Abstract The epidermal growth factor receptor (EGFR) is a receptor tyrosine kinase of the ErbB family that is frequently overexpressed in non‐small cell lung cancer (NSCLC), and has been identified as a novel therapeutic target for lung cancer. The development of small molecule EGFR‐tyrosine kinase inhibitors (TKI) such as gefitinib and erlotinib has resulted in paradigm shift in the treatment of advanced NSCLC. The impact of EGFR‐TKI in the treatment of NSCLC is even greater in Asia–Pacific region because one of the greatest clinical benefits of EGFR‐TKI has been seen in patients of East Asian ethnicity. The discovery of somatic mutations in EGFR‐tyrosine kinase domain has so far answered some, but not all, of the questions regarding the clinical response to EGFR‐TKI in NSCLC. In addition, other molecular profiles such as KRAS mutations have also been found to play an important role in EGFR targeted therapy. In this article, we review EGFR targeted therapy in NSCLC with the focus on perspective from the Asia–Pacific region.
Introduction Treatment with epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) has been associated with favorable progression free survival (PFS) in patients with non-small cell lung cancers (NSCLC) harboring EGFR mutations. However, a subset of this population doesn't respond to EGFR-TKI treatment. Therefore, the present study aimed to elucidate survival outcome in NSCLC EGFR-mutant patients who were treated with EGFR TKIs. Methods Among the 580 consecutive NSCLC patients who were treated at our facility between 2008 and 2012, a total of 124 treatment-naïve, advanced NSCLC, EGFR-mutant patients treated with EGFR TKIs were identified and grouped into non-responders and responders for analyses. Results Of 124 patients, 104 (84%) responded to treatment, and 20 (16%) did not; and the overall median PFS was 9.0 months. Notably, the PFS, overall survival (OS) and survival rates were significantly unfavorable in non-responders (1.8 vs. 10.3 months, hazard ratio (HR) = 29.2, 95% confidence interval (CI), 13.48–63.26, P<0.0001; 9.4 vs. 17.3 months, HR = 2.74, 95% CI, 1.52–4.94, P = 0.0008; and 58% vs. 82% in 6, 37% vs. 60% in 12, and 19 vs. 40% at 24 months, respectively). In multivariate analysis, treatment efficacy strongly affected PFS and OS, independent of covariates (HR = 47.22, 95% CI, 17.88–124.73, P<0.001 and HR = 2.74, 95% CI, 1.43–5.24, P = 0.002, respectively). However, none of the covariates except of the presence of EGFR exon 19 deletion in the tumors was significantly associated with better treatment efficacy. Conclusions A subset of NSCLC EGFR-mutant patients displayed unfavorable survival despite EGFR TKI administration. This observation reinforces the urgent need for biomarkers effectively predicting the non-responders and for drug development overcoming primary resistance to EGFR TKIs. In addition, optimal therapeutic strategies to prolong the survival of non-responders need to be investigated.
Objective2-Methoxyestradiol (2ME2) has been shown to induce apoptosis in leukemic cells, but its exact mechanism remains unclear. Because c-Myc plays a critical role in leukemogenesis, we evaluated whether 2ME2 acts on acute myeloid leukemia (AML) through modulation of c-Myc activity.Materials and MethodsAML cell lines and primary AML leukemia were treated with 2ME2 and the relationship between 2ME2-induced apoptosis and changes in c-Myc activity was examined.Results2ME2 induced mitochondrial apoptosis of human AML cells through increased reactive oxygen species. Further investigation showed that 2ME2 downregulated c-Myc expression in a time-dependent manner. Increased oxidative stress led to downregulation of c-Myc mRNA and protein, but did not affect the stability of c-Myc protein. To demonstrate the role of c-Myc in 2ME2-induced apoptosis, we ectopically expressed wild-type c-Myc in AML cells and found that ectopic expression of c-Myc abrogated the 2ME2-induced apoptosis. In addition, we showed that 2ME2 treatment inhibited phosphorylation of Akt and binding of nuclear factor-κB p65/p50 heterodimers to its DNA targets. As with results from cell lines studied, 2ME2 also induced cytotoxicity to primary AML cells and downregulated their c-Myc expression and induced apoptosis.ConclusionDownregulation of c-Myc is critical for 2ME2-induced oxidative stress and apoptosis in AML cells. Our results might be extended to other types of cancers overexpressing c-Myc.
Human papillomavirus (HPV) has been implicated in multiple cancers, but its significance in lung cancer has remained controversial. As the prevalence of HPV 16/18 infection was higher in lung adenocarcinoma among Taiwanese females, the aim of our study was to evaluate the clinical impact of HPV infections in lung adenocarcinoma. Two hundred and ten patients were enrolled to investigate the associations of HPV status in tumors with clinical characteristics as well as its impact on overall survival. The methods to assess HPV status were by immunohistochemistry for HPV L1 capsid protein and E6 protein and by nested polymerase chain reaction for HPV 16 and HPV 18. HPV infections were identified in 35.2% of patients, and associated with localized and smaller sized tumors (p = 0.022 and p = 0.002, respectively). Patients with HPV infections had a significantly better survival (p = 0.023, by log-rank test) and a significantly reduced mortality risk after adjustments of age, tumor extent, epidermal growth factor receptor (EGFR) mutations status and treatments [adjusted hazard ratio = 0.68, 95% confidence interval (CI) = 0.49-0.96, p = 0.026, by multivariate Cox proportional hazards models]. Specifically, patients with both HPV infections and EGFR mutations had the best survival outcome [1-year survival rate, 68.5% (95% CI = 52.2-4.8%)]. Our findings indicate that HPV infections represent an independent prognostic factor for overall survival in patients with lung adenocarcinoma.
Cisplatin and carboplatin cause nephrotoxicity by forming platinum-DNA adducts and lead to cell death.One-hundred and sixteen Taiwanese lung cancer patients who received cisplatin or carboplatin more than twice were recruited, and their genotypes were determined. The risk of renal dysfunction, injury to the kidney, failure of kidney function, loss of kidney function, and end-stage kidney disease (RIFLE) criteria were used to evaluate the occurrence of nephrotoxicity. A logistic regression, multiple regression with a classification and regression tree (CART), and the Framingham study risk score were used to analyze interactions between genetic and nongenetic factors in producing platinum-induced nephrotoxicity.ERCC1 118C and TP53 72Arg polymorphisms were associated with increased risks of platinum-induced nephrotoxicity. Other risk factors found included the platinum type, baseline serum creatinine (Scr), coadministration of vinorelbine, and the number of chemotherapy cycles. The overall prediction rate of the CART was 82.7%, with a sensitivity of 0.630 and specificity of 0.896. The Framingham study risk prediction model contained 7 factors. Its prediction rate was 84.5%, with a sensitivity of 0.643 and specificity of 0.909.Genetic polymorphisms of ERCC1 and TP53 are risk factors for nephrotoxicity. The CART analysis may provide a clinically applicable model to predict the risk of cisplatin- and carboplatin-induced nephrotoxicity.
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