Sze Man Chan, Sin Ting Chow, Sai Fung Yeung, Kwok Wing Stephen Tsui. Targeting MEK, alone and in combination with BRAF, in metastatic BRAFK601E-mutated melanoma. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5348.

Cobimetinib Plus Vemurafenib in Patients With Colorectal Cancer With BRAF Mutations: Results From the Targeted Agent and Profiling Utilization Registry (TAPUR) Study.

TAPUR is a phase II basket trial evaluating the antitumor activity of commercially available targeted agents in patients with advanced cancer and genomic alterations known to be drug targets. The results of a cohort of patients with colorectal cancer (CRC) with BRAF mutations treated with cobimetinib (C) plus vemurafenib (V) are reported. Eligible patients had advanced CRC, no standard treatment options, measurable disease (RECIST), Eastern Cooperative Oncology Group performance status 0-2, adequate organ function, tumors with BRAF V600E/D/K/R mutations, and no MAP2K1/2, MEK1/2, or NRAS mutations. C was taken 60 mg orally once daily for 21 days followed by seven days off, and V was taken 960 mg orally twice daily. Simon's two-stage design was used with a primary study end point of objective response or stable disease of at least 16 weeks duration. Secondary end points were progression-free survival, overall survival, and safety. Thirty patients were enrolled from August 2016 to August 2018; all had CRC with a BRAF V600E mutation except one patient with a BRAF K601E mutation. Three patients were not evaluable for efficacy. Eight patients with partial responses and six patients with stable disease of at least 16 weeks duration were observed for disease control and objective response rates of 52% (95% CI, 35 to 65) and 30% (95% CI, 14 to 50), respectively. The null hypothesis of 15% disease control rate was rejected (P < .0001). Thirteen patients had at least one grade 3 adverse event or serious adverse event at least possibly related to C + V: anemia, decreased lymphocytes, dyspnea, diarrhea, elevated liver enzymes, fatigue, hypercalcemia, hypophosphatemia, rash, photosensitivity, and upper gastrointestinal hemorrhage. The combination of C + V has antitumor activity in heavily pretreated patients with CRC with BRAF mutations.

Clinicopathologic Characteristics and Postsurgical Follow-Up of Noninvasive Follicular Thyroid Neoplasm with Papillary-Like Nuclear Features in the Postnomenclature Revision Era.

Background: Noninvasive encapsulated follicular variant papillary thyroid carcinoma (EFVPTC) was reclassified as "noninvasive follicular thyroid neoplasm with papillary-like nuclear features" (NIFTP) in 2016. Most existing studies that examined outcomes included patients managed as EFVPTC and only retrospectively reclassified as NIFTP. This is the first study to evaluate the clinicopathologic, molecular, and surveillance characteristics of patients diagnosed with NIFTP at the time of surgery and managed based on this diagnosis. Methods: We performed a retrospective cohort study of consecutive cases diagnosed as NIFTP from June 2016 to October 2021 identified from electronic medical records at a large tertiary care institution. Patients with coexisting low-risk thyroid cancers ≥1.0 cm in size or any size aggressive histology were excluded, and review of demographic, clinical, imaging, cytologic, and molecular genetic data was performed. Initial care was delivered according to existing clinical guidelines, with a consensus institutional plan for five-year follow-up after surgery. Results: Among 79 patients with 84 nodules diagnosed as NIFTP after surgery, 83.5% (66/79) were women and the mean age was 51 years (range, 21-84). Mean NIFTP size was 2.4 cm (range 0.15-8.0). On ultrasound, the majority of nodules were categorized as thyroid imaging, reporting and data system TI-RADS 3 (55.3%, 42/76), and TI-RADS 4 (36.8%, 28/76). On cytology, they were typically diagnosed as Bethesda III (69.1%, 47/68) or Bethesda IV (23.5%, 16/68). Molecular testing was performed on 62 nodules, and molecular alterations were found in 93.5% (58/62). The most common alterations identified in NIFTP were RAS mutation (75.4%, 43/57), THADA fusion (12.3%, 7/57), and BRAFK601E mutation (7.0%, 4/57). Fifty-two (65.8%) patients underwent lobectomy and 27 (34.2%) total thyroidectomy, and no patient received completion thyroidectomy. Twenty-one patients (26.5%) had coexisting papillary or follicular microcarcinoma. None of the patients received radioiodine ablation. On a mean follow-up of 28.5 months (range, 6-69 months), no structural or biochemical recurrences were observed. Conclusions: In this large cohort of patients with NIFTP diagnosed at the time of surgery and managed typically by lobectomy with no radioiodine ablation, no evidence of tumor recurrence was identified on a limited follow-up. This finding supports indolent clinical course of NIFTP.

Molecular alterations in Hürthle cell neoplasms of thyroid: A fine needle aspiration cytology study with cytology-histology correlation.

Hürthle cell features are frequently observed on the fine-needle aspiration (FNA) cytology of thyroid nodules and often pose a diagnostic challenge because of a significant overlap between cytomorphologic features seen in benign and malignant lesions. Molecular alterations (MAs) associated with these lesions are not well described. The objective of the current study was to evaluate the molecular profile of Hürthle cell lesions classified as Hürthle cell neoplasm (HCN) on cytologic evaluation. The authors retrospectively reviewed their electronic database for cytologic diagnoses of HCN from January 1, 2017 to March 31, 2020. In total, 279 cases from 275 patients who had a diagnosis of HCN were included in the study. Molecular testing results were available in 85 cases (51 with MAs and 34 without MAs) and, of those, 42 had histologic follow-up available. Eight of 10 malignant cases had MAs, whereas the remaining 2 cases were negative for MAs. The most frequently encountered predominant genetic alterations or classifier findings were chromosome copy number alterations (n = 15), followed by NRAS (n = 8), KRAS (n = 7), suspicious (n = 6), EIF1AX (n = 4), TSHR (n = 3), gene overexpression (n = 3), positive microRNA classifier (n = 2), and 1 each of BRAF K601E, TERT, and HRAS mutations. One hundred thirty-seven cases had histologic follow-up available; of those, 28 were classified as malignant, and 109 were classified as benign (neoplastic and nonneoplastic). The overall risk of malignancy associated with HCN was 20%, and the risk of HCN with MAs was 25%. The cytologic diagnosis of HCN includes various MAs without any obvious trend, and most malignant cases (80%) have some type of MA.

Preoperative Role of RAS or BRAF K601E in the Guidance of Surgery for Indeterminate Thyroid Nodules.

RAS and K601E BRAF mutations are not a reliable indicator of malignancy in fine-needle aspirations (FNA) of thyroid indeterminate cytologic nodules. We aimed to evaluate the histologic characteristics, the risk of malignancy associated with such mutations in FNA and their potential interest for preoperative clinical management of nodules. We evaluated 69 indeterminate thyroid nodules with RAS or K601E BRAF mutations with available histopathologic follow-up. All FNA specimens were indeterminate according to the thyroid Bethesda system. Diagnosis of malignant, benign or indolent neoplasms was classified according to 2017 WHO classification. Carcinoma, NIFTP (noninvasive follicular thyroid neoplasm with papillary-like features) and WDTUMP (well-differentiated tumor of uncertain malignant potential) were considered "surgical," as they require surgical excision. Adenoma was considered "non-surgical." The risk of malignancy and the risk of "surgical disease" were evaluated. Pathologic evaluation of the 69 mutated nodules demonstrated benign, indolent and malignant histology in 17 cases (25%), 21 cases (30%) and 31 cases (45%), respectively. The risk of malignancy was 45%, and the risk of surgical disease was 75%. The majority of carcinomas were a follicular variant of papillary thyroid carcinoma. On follow-up, there have been no recurrences to date. Preoperative RAS or BRAF K601E mutations detection in cytologic indeterminate thyroid nodules carries a high risk of surgical disease and may benefit from surgical management. Most surgical lesions harboring those mutations are low-risk tumors, which may be in favor of an initial lobectomy.

Eradication of BRAF K601E Mutation in Metastatic Castrate-resistant Prostate Cancer Treated With Cabazitaxel and Carboplatin: A Case Report

Eradication of BRAF K601E Mutation in Metastatic Castrate-resistant Prostate Cancer Treated With Cabazitaxel and Carboplatin: A Case Report

Patient-Derived Cells to Guide Targeted Therapy for Advanced Lung Adenocarcinoma

Adequate preclinical model and model establishment procedure are required to accelerate translational research in lung cancer. We streamlined a protocol for establishing patient-derived cells (PDC) and identified effective targeted therapies and novel resistance mechanisms using PDCs. We generated 23 PDCs from 96 malignant effusions of 77 patients with advanced lung adenocarcinoma. Clinical and experimental factors were reviewed to identify determinants for PDC establishment. PDCs were characterized by driver mutations and in vitro sensitivity to targeted therapies. Seven PDCs were analyzed by whole-exome sequencing. PDCs were established at a success rate of 24.0%. Utilizing cytological diagnosis and tumor colony formation can improve the success rate upto 48.8%. In vitro response to a tyrosine kinase inhibitor (TKI) in PDC reflected patient treatment response and contributed to identifying effective therapies. Combination of dabrafenib and trametinib was potent against a rare BRAF K601E mutation. Afatinib was the most potent EGFR-TKI against uncommon EGFR mutations including L861Q, G719C/S768I, and D770_N771insG. Aurora kinase A (AURKA) was identified as a novel resistance mechanism to olmutinib, a mutant-selective, third-generation EGFR-TKI, and inhibition of AURKA overcame the resistance. We presented an efficient protocol for establishing PDCs. PDCs empowered precision medicine with promising translational values.

Precision medicine: BRAF mutations in thyroid cancer

Mutations in BRAF are commonly seen in thyroid carcinoma and can have therapeutic and prognostic implications. The BRAF V600E mutation is seen in approximately 40% of cases of papillary thyroid carcinoma (PTC), and is associated with aggressive clinicopathological features, higher recurrence rate, and disease related mortality. Significant advances have occurred in the development of new therapeutic targets of the MAP kinase pathway, which is activated in the setting of BRAF mutations, including BRAF and mitogen extracellular kinase (MEK) inhibitors. BRAF alterations other than V600E are less common in PTC, and their clinical significance remains to be established. Here we present a case of a male with poorly differentiated thyroid carcinoma, with papillary and follicular features, who was noted to have a BRAF K601E mutation. The patient was subsequently treated with a BRAF inhibitor, dabrafenib, and MEK inhibitor, trametinib.

Abstract 3999: Advanced lung adenocarcinoma cell bank (ALACB) : A comprehensive preclinical platform

Abstract Purpose: Patients with advanced lung adenocarcinoma often lack large clinical specimens required for molecular testing which limits next therapeutic options. Patient-derived cells (PDC) from malignant effusions can predict patient drug responses and provide a valuable tool for studying drug resistance mechanisms. In this study, we created an Advanced Lung Adenocarcinoma Cell Bank (ALACB) consisting of 28 unique PDCs established from patients who progressed on various tyrosine kinase inhibitor TKIs including 3rd generation EGFR TKI osimertinib. Experimental design: Patient malignant effusion samples were tested for malignancy, processed, observed by light microscopy, and cultured with appropriate media and supplements. The criteria for established PDCs include the following: sharing the same driver mutation as the patient; free of stromal fibroblasts confirmed by FACS staining; recapitulating patient’s drug response; and can be cryopreserved and re-grown. Established PDCs were further authenticated by STR profiling and microplasma testing to maintain cell quality. We were able to perform various in vitro assays and next generation sequencing for detailed analysis of individual PDC. Results: We were able to successfully establish 28 PDCs incorporating unique patient characteristics. Among the total 146 samples, we observed a success rate of 30% only accounting 95 malignancy positive samples. Established PDCs consists of 20 EGFR mutation positive cell lines, 3 with ALK rearrangements, 6 with ROS1 rearrangements, 1 with BRAF K601E mutation and 1 with KRAS G12D mutation. Seven PDCs were established from patients who progressed on osimertinib, two from olmutinib (HM61713), and others from 1st and 2nd generation EGFR TKI such as gefitininb and erlotinib. We were able to newly generate 3 PDCs harboring a T790M mutation with an activating EGFR mutation. Moreover, we are one of the few labs to successfully establish an EGFR del19/T790M/C797S triple mutant PDC showing resistance to osimertinib treatment in vitro. Other established PDCs harbored rare EGFR mutations including exon 20 insertion, L861Q and G719X/S768I. PDC with EGFR G719X/S768I compound mutation showed high sensitivity to afatinib but was resistant to gefitininb and osimertinib treatment. Three ALK-positive PDCs were derived from crizotinib-resistant, alectinib-resistant and ceritinib-resistant tumors. Furthermore, of 6 ROS1 fusion positive PDCs, 3 were derived from TKI-naïve tumors, and 3 from crizotinib-resistant tumors. Conclusions: Successfully established PDCs reflecting patient genomic profiles and drug response is a valuable resource for biological assays, generating in vitro drug-resistant models, and evaluating novel drugs and therapeutic targets. Further advances in drug development combined with a library of cell bank will facilitate lung cancer translational research. Citation Format: Hyeong-Seok Joo, Dong Hwi Kim, Seok-Young Kim, Ji-Yeon Lee, Mi-Ran Yun, Han-Na Kang, Byoung Chul Cho, Hye Ryun Kim. Advanced lung adenocarcinoma cell bank (ALACB) : A comprehensive preclinical platform [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3999.

Clinical utility of EZH1 mutations in the diagnosis of follicular-patterned thyroid tumors

Follicular-patterned tumors of the thyroid gland are characterized by a predominantly follicular growth pattern. They frequently harbor RAS mutations, not BRAF mutations. Technological advances in molecular testing have discovered novel RAS-type mutations. However, clinical significance of these mutations remains unknown. We investigated the prevalence and clinical impact of mutations of BRAF, NRAS, HRAS, KRAS, EZH1, EIF1AX, and TERT genes by Sanger sequencing in a series of 201 follicular-patterned thyroid tumors including follicular adenoma (n = 40), Hürthle cell adenoma (n = 54), noninvasive follicular thyroid neoplasms with papillary-like nuclear features (n = 50), follicular thyroid carcinoma (n = 40), Hürthle cell carcinoma (n = 10), and poorly differentiated thyroid carcinoma arising in a well-differentiated follicular neoplasm (n = 7), and 120 classic papillary carcinoma. Two hotspots of EZH1 mutations were only found in RAS-negative follicular-patterned tumors. EZH1 mutations were detected in 3% of follicular adenoma and in 20% of Hürthle cell adenoma, and one minimally invasive Hürthle cell carcinoma. Thyroid tumors with EZH1 mutations reported in the literature were benign in most cases. Otherwise, they were minimally invasive or noninvasive cancer. EIF1AX mutation was found in one follicular adenoma. We confirmed the presence of RAS mutations and BRAF K601E mutation in benign, borderline, and malignant follicular-patterned tumors. No BRAF V600E was found in all follicular-patterned tumors. This study also confirmed the occurrence of TERT promoter mutations in high-risk thyroid cancers. These genetic markers can be used for the diagnostic purpose and risk stratification of thyroid nodules.

Cell-free DNA (cfDNA) analysis and evaluation of BRAF amplifications and mutations in metastatic castration-resistant prostate cancer.

255 Background: Cell-free DNA (cfDNA) is an accessible method for characterizing tumoral alterations. We report cfDNA screenings of prostate cancer pts positive for BRAF amplifications/mutations in pts with metastatic CRPC. Methods: Guardant360 testing (Guardant Health, Inc.) assesses cell-free DNA analysis using sequencing to identify genomic alterations in 73 cancer-related genes in circulation. A total of 133 metastatic castrate resistant prostate cancer (mCRPC) pts in various stages of therapy had Guardant cfDNA analyses. Treatment histories prior to testing and concurrent cfDNA alterations were analyzed. Results: BRAF amplifications were detected in 32 (24%) mCRPC pts; 5 pts had concurrent BRAF mutations. Of the mutations detected, only one (K601E, n = 2) was a known activating mutation while all others were variants of unknown significance (VUS). One K601E mutation pt had no other cfDNA alterations. Additionally, 4 pts without BRAF amplification had VUS BRAF mutations. BRAF amplification pts had ≥ 2 concurrent gene amplifications/alterations with the median being 8. The most common recurrent amplifications/alterations were AR (75%), p53 (59%), CDK6 (53%), MET (50%), and MYC (50%). Abiraterone (Abi) and/or Enzalutamide (Enza) resistance was associated with BRAF amplification (p = 0.0042). Non-Abi/Enza resistance pts were less likely to have BRAF amplification. The 2 pts with BRAF K601E mutation were treated with targeted protocol therapy without success however one K601E pts was subsequently treated with cabazitaxel+carboplatin which produced a positive clinical response and a 99.79% reduction in PSA. Conclusions: Pts resistant to Abi/Enza have an increased risk of developing BRAF amplifications. BRAF amplifications arise in the context of multiple additional detectable cfDNA alterations. Identification of actionable mutations, such as BRAF K601E, illustrates the potential for cfDNA testing to direct pt treatment. As cfDNA profiling continues to expand, the ability translate alterations into clinically actionable strategies is critical.

BRAF and RAS Mutational Status in Noninvasive Follicular Thyroid Neoplasm with Papillary-Like Nuclear Features and Invasive Subtype of Encapsulated Follicular Variant of Papillary Thyroid Carcinoma in Korea

Noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) is an indolent thyroid tumor previously known as noninvasive subtype of encapsulated follicular variant of papillary thyroid carcinoma (EFVPTC). The absence of BRAFV600E mutations has been considered characteristic of NIFTPs. However, a recent study from Korea found that 28.6% of NIFTPs harbored a BRAF mutation. This study evaluated BRAF and RAS mutations in NIFTPs and invasive subtype of EFVPTCs. This study enrolled 32 patients with NIFTP and 48 with invasive EFVPTC. BRAF, NRAS, HRAS, and KRAS mutations were evaluated by direct sequencing using DNA from fresh-frozen tissues and formalin-fixed, paraffin-embedded tissue samples. The primary tumor size of NIFTP was smaller than that of invasive EFVPTC (median 2.8 cm vs. 3.2 cm; p = 0.03). Cervical lymph node metastases were found in only four (8%) patients with invasive EFVPTC. There was no BRAF mutation in NIFTPs, whereas invasive EFVPTCs had three (6%) BRAFV600E mutations and one (2%) BRAFK601E mutation. RAS mutations were detected in 15 (47%) NIFTPs and 22 (46%) invasive EFVPTCs. NRAS mutations in codon 61 were the most common mutations in NIFTPs (34%) and invasive EFVPTCs (27%). There was no significant difference in the frequency of RAS mutations between the two groups. There was no BRAF mutation in any of the NIFTPs. RAS mutations, particularly mutations in codon 61 of NRAS, were the most common mutations in both NIFTPs and invasive EFVPTCs. The presence of a RAS mutation is not helpful for preoperative differentiation between NIFTPs and invasive EFVPTCs.

A user's guide to non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP).

The term non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) was recently introduced to replace a subset of follicular variant of papillary thyroid carcinoma (FVPTC). The goal of this change was to promote more conservative management of these tumours and spare patients the psychological burden of a cancer diagnosis. The histological diagnosis of NIFTP is stringent: the tumour needs to demonstrate encapsulation or circumscription, a purely follicular architecture and the presence of nuclear features of papillary thyroid carcinoma, while lacking capsular and vascular invasion, a significant component of solid growth and high-grade features (increased mitotic activity and necrosis). In order to ensure that these inclusion and exclusion criteria are met, the tumour must be sampled extensively, with the entire capsule/periphery submitted in all cases. When sampled by fine-needle aspiration, NIFTP is usually classified within the indeterminate categories of the Bethesda System for Reporting Thyroid Cytopathology. NIFTP is characterized genetically by frequent RAS mutations, although rarely other alterations, such as the BRAF K601E mutation and gene rearrangements in PPARG or THADA, may occur. In this review, we will examine the history of FVPTC and the findings and factors that culminated in the introduction of the NIFTP terminology. A discussion will follow with the histological, cytological and molecular characteristics of NIFTP. We will conclude by considering the potential impact of the introduction of the NIFTP terminology.

Frequency and Significance of Ras, Tert Promoter, and Braf Mutations in Cytologically Indeterminate Thyroid Nodules: A Monocentric Case Series at a Tertiary-Level Endocrinology Unit.

The management of thyroid nodules of indeterminate cytology is controversial. Our study aimed to establish the frequency and significance of H-,K-,N-RAS, TERT promoter, and BRAF gene mutations in thyroid nodes of indeterminate cytology and to assess their potential usefulness in clinical practice. H-,K-,N-RAS, TERT promoter and BRAF gene mutations were examined in a series of 199 consecutive nodes of indeterminate cytology referred for surgical excision. 69/199 (35%) were malignant on histopathological review. RAS mutations were detected in 36/199 (18%), and 19/36 cases (53%) were malignant on histological diagnosis. TERT promoter mutations were detected in 7/199 (4%) nodules, which were all malignant lesions. BRAF mutations were detected in 15/199 (8%), and a BRAF K601E mutation was identified in 2 follicular adenomas and 1 noninvasive follicular thyroid neoplasm with papillary-like nuclear features. Altogether, this panel was able to identify 48% of the malignant lesions, achieving a specificity, positive predictive value, and negative predictive value for malignancy of 85, 62, and 75%, respectively. The residual malignancy risk in mutation-negative nodes is 25%. These nodes still need to be resected, but mutation analysis could help to orient the appropriate surgical strategy.

Metastatic BRAF K601E-mutated melanoma reaches complete response to MEK inhibitor trametinib administered for over 36\xa0months

BackgroundThe BRAF K601E mutation occurs in 5% of patients with melanoma, and is the third most common type of BRAF mutation. However, treatment with BRAF and mitogen-activated extracellular signal-regulated kinase (MEK) inhibitors is only approved in patients with BRAF V600-positive melanoma, and patients with K601E-mutated melanoma do not have access to such drugs.Case presentationA female patient was diagnosed with high tumor burden metastatic melanoma harboring the BRAF K601E mutation. After chemotherapy failure, she underwent compassionate treatment with trametinib. Trametinib showed good activity and efficacy, with 48% shrinkage of a metastatic lymphadenopathy after 4 months’ treatment. However, the patient reported treatment-related skin toxicity that required dosage reduction and a personalized intermittent trametinib dosing schedule. After over 36 months from the first trametinib administration, and resection of a metastatic lymphadenopathy, the patient experienced complete response.ConclusionsThis case report shows that trametinib could be a valid therapeutic option in patients with metastatic melanoma harboring the rare BRAF K601E mutation.