Predicting osimertinib‐treatment outcomes through EGFR mutant‐fraction monitoring in the circulating tumor DNA of EGFR T790M‐positive patients with non‐small cell lung cancer (WJOG8815L)

The WJOG8815L phase II clinical study involves patients with non‐small cell lung cancer (NSCLC) that harbored the EGFR T790M mutation, which confers resistance to EGFR tyrosine kinase inhibitors (TKIs). The purpose of this study was to assess the predictive value of monitoring EGFR genomic alterations in circulating tumor DNA (ctDNA) from patients with NSCLC that undergo treatment with the third‐generation EGFR‐TKI osimertinib. Plasma samples of 52 patients harboring the EGFR T790M mutation were obtained pretreatment (Pre), on day 1 of treatment cycle 4 (C4) or cycle 9 (C9), and at diagnosis of disease progression or treatment discontinuation (PD/stop). CtDNA was screened for EGFR‐TKI‐sensitizing mutations, the EGFR T790M mutation, and other genomic alterations using the cobas EGFR Mutation Test v2 (cobas), droplet digital PCR (ddPCR), and targeted deep sequencing. Analysis of the sensitizing—and T790M—EGFR mutant fractions (MFs) was used to determine tumor mutational burden. Both MFs were found to decrease during treatment, whereas rebound of the sensitizing EGFR MF was observed at PD/stop, suggesting that osimertinib targeted both T790M mutation‐positive tumors and tumors with sensitizing EGFR mutations. Significant differences in the response rates and progression‐free survival were observed between the sensitizing EGFR MF‐high and sensitizing EGFR MF‐low groups (cutoff: median) at C4. In conclusion, ctDNA monitoring for sensitizing EGFR mutations at C4 is suitable for predicting the treatment outcomes in NSCLC patients receiving osimertinib (Clinical Trial Registration No.: UMIN000022076).

Abbreviations

CIs

confidence intervals

ctDNA

circulating tumor DNA

ddPCR

droplet digital PCR

EGFR

epidermal growth factor receptor

MFs

mutant fractions

NGS

next‐generation sequencing

NSCLC

non‐small cell lung cancer

ORR

overall response rate

OS

overall survival

PD

progressive disease

PFS

progression‐free survival

PR

partial response

SD

stable disease

TKI

tyrosine kinase inhibitor

     

In silico repurposing the Rac1 inhibitor NSC23766 for treating PTTG1-high expressing clear cell renal carcinoma

The pituitary tumor-transforming gene 1 (PTTG1), also known as Securin, is considered an oncogene. This study aimed to investigate the role of PTTG1 in clear cell renal cell carcinoma (ccRCC) using in silico bioinformatics approaches. A pan-cancer analysis using The Cancer Genome Atlas (TCGA) data indicated that among all cancer types copy number amplification of PTTG1 gene was most frequently found in ccRCC. However, amplification of PTTG1 gene copy number did not correlate with the increase of mRNA level in ccRCC, and did not predict the patients' overall survival. Instead, ccRCC was correlated with overexpression of PTTG1 mRNA, and its expression level was stage-dependent increased in cancer patients. An outlier analysis using the Oncomine database suggested that PTTG1 mRNA expression served as a good biomarker for ccRCC. Pathway analysis for upregulated genes enriched in PTTG1-high expressing ccRCC patients found that PTTG1 overexpression was associated with mitotic defects. Mining drug sensitivity data using the Cancer Therapeutics Response Portal (CTRP) discovered that PTTG1-high expressing ccRCC cell lines were susceptible to a Rac1 (Ras-related C3 botulinum toxin substrate 1) inhibitor NSC23766. Therefore, this study provides an in silico insight into the role of PTTG1 in ccRCC, and repurposes the Rac1 inhibitor NSC23766 for treating PTTG1-high expressing ccRCC.     

EGFR抑制剂通过c-myc途径影响PD-L1在肺癌细胞中的表达

目的:以EGFR抑制剂为介质，研究EGFR/KRAS通路对人非小细胞肺癌A549和H1299细胞中免疫检查点抑制剂PD-L1表达的影响，探讨靶向治疗与免疫治疗联用在相关肿瘤临床治疗中的潜在价值。方法:Western blotting检测A549和H1299细胞经Erlotinib处理后细胞中c-myc的表达量变化； RT-PCR法检测Erlotinib对A549和H1299细胞中c-myc下游基因分化抗原簇47（cluster of differentiation 47，CD47）及PD-L1转录水平的调控，同时平行检测在c-myc基因沉默后，Erlotinib对CD47及PD-L1转录水平的调控；Western blotting检测Erlotinib用量与PD-L1表达的相关性；通过与肿瘤浸润T细胞（tumor infiltrating T cell，TIL-T）共培养，检测Erlotinib影响前后A549和H1299细胞对TIL-T细胞治疗的敏感度。结果:Erlotinib能显著下调c-myc在A549和H1299细胞内的表达量（P<0.01）；c-myc蛋白表达量受Erlotinib影响下调后，PD-L1的转录水平也受到了明显的影响（P<0.01），但Erlotinib对于c-myc沉默的A549和H1299细胞株中CD47及PD-L1的转录水平影响很小（P>0.05）；Erlotinib剂量对A549和H1299细胞中PD-L1的表达量呈现出显著的正相关性，但对c-myc沉默的细胞株影响不大（P>0.05），结果与转录水平一致；Erlotinib处理后，A549和H1299细胞对TIL-T细胞的抵抗能力显著降低，细胞凋亡信号caspase-3激活更加明显。结论:Erlotinib能通过EGFR通路调控c-myc在细胞中的表达水平，进而介导PD-L1表达水平降低，增强TIL-T细胞对A549和H1299细胞的杀伤能力。     

Survival Disparities in Black Patients With EGFR-mutated Non–small-cell Lung Cancer

BackgroundLittle is known about the difference between black and non-black patients with epidermal growth factor receptor (EGFR)-mutated non–small-cell lung cancer (NSCLC), particularly regarding survival. We thus characterized the EGFR expression profile, clinical characteristics, and survival outcome in these patients.Patient and MethodsWe reviewed the cancer registry and patient charts at a New York-Bronx network (n = 2773) treating a large population of minority patients, for non-squamous NSCLC (n = 1986) diagnosed between 2009 and 2015. Survival was adjusted for smoking, gender, age, weight, and stage.ResultsThe EGFR mutation rate was 15% (98/652) in tested patients (black, 14%; non-black, 16%). There was no significant difference between the 2 cohorts with respect to age at diagnosis, gender, presenting stages, and socioeconomic status. On the other hand, weight was noted to be heavier in black patients with EGFR-mutated NSCLC than their non-black counterparts (P = .012). After adjusting for gender, age, smoking status, weight, and stage, the multivariate analysis revealed no racial disparity in survival among patients with wild-type EGFR (P = .774); However, among patients with EGFR-mutated NSCLC, black patients had shorter survival in comparison with non-black patients (P = .001), with 2-year survival rates being 33% versus 61%, respectively. Such shorter survival was also observed among EGFR-inhibitor treated patients with common EGFR mutations (P = .040).ConclusionsTo our knowledge, this is the first report of inferior survival among black patients with NSCLC with EGFR mutations, relative to non-black patients. The survival disparities suggest the need of more tailored management for this patient population.