BACKGROUND: Epidermal growth factor receptor (EGFR) gene mutation is closely related to the EGFR-TKI target treatment and prognosis of lung adenocarcinoma patients. The mutation status of EGFR is limited by tissue detection. The purpose of this study was to investigate the difference of EGFR mutants in plasmacirculating cell-free DNA (cfDNA) obtained from patients with non-small cell lung cancer (NSCLC) in three groups: pre-therapy, after traditional chemotherapy and targeted therapy. The aim of this study was to analyze whether the plasma cfDNA could effectively determine the EGFR mutations and monitor the drug resistant gene T790M, as well as its prognostic prediction value in patients with targeted therapy. METHODS: ARMS (amplification refractory mutation system)-PCR was used to detect EGFR mutations in 107 (50 of pre-therapy, 29 after traditional chemotherapy and 28 after targeted therapy) cases of paired plasma and tumor tissue specimens, followed by comparing their concordance. The sensitivity, specificity and the prognostic value of plasma cfDNA detection were also observed. RESULTS: The total rate of EGFR mutation was 56% (60/107) in all plasma samples and 77.6% (83/107) in corresponding tumor tissues. Completely the same mutants and wild-type EGFR were found in 68.2% cases of paired specimens. The sensitivity of plasma cfDNA detection was 72.3% and the specificity was up to 100%. Patients were sub-categorized according to therapy. The results showed that the highest consistent rate of cfDNA and tumor tissues was found in the group of pre-therapy (74%, 37/50). Whereas, the lowest consistent rate was observed in the targeted therapy group (57.1%, 16/28). It indicated that the targeted treatment could change the EGFR status in plasma cfDNA. Further analyses on inconsistent cases in this group revealed that 50% of them were compound EGFR mutations with T790M. Thereby, it suggested that targeted therapy might induce the emergence of drug resistance gene T790M. This speculation was confirmed by survival analyses. Based on plasma cfDNA results, patients with T790M mutant had significantly worse progression-free survival (PFS) and overall survival (OS). CONCLUSIONS For EGFR testing, ARMS-PCR on plasma cfDNA is a promising methodology with the highest specificity and effective sensitivity. It is useful for EGFR testing in patients before treatment, especially the late-stage patients. Simultaneously, plasma cfDNA could be used to monitor the drug resistant mutation, T790M status and predict prognosis after targeted therapy.
Adenocarcinoma ; blood ; drug therapy ; genetics ; mortality ; Adenocarcinoma of Lung ; Adult ; Aged ; Aged, 80 and over ; Cell-Free Nucleic Acids ; blood ; ErbB Receptors ; genetics ; Female ; Humans ; Lung Neoplasms ; blood ; drug therapy ; genetics ; mortality ; Male ; Middle Aged ; Molecular Targeted Therapy ; Mutation, Missense ; Prognosis

PURPOSE: The main objective of this study was to evaluate the association between polymorphisms of the target genes of pemetrexed and clinical outcomes in non-small cell lung cancer (NSCLC) patients treated with pemetrexed. MATERIALS AND METHODS: We assessed polymorphisms at 8 sites in 4 genes [thymidylate synthase (TS), dihydrofolate reductase (DHFR; 1610, 680, 317, intron 1), methylenetetrahydrofolate reductase (MTHFR; 677, 1298), glycinamide ribonucleotide formyl transferase (GARFT; 2255)] associated with pemetrexed metabolism using polymerase chain reaction, gene scanning, and restriction fragment length polymorphism analysis in 90 patients with adenocarcinoma of the lung. RESULTS: Survival was significantly longer with pemetrexed in patients with TS 3RGCC/3RGCC or 3RGGC/3RGGC compared with the other groups (PFS; 5.2 months vs. 3.7 months, p=0.03: OS; 31.8 months vs. 18.5 months, p=0.001). Patients with DHFR 680CC experienced fatigue more frequently (50% vs. 8.6%, p=0.008). Polymorphisms of MTHFR and GARFT were not significantly associated with clinical outcomes of pemetrexed. CONCLUSION: The TS genotype was associated with survival and one DHFR polymorphism was associated with fatigue in NSCLC patients treated with pemetrexed. Further large prospective studies are required to identify other biomarkers that affect patients being treated with pemetrexed for adenocarcinoma of the lung.
Adenocarcinoma/*drug therapy/*genetics/mortality ; Adult ; Aged ; Aged, 80 and over ; Antimetabolites, Antineoplastic/pharmacology/*therapeutic use/toxicity ; Female ; Glutamates/pharmacology/*therapeutic use/toxicity ; Guanine/*analogs & derivatives/pharmacology/therapeutic use/toxicity ; Humans ; Lung Neoplasms/*drug therapy/*genetics/mortality ; Male ; Methylenetetrahydrofolate Reductase (NADPH2)/genetics ; Middle Aged ; Pharmacogenetics ; Phosphoribosylglycinamide Formyltransferase/genetics ; *Polymorphism, Single Nucleotide ; Tetrahydrofolate Dehydrogenase/genetics ; Thymidylate Synthase/genetics

Transglutaminase 2 (TG2), a cross-linking enzyme, is involved in drug resistance and in the constitutive activation of nuclear factor kappa B (NF-kappaB). We investigated the association of non-small cell lung cancer (NSCLC) treatment efficacy with TG2 and NF-kappaB expression in 120 patients: 102 with adenocarcinoma and 18 with other histologic types. All patients underwent surgery; 88 received adjuvant chemotherapy, with 28 receiving platinum-based doublet chemotherapy as first-line treatment and 29 receiving epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI) therapy. Patients' TG2 and NF-kappaB expression values were calculated semiquantitatively. The median TG2 value was 50 (range, 0-300) and the median NF-kappaB value was 20 (range, 0-240). Disease-free survival did not differ between the low- and high-TG2 groups. Among patients who received palliative platinum-based doublet chemotherapy, progression free survival (PFS) was longer in the low-TG2 group than in the high-TG2 group (11.0 vs. 7.0 months; P=0.330). Among those who received EGFR-TKI therapy, PFS was also longer in the low-TG2 group than in the high-TG 2 group (11.0 vs. 2.0 months; P=0.013). Similarly, in EGFR wild-type patients treated with EGFR-TKI, PFS was longer in patients with low TG2 expression (9.0 vs. 2.0 months; P=0.013). TG2 expression levels can predict PFS in patients with NSCLC treated with EGFR-TKI.
Adenocarcinoma/*drug therapy/mortality/surgery ; Adult ; Aged ; Aged, 80 and over ; Antineoplastic Agents/therapeutic use ; Carcinoma, Non-Small-Cell Lung/*drug therapy/mortality/surgery ; Disease-Free Survival ; Female ; GTP-Binding Proteins/*biosynthesis ; Humans ; Lung Neoplasms/*drug therapy/mortality/surgery ; Male ; Middle Aged ; NF-kappa B/biosynthesis ; Protein Kinase Inhibitors/therapeutic use ; Receptor, Epidermal Growth Factor/*antagonists & inhibitors/genetics ; Transglutaminases/*biosynthesis ; Treatment Outcome