RESUMO
BACKGROUND: Extended RAS analysis is mandatory in metastatic colorectal cancer (mCRC) patients. The optimal threshold of RAS mutated subclones to identify patients most likely to benefit from antiepidermal growth factor receptor (EGFR) therapy is controversial. Our aim was to assess the clinical impact of detecting mutations in RAS, BRAF, PIK3CA and EGFRS492R in basal tissue tumour samples by using a highly sensitive next-generation sequencing (NGS) technology in mCRC patients treated with chemotherapy plus anti-EGFR or anti-vascular endothelial growth factor. PATIENTS AND METHODS: Five hundred and eighty-one tumour samples from untreated mCRC patients from 7 clinical studies were collected. Mutational analysis was carried out by standard-of-care (therascreen pyro) with a sensitivity detection of 5% mutant allele fraction (MAF), and compared with NGS technology using 454GS Junior platform (Roche Applied Science, Germany) with a sensitivity of 1%. Molecular results were correlated with clinical outcomes. RESULTS: After quality assessment, 380 samples were evaluable for molecular analysis. Standard-of-care mutational analysis detected RAS, BRAFV600E or PIK3CA mutations in 56.05% of samples compared with 69.21% by NGS (P = 0.00018). NGS identified coexistence of multiple low-frequency mutant alleles in 96 of the 263 mutated cases (36.5%; range 2-7). Response rate (RR), progression-free survival (PFS) and overall survival (OS) were increasingly improved in patients with RAS wild-type, RAS/BRAF wild-type or quadruple (KRAS/NRAS/BRAF/PIK3CA) wild-type tumours treated with anti-EGFR, assessed by standard-of-care. No additional benefit in RR, PFS or OS was observed by increasing the detection threshold to 1% by NGS. An inverse correlation between the MAF of the most prevalent mutation detected by NGS and anti-EGFR response was observed (P = 0.039). EGFRS492Rmutation was not detected in untreated samples. CONCLUSIONS: No improvement in the selection of patients for anti-EGFR therapy was obtained by adjusting the mutation detection threshold in tissue samples from 5% to 1% MAF. Response to anti-EGFR was significantly better in patients with quadruple wild-type tumours.
Assuntos
Neoplasias Colorretais/tratamento farmacológico , GTP Fosfo-Hidrolases/genética , Proteínas de Membrana/genética , Proteínas Proto-Oncogênicas B-raf/genética , Proteínas Proto-Oncogênicas p21(ras)/genética , Adulto , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Cetuximab/administração & dosagem , Classe I de Fosfatidilinositol 3-Quinases/genética , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Análise Mutacional de DNA , Intervalo Livre de Doença , Receptores ErbB/antagonistas & inibidores , Receptores ErbB/genética , Feminino , Alemanha , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Masculino , Pessoa de Meia-Idade , Mutação/genética , Metástase Neoplásica , Inibidores de Proteínas Quinases/administração & dosagem , Resultado do TratamentoAssuntos
Plaquetas/metabolismo , Análise de Sequência de DNA/métodos , Trombocitemia Essencial/diagnóstico , Trombocitemia Essencial/genética , Transcriptoma , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Plaquetas/patologia , Calreticulina/genética , Criança , Estudos de Coortes , Feminino , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Janus Quinase 2/genética , Masculino , Pessoa de Meia-Idade , Técnicas de Diagnóstico Molecular , Polimorfismo de Fragmento de Restrição , Reação em Cadeia da Polimerase em Tempo Real , Receptores de Trombopoetina/genética , Trombocitemia Essencial/patologia , Adulto JovemRESUMO
The biological basis of essential thrombocythemia (ET) patients lacking known mutations is still unknown. MicroRNAs (miRNA) regulate hematopoietic differentiation and are deregulated in several hematopoietic malignancies. However, miRNA expression in ET patients has been poorly explored. We performed miRNA profiling in platelets from 19 ET patients and 10 healthy controls. Hierarchical cluster analysis showed two well-separated clusters between patients and controls, indicating that ET platelets had a characteristic 70-miRNA signature (P<0.0001), 68 of which were downregulated. According to the mutational status, three differentially expressed miRNAs, miR-15a (P=0.045), miR-150 (P=0.001) and miR-519a (P=0.036), were identified. A 40-miRNA signature was identified characterizing JAK2V617F-positive ET patients. Eight genes, whose interaction with the miRNAs could activate the JAK/STAT pathway were identified. An inverse correlation was observed between miRNAs expression and their target genes for SOCS1 and miR-221, SOCS3 and miR-221, SOCS3 and miR-203, and PTPN11 and miR-23a. All three miRNAs were upregulated in JAK2V617F-negative ET patients. SOCS1 and SOCS3 were validated as targets of miR-221 and miR-203, respectively. In summary, our study shows that platelets from JAK2V617F-negative ET patients harbor a specific miRNA signature that can participate in the modulation of the JAK/STAT pathway through regulation of key genes as SOCS1 and SOCS3.