PURPOSE GI stromal tumor (GIST) is the most common sarcoma of the GI tract. Management of patients with GIST is determined by KIT, PDGFRA, or other genomic alterations. Tissue-based next-generation sequencing (NGS) analysis is the standard approach for diagnosis, prognosis, and treatment selection. However, circulating tumor DNA (ctDNA)–based NGS is a novel and noninvasive alternative. METHODS ctDNA sequencing results were evaluated in blood samples from 243 de-identified patients within the Guardant360 database. Under an approved institutional review board protocol, a retrospective analysis was performed on 45 single-institution patients. RESULTS Of 243 patients, 114 (47%) were women, and the median age was 59 years (range, 17-90 years). Patients with no alterations and variations of uncertain significance were excluded. Of the 162 patients with known pathogenic mutations, KIT was the most common (56%), followed by NF (7%), PDGFRA (6%), PI3KCA (6%), KRAS (5%), and others (6%). Most tumors harbored an actionable KIT or PDGFRA mutation. Our institutional cohort (n = 45) had 16 (35%) KIT exon 11 mutations, 3 (6%) KIT exon 9 mutations, and 1 (2%) PDGFRA mutation detected on ctDNA. Resistance mutations were observed in KIT exon 17 (8 patients), exon 13 (3 patients), and in both (3 patients). Our comparison of ctDNA with tissue NGS revealed a positive predictive value (PPV) of 100%. Failure of concordance was observed in patients with localized or low disease burden. From the time of ctDNA testing, the median overall survival was not reached, whereas the median progression-free survival was 7 months. CONCLUSION ctDNA provides a rapid, noninvasive analysis of current mutations with a high PPV for patients with metastatic GIST. ctDNA-based testing may help to define the optimal choice of therapy on the basis of resistance mutations and should be studied prospectively.

We performed a retrospective analysis of angiosarcoma (AS) genomic biomarkers and their associations with the site of origin in a cohort of 143 cases. Primary sites were head and neck (31%), breast (22%), extremity (11%), viscera (20%), skin at other locations (8%), and unknown (9%). All cases had Next Generation Sequencing (NGS) data with a 592 gene panel, and 53 cases had Whole Exome Sequencing (WES) data, which we used to study the microenvironment phenotype. The immunotherapy (IO) response biomarkers Tumor Mutation Burden (TMB), Microsatellite Instability (MSI), and PD-L1 status were the most frequently encountered alteration, present in 36.4% of the cohort and 65% of head and neck AS (H/N-AS) (p < 0.0001). In H/N-AS, TMB-High was seen in 63.4% of cases (p < 0.0001) and PDL-1 positivity in 33% of cases. The most common genetic alterations were TP53 (29%), MYC amplification (23%), ARID1A (17%), POT1 (16%), and ATRX (13%). H/N-AS cases had predominantly mutations in TP53 (50.0%, p = 0.0004), POT1 (40.5%, p < 0.0001), and ARID1A (33.3%, p = 0.5875). In breast AS, leading alterations were MYC amplification (63.3%, p < 0.0001), HRAS (16.1%, p = 0.0377), and PIK3CA (16.1%, p = 0.2352). At other sites, conclusions are difficult to generate due to the small number of cases. A microenvironment with a high immune signature, previously associated with IO response, was evenly distributed in 13% of the cases at different primary sites. Our findings can facilitate the design and optimization of therapeutic strategies for AS.

Despite the benefits of first and second generation anaplastic lymphoma kinase (ALK) inhibitors in the management of ALK-rearranged advanced non-small-cell lung cancer (NSCLC), the development of acquired resistance poses an ongoing dilemma. Brigatinib has demonstrated a wider spectrum of preclinical activity against crizotinib-resistant ALK mutant advanced NSCLC. The current review narrates a brief history of tyrosine kinases, the development and clinical background of brigatinib (including its pharmacology and molecular structure) and its use in ALK-positive NSCLC.

Background. In Brazil, cancer is the second most common cause of death. Most patients in resource-limited countries are diagnosed in advanced stages. Current guidelines advocate for EGFR mutation testing in all patients with metastatic adenocarcinoma. Tyrosine kinase inhibitors are recommended in patients with advanced or metastatic disease harboring sensitizing mutations. In Brazil, there are limited data regarding the frequency of EGFR testing and the changes in patterns of testing overtime. Materials and Methods. This was an observational, retrospective study. We obtained deidentified data from a commercial database, which included 11,684 patients with non-small cell lung cancer treated between 2011 and 2016 in both public and private settings. We analyzed the frequency of EGFR mutation testing over time. We also directly studied 3,664 tumor samples, which were analyzed between 2011 and 2013. These samples were tested for EGFR mutations through an access program to tyrosine kinase inhibitors in Brazil.Results. Overall, 38% of patients were tested for EGFR mutations; 76% of them were seen in the private sector, and 24% were seen in the public center. The frequency of testing for EGFR mutations increased significantly over time: 13% (287/2,228 patients) in 2011, 34% (738/2,142) in 2012, 39% (822/2,092) in 2013, 44% (866/1,972) in 2014, 53% (1,165/2,184) in 2015, and 42% (1,359/3,226) in 2016. EGFR mutations were detected in 25.5% of analyzed samples (857/3,364). Deletions in Exon 19 were the most frequent mutations, detected in 54% of patients (463/857). Conclusion. Our findings suggest that the frequency of EGFR mutation in this cohort was lower than that found in Asia but higher than in North American and Western European populations. The most commonly found mutations were in Exon 19 and Exon 21. Our study shows that fewer than half of patients are being tested and that the disparity is greater in the public sector. The Oncologist 2019;24:e137-e141 Implications for Practice: These data not only indicate the shortage of testing but also show that the rates of positivity in those tested seem to be higher than in other cohorts for which data have been published. This study further supports the idea that awareness and access to testing should be improved in order to improve survival rates in lung cancer in Brazil.