RESUMO
BACKGROUND: Transcriptomic subtyping holds promise for personalized therapy in extensive-stage small-cell lung cancer (ES-SCLC). In this study, we aimed to assess intratumoral transcriptomic subtype diversity and to identify biomarkers of long-term chemoimmunotherapy benefit in human ES-SCLC. PATIENTS AND METHODS: We analyzed tumor samples from 58 ES-SCLC patients enrolled in two multicenter single-arm phase IIIb studies evaluating front-line chemoimmunotherapy in Spain: n=32 from the IMfirst trial, and n=26 from the CANTABRICO trial. We utilized the GeoMxTM DSP system to perform multi-region transcriptomic analysis. For subtype classification, we performed hierarchical clustering using the relative expression of ASCL1 (SCLC-A), NEUROD1 (SCLC-N), POU2F3 (SCLC-P), and YAP1 (SCLC-Y). RESULTS: Subtype distribution was similar between both cohorts, except for SCLC-P, not identified in the CANTABRICO_DSP cohort. A total of 44% of the patients in both cohorts had tumors with multiple co-existing transcriptional subtypes. Transcriptional subtypes or subtype heterogeneity were not associated with outcomes. Most potential targets did not show subtype-specific expression. Consistently in both cohorts, tumors from patients with long-term benefit (time to progression ³12 months) contained an IFNg-dominated mRNA profile, including enhanced capacity for antigen presentation. Hypoxia and glycolytic pathways were associated with resistance to chemoimmunotherapy. CONCLUSIONS: This work suggests that intratumoral heterogeneity, inconsistent association with outcome, and unclear subtype-specific target expression might be significant challenges for subtype-based precision oncology in SCLC. Pre-existing IFNg-driven immunity and mitochondrial metabolism seem correlates of long-term efficacy in this study, although the absence of a chemotherapy control arm precludes concluding that these are predictive features specific for immunotherapy.
RESUMO
Several platforms for noninvasive EGFR testing are currently used in the clinical setting with sensitivities ranging from 30% to 100%. Prospective studies evaluating agreement and sources for discordant results remain lacking. Herein, seven methodologies including two next-generation sequencing (NGS)-based methods, three high-sensitivity PCR-based platforms, and two FDA-approved methods were compared using 72 plasma samples, from EGFR-mutant non-small-cell lung cancer (NSCLC) patients progressing on a first-line tyrosine kinase inhibitor (TKI). NGS platforms as well as high-sensitivity PCR-based methodologies showed excellent agreement for EGFR-sensitizing mutations (K = 0.80-0.89) and substantial agreement for T790M testing (K = 0.77 and 0.68, respectively). Mutant allele frequencies (MAFs) obtained by different quantitative methods showed an excellent reproducibility (intraclass correlation coefficients 0.86-0.98). Among other technical factors, discordant calls mostly occurred at mutant allele frequencies (MAFs) ≤ 0.5%. Agreement significantly improved when discarding samples with MAF ≤ 0.5%. EGFR mutations were detected at significantly lower MAFs in patients with brain metastases, suggesting that these patients risk for a false-positive result. Our results support the use of liquid biopsies for noninvasive EGFR testing and highlight the need to systematically report MAFs.
Assuntos
Análise Mutacional de DNA/métodos , Mutação/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Biópsia , Estudos de Coortes , DNA de Neoplasias/genética , DNA de Neoplasias/isolamento & purificação , Receptores ErbB/genética , Éxons/genética , Feminino , Frequência do Gene/genética , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Sensibilidade e Especificidade , Deleção de Sequência/genéticaRESUMO
The discovery of endothelial growth factor receptor (EGFR) mutations has laid the foundations for personalized medicine in non-small cell lung carcinoma (NSCLC). In phase III trials, the first-generation tyrosine kinase inhibitors (TKI), gefitinib and erlotinib, demonstrated greater efficacy compared with chemotherapy in patients with EGFR mutations, achieving progression-free survival of 8-13.5 months. Afatinib, a second-generation irreversible pan-ErbB inhibitor, is the first TKI that has shown a benefit in overall survival (OS) compared with chemotherapy in EGFR mutation-positive NSCLC when used as first-line treatment. Exon 19 deletion (Del19) and the single-point substitution mutation (L858R) in exon 21, called activating mutations due to their ability to confer sensitivity to TKI, represent approximately 90% of the EGFR mutations in NSCLC. Distinct sensitivity to TKI has been observed depending on the type of mutation, with greater progression-free survival in patients with the Del19 mutation. The analysis of OS in the LUX-Lung 3 and LUX-Lung 6 trials showed a statistically significant increase in survival in afatinib-treated patients with the Del 19 mutation, but no significant increase in that of patients with the L858R mutation. Direct comparison of afatinib and gefitinib as first-line therapy (LUX-Lung 7 trial) showed a statistically-significant increase in progression-free survival (hazard ratio: 0.73; 95% confidence interval, 0.57-0.95; p=0.0165) with afatinib. In the analysis by type of mutation, this benefit was observed for both the Del19 and the L858R mutations.