EGFR exon 19-deletion aberrantly regulate ERCC1 expression that may partly impaired DNA damage repair ability in non-small cell lung cancer

Background Epidermal growth factor receptor (EGFR) activating mutations are usually associated with DNA damage repair (DDR) deficiency. However, the precise mechanism has remained elusive. In this study, we aimed to investigate whether EGFR exon 19 deletion mutation downstream signals contributed to DDR deficiency by downregulation of excision repair cross-complementation group-1 (ERCC1), a key factor in DDR, expression and function. Methods We first measured cell survival, DNA damage (gamma-H2AX foci formation) and damage repair (ERCC1 and RAD51 foci formation) ability in response to DNA cross-linking drug in EGFR exon 19 deletion and EGFR wild-type cells separately. We then investigated the involvement of EGFR downstream signals in regulating ERCC1 expression and function in EGFR exon 19 deletion cells as compared with EGFR wild-type ones. Results We observed increased gamma-H2AX, but impaired ERCC1 and RAD51 nuclear foci formation in EGFR exon 19 deletion cells as compared with EGFR wild-type ones treated with DNA cross-linker. In addition, we identified that inhibition of EGFR exon 19 deletion signals increased ERCC1 expression, whereas blocked wild-type EGFR signals decreased ERCC1 expression, on both mRNA and protein levels. Furthermore, EGFR exon 19 deletion downstream signals not only inhibited ERCC1 expression but also influenced ERCC1 foci formation in response to DNA cross-linker. Conclusion Our findings indicated that the aberrant EGFR exon 19 deletion signals were not only associated with decreased expression of ERCC1 but were also involved in impaired ERCC1 recruitment in response to DNA cross-link damage, thereby providing us with more evidence for exploring the mechanism of DDR deficiency in EGFR mutant NSCLC.Peer reviewe

Next-generation sequencing of homologous recombination genes could predict efficacy of platinum-based chemotherapy in non-small cell lung cancer

BackgroundWith the widespread use of next-generation sequencing (NGS) in clinical practice, an increasing number of biomarkers that predict a response to anti-tumor therapy in non-small cell lung cancer (NSCLC) has been identified. However, validated biomarkers that can be used to detect a response to platinum-based chemotherapy remain unavailable. Several studies have suggested that homologous recombination deficiency (HRD) may occur in response to platinum-based chemotherapy in ovarian cancer and breast cancer. However, currently there is a lack of proven and reliable HRD markers that can be used to screen for patients who may benefit from platinum-based chemotherapy, especially in NSCLC.MethodsNGS was used to screen for gene mutations, including homologous recombination (HR) genes and common driver gene mutations in NSCLC. Cox regression analysis was performed to identify potential clinicopathological or gene mutation factors associated with survival in patients receiving platinum-based chemotherapy, while Kaplan–Meier analysis with the log-rank test was performed to assess the effect of HR gene mutations on progression-free survival (PFS).ResultsIn a retrospective cohort of 129 patients with advanced NSCLC, 54 who received platinum-based chemotherapy with or without anti-angiogenic therapy were included in the analysis. Univariate and multivariate Cox proportional hazard regression analyses showed that HR gene mutations were associated with platinum-based chemotherapy sensitivity. Efficacy results indicated that the objective response rates (ORR) for patients with BRCA1/2 mutations and BRCA1/2 wild type were 75% and 30.4% (p=0.041), while the median PFS was 7.5 and 5.5 months (hazard ratio [HR], 0.52; 95% CI, 0.27–1.00; p=0.084), respectively. The ORRs of patients with HR gene mutations and HR gene wild type were 60% and 23.6% (p=0.01), and the median PFS was 7.5 and 5.2 months (HR, 0.56; 95% CI, 0.32–0.97; p=0.033), respectively.ConclusionsHR gene mutations show potential as promising biomarkers that may predict sensitivity to platinum-based chemotherapy in advanced and metastatic NSCLC

Allelic imbalances of chromosomes 8p and 18q and their roles in distant relapse of early stage, node-negative breast cancer

INTRODUCTION: Identification of breast cancer patients at risk for postoperative distant relapse is an important clinical issue. Existing pathological markers can predict disease recurrence only to a certain extent, and there is a need for more accurate predictors. METHODS: Using 'counting alleles', a novel experimental method, we determined allelic status of chromosomes 8p and 18q in a case-control study with 65 early stage, node negative, invasive ductal carcinomas (IDCs). The association between allelic imbalance (AI) of both chromosomal markers and distant relapses was examined. RESULTS: Eighty percent of tumors contained 8pAI and sixty-eight percent of tumors contained 18qAI. However, none of the tumor samples retained both chromosome 8p and 18q alleles. More importantly, tumors with 8pAI but not 18qAI were more likely to have distant relapse compared to tumors with 18qAI but not 8pAI. CONCLUSION: Our finding suggests that differential allelic loss of chromosomes 8p and 18q may represent subtypes of early stage IDC with different tumor progression behaviors

Detection and Clinical Significance of Abundance of EGFR Mutation

Non-small cell lung cancer (NSCLC) patients, with sensitive epidermal growth factor receptor (EGFR) mutations react well to tyrosine kinase inhibitors (TKIs). However, the efficacy of TKIs on patients with the same mutant types differs dramatically. It is implied that the different quantities of mutant alleles could be one of the reasons underlying. Patients with high abundance of EGFR mutation might benefit more from TKIs. There are no universal standards for the definition of EGFR mutant abundance. Abundance could be semi-quantified according to the different sensitivities of detection methods, quantified with quantifying detection techniques such as digital PCR or next generation sequencing, or quantified based on the expression of mutant proteins. The different abundances of primary and metastatic diseases could reflect the heterogeneity of the tumors. The pre-treatment level or the dynamic change of EGFR mutant abundance could help observe the course of the diseases and predict the efficacy of TKIs. TKIs resistance could be detected by change of abundance prior to image manifestations. Besides, the abundance of T790M could also predict drug efficacy and resistance of the first and third generation TKIs. Thus the detection of EGFR mutant abundance has important clinical significance. The standardization and correction of abundance needs more exploration

Advances in Double Mutations of EGFR and ALK Gene in Non-small Cell Lung Cancer

Molecular target therapy is one of the most popular field of non-small cell lung cancer (NSCLC) treatmnet. Epidermal growth factor receptor (EGFR) mutation and anaplastic lymphoma kinase (ALK) rearragement are the most important two oncogenic drivers in NSCLC, early studies suggested that EGFR mutations and ALK rearrangements are mutually exclusive, but isolated cases or small sample research with concomitant EGFR and ALK alterations have been constantly reported. The co-occurrence of EGFR mutations and anaplastic lymphoma kinase (ALK) rearrangements constitutes a rare molecular, the frequency of EGFR/ALK co-alterations was about 1%, however, little has been known about clinicopathologic feature and treatment. This review summarized published case report, EGFR and ALK alterations are common in female, Asian origin, never smoker, IV stage, and denocarcinomas. First-line treatment can choose EGFR or ALK tyrosine kinase inhibitors (TKIs). However, studies about the origin and resistance mechanism in EGFR/ALK co-alterations are little, require more experimental and clinical research

Clinical Development of Immunotherapy for Small Cell Lung Cancer

Small cell lung cancer (SCLC), which accounts for about 15% of lung cancer cases, is an aggressive disease characterized by rapid growth and early widespread metastasis. Despite sensitive to chemotherapy and radiotherapy, SCLC is vulnerable to get resistant and has high recurrence rates. In recent years, immunotherapy has shown good antitumor activity, especially programmed death receptor-1/ligand-L1 (PD-1/L1) and cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) Checkpoint inhibitors have changed the pattern of tumor treatment, and SCLC has high immunogenicity, high mutation load and other favorable immune factors, so immuno-checkpoint inhibitors may become an important breakthrough in SCLC treatment. This article will briefly review the clinical research of immunotherapy for small cell lung cancer