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Abstract: Patients with non-small cell lung cancer (NSCLC) who have activating epidermal growth factor receptor (EGFR) mutations benefit from treatment with EGFR-tyrosine kinase inhibitors (EGFR-TKIs), namely, gefitinib and erlotinib. However, these patients eventually develop resistance to EGFR-TKIs. About 50% of this acquired resistance may be the result of a secondary mutation in the EGFR gene, such as the one corresponding to T790M. In our previous study, we found that combined treatment with fulvestrant and gefitinib decreases the proliferation of H1975 NSCLC cells, compared to treatment with either fulvestrant or gefitinib alone; however, the molecular mechanism for the improved effects of the combination treatment are still unknown. In this study, we confirmed that fulvestrant increases the gefitinib sensitivity of H1975 cells and found that let-7c was most upregulated in the fulvestrant-treated cells. Our data revealed that let-7c increases gefitinib sensitivity by repressing RAS and inactivating the phosphoinositide 3-kinase (PI3K)/AKT and mitogen-activated extracellular signal-regulated kinase (MEK)/extracellular signal-regulated kinase (ERK) signaling pathways. Taken together, our findings suggest that let-7c plays an important role in fulvestrant-induced upregulation of gefitinib sensitivity in H1975 cells. [Copyright &y& Elsevier]

Abstract: Purposes: This study was conducted to assess the efficacy and toxicity of gefitinib as first line treatment in patients with advanced non-small-cell lung cancer (NSCLC). Methods: Tumor tissue, derived from either the original tumor or the metastatic or recurrent site was taken from chemo-naïve patients with advanced (stage IIIB, IV and recurrent) NSCLC. Tumor genomic DNA underwent direct sequencing for EGFR exons 18, 19, 20 and 21. Sixty-one patients received 250mg of gefitinib daily until disease progression or unacceptable toxicity. Results: Out of 61 patients, 26 patients (42.6%) were EGFR mutations and 11 patients were wild type, 24 patients were status unknown. One patient achieved complete remission (CR). While 17 patients achieved partial remission (PR) and 23 experienced stable disease (SD). There were 20 patients developed progressive disease (PD). The tumor response rate and disease control rate was 29.5 and 67.2%, respectively, and symptom remission rate was 66.7% as well. Median remission time was 9 days. Median over survival time was 13.0 months. Median progression-free survival time was 5.0 months. The MST of patients with EGFR mutation was 17.0 months, while the MST of patients with EGFR status unknown or wild type was 11.0 months. The PFS of patients with EGFR mutation was 9.0 months and it in EGFR status unknown or wild type was 2.5 months .The most common toxicity included rash (54.1%) and diarrhea (31.1%). Dehydration and pruritus of skin was observed in 31.1 and 26.2% of the patients respectively. Hepatic toxicity occurred in 8.2% of patients and oral ulceration occurred in six patients (9.8%). Conclusion: Single agent treatment with gefitinib is effective in patients with advanced NSCLC, especially in patients with EGFR mutation, and well tolerated in Chinese patients. [Copyright &y& Elsevier]