Acquired resistance to EGF receptor (EGFR) tyrosine kinase inhibitor (TKI) is a critical problem in the treatment of lung cancer. Although several mechanisms have been shown to be responsible for acquired resistance, all mechanisms have not been uncovered. In this study, we investigated the molecular and cellular profiles of the acquired resistant cells to EGFR-TKI in EGFR-mutant lung cancers. Four EGFR-mutant cell lines were exposed to gefitinib by stepwise escalation and high-concentration exposure methods, and resistant sublines to gefitinib were established. The molecular profiles and cellular phenotypes of these resistant sublines were characterized. Although previously reported, alterations including secondary EGFR T790M mutation, MET amplification, and appearance of epithelial-to-mesenchymal transition (EMT) features were observed, these 2 drug-exposure methods revealed different resistance mechanisms. The resistant cells with EMT features exhibited downregulation of miRNA-200c by DNA methylation. Furthermore, the HCC827-derived subline characterized by the high-concentration exposure method exhibited not only EMT features but also stem cell–like properties, including aldehyde dehydrogenase isoform 1 (ALDH1A1) overexpression, increase of side-population, and self-renewal capability. Resistant sublines with stem cell–like properties were resistant to conventional chemotherapeutic agents but equally sensitive to histone deacetylase and proteasome inhibitors, compared with their parental cells. ALDH1A1 was upregulated in clinical samples with acquired resistance to gefitinib. In conclusion, our study indicates that the manner of EGFR-TKI exposure influences the mechanism of acquired resistance and the appearance of stem cell–like property with EGFR-TKI treatment.
TAE226, a bis-anilino pyrimidine compound, has been developed as an inhibitor of focal adhesion kinase (FAK) and insulin-like growth factor-I receptor (IGF-IR). In this study, we investigated the effect of TAE226 on non-small-cell lung cancer (NSCLC), especially focusing on the EGFR mutational status. TAE226 was more effective against cells with mutant EGFR, including the T790M mutant, than against cells with wild-type one. TAE226 preferentially inhibited phospho-EGFR and its downstream signaling mediators in the cells with mutant EGFR than in those with wild-type one. Phosphorylation of FAK and IGF-IR was not inhibited at the concentration at which the proliferation of EGFR-mutant cells was inhibited. Results of the in vitro binding assay indicated significant differences in the affinity for TAE226 between the wild-type and L858R (or delE746_A750) mutant, and the reduced affinity of ATP to the L858R (or delE746_A750) mutant resulted in good responsiveness of the L858R (or delE746_A750) mutant cells to TAE226. Of interest, the L858R/T790M or delE746_A750/T790M mutant enhanced the binding affinity for TAE226 compared with the L858R or delE746_A750 mutant, resulting in the effectiveness of TAE226 against T790M mutant cells despite the T790M mutation restoring the ATP affinity for the mutant EGFR close to that for the wild-type. TAE226 also showed higher affinity of about 15-fold for the L858R/T790M mutant than for the wild-type one by kinetic interaction analysis. The anti-tumor effect against EGFR-mutant tumors including T790M mutation was confirmed in mouse models without any significant toxicity. In summary, we showed that TAE226 inhibited the activation of mutant EGFR and exhibited anti-proliferative activity against NSCLCs carrying EGFR mutations, including T790M mutation.
The discovery of an echinoderm microtubule-associated protein-like 4 (EML4)-anaplastic lymphoma kinase (ALK) fusion gene led to improved clinical outcomes in patients with lung cancer after the development of the first ALK-targeting agent, crizotinib. Some second-generation ALK tyrosine kinase inhibitors (TKIs), which might be more potent than crizotinib or effective on crizotinib-resistant patients, have been developed. Although these ALK-TKIs show an excellent response initially, most patients eventually acquire resistance. Therefore, careful consideration of the resistance mechanisms might lead to superior therapeutic strategies. Here, we summarize the history of ALK-TKIs and their underlying resistance mechanisms in both the preclinical and clinical settings. In addition, we discuss potential future treatment strategies in ALK-TKI-naïve and -resistant patients with lung cancer harboring the EML4-ALK fusion gene.
lung cancer; EML4-ALK; crizotinib; ceritinib; alectinib; resistance
In evaluation of the clinical benefit of a new targeted agent in a phase 3 trial enrolling molecularly selected patients with advanced non-small cell lung cancer (NSCLC), overall survival (OS) as an endpoint seems to be of limited use because of a high level of treatment crossover for ethical reasons. A more efficient and useful indicator for assessing efficacy is needed.
Methods and Findings
We identified 18 phase 3 trials in the literature investigating EGFR-tyrosine kinase inhibitor (TKIs) or ALK-TKIs, now approved for use to treat NSCLC, compared with standard cytotoxic chemotherapy (eight trials were performed in molecularly selected patients and ten using an “all-comer” design). Receiver operating characteristic analysis was used to identify the best threshold by which to divide the groups. Although trials enrolling molecularly selected patients and all-comer trials had similar OS-hazard ratios (OS-HRs) (0.99 vs. 1.04), the former exhibited greater progression-free survival-hazard ratios (PFS-HR) (mean, 0.40 vs. 1.01; P<0.01). A PFS-HR of 0.60 successfully distinguished between the two types of trials (sensitivity 100%, specificity 100%). The odds ratio for overall response was higher in trials with molecularly selected patients than in all-comer trials (mean: 6.10 vs. 1.64; P<0.01). An odds ratio of 3.40 for response afforded a sensitivity of 88% and a specificity of 90%.
The notably enhanced PFS benefit was quite specific to trials with molecularly selected patients. A PFS-HR cutoff of ∼0.6 may help detect clinical benefit of molecular targeted agents in which OS is of limited use, although desired threshold might differ in an individual trial.
Introduction: Programmed cell death protein 1 (PD-1) and programmed death-ligand 1 (PD-L1) play a major role in suppressing the immune system during the formation of the PD-1/PD-L1 pathway, which transmits an inhibitory signal to reduce T cell activity. PD-L1 is often expressed in various malignant tumors. In contrast, PD-1 is generally observed in activated lymphocytes and myeloid-derived dendritic cells. Of the malignant cells, only Jurkat cells under special conditions and angioimmunoblastic T-cell lymphoma tissue cells express PD-1 on their surface. Methods: To clarify whether the PD-1/PD-L1 pathway participates in the immunotolerance of small-cell lung cancer (SCLC) cells, we examined the expressions of PD-1 and PD-L1 on the cell surface of SCLC cell lines using flow cytometry and reverse transcription polymerase chain reaction. Results: Among the four SCLC cell lines examined, only SBC-3 expressed both PD-1 and PD-L1. Conclusions: We demonstrated that both PD-1 and PD-L1 molecules were co-expressed on the surface of SCLC cells. Although the biological implications of this remain unclear, we speculate that PD-1 and its ligand on the SCLC cells may participate in the growth inhibition of tumor cells as reported in cytotoxic T cells.
Small-cell lung cancer; cell line; PD-1; PD-L1; co-expression
The AIM of this study was to identify prognostic factors in patients receiving trimodality therapy for locally advanced non-small-cell lung cancer (NSCLC). Among patients who underwent induction chemoradiotherapy (CRT) followed by surgery between 1999 and 2011 at our institution, 76 NSCLC patients with clinical (c) N2/3 stage III were enrolled in this retrospective study. Induction CRT consisted of docetaxel and cisplatin with concurrent 40–60 Gy radiation therapy. In total, 76 patients were assessed (53 men and 23 women) with 43 adenocarcinomas and 33 non-adenocarcinomas. Of the 76 patients, 44 had cStage IIIA and 32 had cStage IIIB disease. The primary tumors were located in the right upper lobe (N=33), right middle lobe (N=5), right lower lobe (N=11), left upper lobe (N=20s) and left lower lobe (N=7). For all 76 patients, lower lobe tumors were associated with a significantly shorter overall survival (OS) and disease-free survival (DFS) compared to non-lower lobe tumors (OS, P=0.022; and DFS, P=0.0007). When the analysis was limited to pathologically proven N2/3 disease prior to induction CRT (n=36), lower lobe location, compared to other locations, tended to be a poor prognostic factor (OS, P=0.068; and DFS, P=0.0075). Our results indicated that a lower lobe tumor origin is associated with unfavorable prognosis in NSCLC patients treated with induction CRT, strongly suggesting the significance of appropriate patient selection in order to maximize the benefits of trimodality therapy.
non-small-cell lung cancer; induction chemoradiotherapy; surgery; N2 disease
Widespread use of generic drugs is considered to be indispensable if reductions in total health care costs are to be achieved, but the market share of such drugs remains low. In general, generic drugs have the same active ingredients as brand-name drugs, but this is not always the case. Thus, toxicity profiles may vary when brand-name and generic drugs are compared. We retrospectively investigated the incidence of hyponatremia in patients receiving brand-name cisplatin (CDDP) and a generic counterpart thereof.
We reviewed the medical records of patients treated with brand-name CDDP (n=53) and a generic formulation (n=26), and compared the incidences of hyponatremia and renal toxicity. Toxicities were graded using the Common Terminology Criteria for Adverse Events, version 4.0. Differences between groups were evaluated using the Student’s t-test, and the odds ratio for hyponatremia was estimated via logistic regression analysis.
Serum creatinine levels after chemotherapy increased significantly in both the brand-name and generic CDDP groups; no significant difference was evident between the two groups. Hyponatremia of grade 3 or above developed in 30.7% of the generic CDDP group compared to 15.1% of the brand-name CDDP group (P=0.011). Multivariate analysis showed that the use of generic CDDP increased the incidence of hyponatremia (odds ratio =5.661, 95% confidence interval =1.403–22.839; P=0.015).
Oncologists should be aware that use of a generic CDDP might be associated with more hyponatremia than would use of brand-name CDDP.
cisplatin; hyponatremia; brand-name; generic drug
Persistent phosphorylation of signal transducer and activator of transcription 3 (STAT3) has been demonstrated in 22%~65% of non-small cell lung cancers (NSCLC). STAT3 activation is mediated by receptor tyrosine kinases, such as epidermal growth factor receptor (EGFR) and MET, cytokine receptors, such as IL-6, and non-receptor kinases, such as Src. Overexpression of total or phosphorylated STAT3 in resected NSCLC leads to poor prognosis. In a preclinical study, overexpression of STAT3 was correlated with chemoresistance and radioresistance in NSCLC cells. Here, we review the role of STAT3 and the mechanisms of treatment resistance in malignant diseases, especially NSCLC. As STAT3 is a critical mediator of the oncogenic effects of EGFR mutations, we discuss STAT3 pathways in EGFR-mutated NSCLC, referring to mechanisms of EGFR tyrosine kinase inhibitor resistance.
signal transducer and activator of transcription 3; Janus kinase 2; epidermal growth factor receptor; non-small cell lung cancer; drug resistance
Rapid on-site evaluation (ROSE) is used widely during endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA). BIOEVALUATOR® is a device used for determining whether the tissues obtained by EBUS-TBNA are appropriate for a pathological diagnosis. This study describes our experience with ROSE using BIOEVALUATOR® during EBUS-TBNA for diagnosing pulmonary and mediastinal diseases.
MATERIALS AND METHODS:
We retrospectively evaluated the results of 35 patients who underwent EBUS-TBNA with BIOEVALUATOR® between December 2011 and February 2013. For the diagnosis, the tissue areas were appearing white and red through BIOEVALUATOR® are considered to be appropriate and inappropriate, respectively. We examined their medical records to obtain information concerning the examination of BIOEVALUATOR® results of the patient's materials (white/red), the diagnosis yield, site and size of lymph nodes and number of needle passes.
The median longest diameter of 40 lymph nodes (21 #7, 13 #4R, 4 #4L and 2 #11) from 35 patients was 27.9 (range 12.4-50.6) mm and the median number of needle passes was 2 (range 1-5). The definitive diagnosis was made by EBUS-TBNA in 28 of 35 patients, by thoracotomy in one patient and BIOEVALUATOR® results were white and lymphocytes were seen in the rest six patients. The BIOEVALUATOR® results of other patients without accurate diagnosis were left indefinitive. Finally, the six patients were judged as having benign lymphadenopathy because the lymph node size on computed tomography decreased or remained stable after for at least 8 months.
Checking aspirated samples using BIOEVALUATOR® appears useful for determining their adequacy for pathological diagnosis.
BIOEVALUATOR®; endobronchial ultrasound-guided transbronchial needle aspiration; rapid on-site evaluation
We encountered a family of Japanese descent in which multiple members developed lung cancer. Using whole-exome sequencing, we identified a novel germline mutation in the transmembrane domain of the human epidermal growth factor receptor 2 (HER2) gene (G660D). A novel somatic mutation (V659E) was also detected in the transmembrane domain of HER2 in one of 253 sporadic lung adenocarcinomas. Because the transmembrane domain of HER2 is considered to be responsible for the dimerization and subsequent activation of the HER family and downstream signaling pathways, we performed functional analyses of these HER2 mutants. Mutant HER2 G660D and V659E proteins were more stable than wild-type protein. Both the G660D and V659E mutants activated Akt. In addition, they activated p38, which is thought to promote cell proliferation in lung adenocarcinoma. Our findings strongly suggest that mutations in the transmembrane domain of HER2 may be oncogenic, causing hereditary and sporadic lung adenocarcinomas.
The purpose of this study was to compare the clinical outcomes of induction chemoradiotherapy and chemotherapy and to identify the prognostic factors for non-small-cell lung cancer patients with mediastinal lymph node metastasis who were treated with induction therapy.
Between August 1995 and December 2010, 50 non-small-cell lung cancer patients with pathological mediastinal lymph node metastasis were scheduled to receive induction therapy followed by surgery. Irinotecan plus cisplatin was used for induction chemotherapy from June 1995 to April 1999, and docetaxel plus cisplatin with concurrent radiation at a dose of 40–46 Gy has been used for induction chemoradiotherapy since May 1999.
Thirty-five patients were treated with induction chemoradiotherapy and 15 were treated with induction chemotherapy. For the entire population, the 3-year and 5-year overall survival rates were 64.1 and 53.9%, respectively, and the 1-year and 2-year disease-free survival rates were 70.0 and 53.1%, respectively. Among the clinicopathological factors, the chemoradiotherapy group exhibited longer overall survival and disease-free survival than the chemotherapy group (overall survival, P = 0.0020; disease-free survival, P = 0.015). Pathological downstaging was also significantly associated with favorable overall survival (P = 0.0042) and disease-free survival (P = 0.021). A multivariate analysis showed that chemoradiotherapy (P = 0.0099) and pathological downstaging (P = 0.039) were independent prognostic factors.
Our results indicated that induction chemoradiotherapy was superior to induction chemotherapy with regard to the outcome of non-small-cell lung cancer patients with mediastinal lymph node metastasis.
Lung cancer; Induction therapy; Chemoradiotherapy; Chemotherapy
The purpose of this study was to show the long-term outcome of induction chemoradiotherapy, using docetaxel and cisplatin with concurrent radiotherapy followed by surgery for non-small-cell lung cancer (NSCLC) with mediastinal nodal metastasis. Between January 2000 and July 2006, 22 consecutive NSCLC patients with pathologically proven mediastinal nodal metastasis were treated with tri-modality therapy. The regimen consisted of docetaxel and cisplatin plus concurrent radiation at a dose of 40–46 Gy. The induction therapy was followed by surgery 4–6 weeks later. The pulmonary resections were composed of a lobectomy in 19 patients, including 3 with a sleeve lobectomy, a bilobectomy in 2 patients and a left pneumonectomy in 1 patient. With a median follow-up duration of 8.7 years, the 3-year and 7-year overall survival (OS) rates for the entire population were 72.7 and 63.6%, respectively. Our results suggest that tri-modality therapy is promising for NSCLC patients with mediastinal nodal metastasis.
Non-small-cell lung cancer; Induction chemoradiotherapy; N2
A 72-year-old woman was referred to our hospital with Stage IV non-small-cell lung cancer (NSCLC). Chest computed tomography revealed a mass in the upper lobe of the right lung, with pleural effusion. Cytologic examination identified adenocarcinoma cells in the right pleural effusion. Furthermore, both a deletion mutation in exon 19 and a threonine–methionine substitution mutation at position 790 in exon 20 (T790M) were detected in the epidermal growth factor receptors (EGFR) in the malignant cells. As systemic chemotherapy consisting of carboplatin and pemetrexed or erlotinib proved ineffective, docetaxel monotherapy was initiated as a third-line treatment. Following salvage chemotherapy, her Eastern Cooperative Oncology Group performance status improved from 3 to 1, with tumor regression over 5 months. To the best of our knowledge, this is the first report of successful docetaxel treatment for a patient with NSCLC harboring the T790M EGFR-activating mutation identified before treatment with EGFR tyrosine kinase inhibitors.
non-small-cell lung cancer; EGFR mutation; pretreatment mutation; T790M; docetaxel
Treatment-related death (TRD) remains a serious problem in small-cell lung cancer (SCLC), despite recent improvements in supportive care. However, few studies have formally assessed time trends in the proportion of TRD over the past two decades. The aim of this study was to determine the frequency and pattern of TRD over time.
We examined phase 3 trials conducted between 1990 and 2010 to address the role of systemic treatment for SCLC. The time trend was assessed using linear regression analysis.
In total, 97 trials including nearly 25,000 enrolled patients were analyzed. The overall TRD proportion was 2.95%. Regarding the time trend, while it was not statistically significant, it tended to decrease, with a 0.138% decrease per year and 2.76% decrease per two decades. The most common cause of death was febrile neutropenia without any significant time trend in its incidence over the years examined (p = 0.139). However, deaths due to febrile neutropenia as well as all causes in patients treated with non-platinum chemotherapy increased significantly (p = 0.033).
The overall TRD rate has been low, but not negligible, in phase III trials for SCLC over the past two decades.
To examine the usefulness of trimodality therapy in patients with clinical T3 or T4 (cT3–4) locally advanced non–small cell lung cancer (LA-NSCLC).
Between 1997 and 2009, a total of 76 LA-NSCLC patients with cT3–4 underwent surgery. Among them, 36 patients underwent induction chemoradiotherapy with docetaxel and cisplatin plus concurrent radiation followed by surgery (IC group). The other 40 patients initially underwent surgery (IS group). The outcomes of the IC and IS groups were then investigated. To minimize possible biases caused by confounding treatment indications, we performed a retrospective cohort analysis by applying a propensity score (PS). Patients were divided into three groups according to PS tertiles, and comparisons between the IC and IS groups were made by PS tertile-stratified Cox proportional hazard models.
For the entire cohort, which had a median follow-up duration of 48 months, the 3- and 5-year overall survival rates were 83.8 and 78.9%, respectively, in the IC group, versus 66.8 and 56.5%, respectively, in the IS group (P = 0.0092). After adjustments for potentially confounding variables, the IC group continued to have a significantly longer overall survival than the IS group (P = 0.0045). In addition, when the analysis was limited to 52 patients with cT3–4N0 or N1 disease, the IC group had a significantly longer overall survival than the IS group after adjustments for confounding variables (P = 0.019).
Our study indicates that trimodality therapy is highly effective in patients with cT3–4 LA-NSCLC.
Electronic supplementary material
The online version of this article (doi:10.1245/s10434-012-2302-x) contains supplementary material, which is available to authorized users.
In advanced non-small-cell lung cancer (NSCLC), with the increasing number of active compounds available in salvage settings, survival after progression to first-line chemotherapy seems to have improved. A literature survey was conducted to examine whether survival post-progression (SPP) has improved over the years and to what degree SPP correlates with overall survival (OS).
Methods and Findings
Median progression-free survival (MPFS) time and median survival time (MST) were extracted in phase III trials of first-line chemotherapy for advanced NSCLC. SPP was pragmatically defined as the time interval of MST minus MPFS. The relationship between MPFS and MST was modeled in a linear function. We used the coefficient of determination (r2) to assess the correlation between them. Seventy trials with 145 chemotherapy arms were identified. Overall, median SPP was 4.7 months, and a steady improvement in SPP was observed over the 20 years (9.414-day increase per year; p<0.001) in parallel to the increase in MST (11.253-day increase per year; p<0.001); MPFS improved little (1.863-day increase per year). Overall, a stronger association was observed between MST and SPP (r2 = 0.8917) than MST and MPFS time (r2 = 0.2563), suggesting SPP and MPFS could account for 89% and 25% of the variation in MST, respectively. The association between MST and SPP became closer over the years (r2 = 0.4428, 0.7242, and 0.9081 in 1988–1994, 1995–2001, and 2002–2007, respectively).
SPP has become more closely associated with OS, potentially because of intensive post-study treatments. Even in advanced NSCLC, a PFS advantage is unlikely to be associated with an OS advantage any longer due to this increasing impact of SPP on OS, and that the prolongation of SPP might limit the original role of OS for assessing true efficacy derived from early-line chemotherapy in future clinical trials.
The patient was a 71-year-old man who underwent a right hemicolectomy for ascending colon cancer (pT3, pN1, pM0) and who opted not to receive adjuvant chemotherapy. Eight months later, multiple liver metastases occurred. He therefore received FOLFOX4 (5-fluorouracil/leucovorin and 85 mg/m2 oxaliplatin) therapy, up to a total of 5 courses, and showed a partial response. While receiving the sixth course of FOLFOX4, he complained of chest pain and systemic itching approximately 15 min after the start of chemotherapy. An electrocardiogram revealed typical signs of ischemia. Coronary arteriography showed that the coronary arteries were intact. Believing the chest pain to be merely coincidental, we continued with the same therapy. However, he again developed the same chest pain during the seventh cycle of FOLFOX4 and treatment was stopped. We concluded that the patient’s symptoms were due to acute coronary syndrome (ACS) associated with the FOLFOX4 regimen. Variant angina as a type of ACS is a rare adverse effect of FOLFOX4. Clinicians should be aware of this potential adverse effect when monitoring patients receiving FOLFOX4.
FOLFOX4; Acute coronary syndrome; Variant angina; Allergy
A 66-year-old Japanese man with pancreatic cancer received eleven courses of gemcitabine monotherapy. The tumor responded to gemcitabine until metastatic liver tumors progressed. Subsequently, he was treated with S-1, an oral fluoropyrimidine anticancer agent, as salvage chemotherapy. Forty-two days after initiating S-1, he presented with dyspnea and fever. Chest computed tomography showed diffuse interstitial lesions with thickening of the alveolar septa and ground glass opacity. Serum KL-6 level was elevated to 1,230 U/mL and he did not use any other drugs except insulin. Thus, the development of interstitial lung disease (ILD) was considered to be due to S-1. Arterial blood oxygen pressure was 49.6 Torr in spite of oxygen administration (5 L/min). Steroid therapy improved his symptoms and the interstitial shadows on chest radiograph. Although S-1-induced ILD has mostly been reported to be mild, clinicians should be aware that S-1 has the potential to cause fatal ILD.
Corticosteroid therapy; Interstitial lung disease; Pancreatic cancer; S-1
Obstructive jaundice sometimes may develop in association with advanced small-cell lung cancer (SCLC); however, SCLC initially presenting with obstructive jaundice is rare. This report presents the cases of two SCLC patients with obstructive jaundice at the initial diagnosis. A 64-year-old male presented with obstructive jaundice due to a tumor at the head of the pancreas. He was diagnosed with SCLC by transbronchial biopsy from a lung tumor in the left upper lobe. Another 74-year-old male was admitted with jaundice due to a tumor in the porta hepatis. He was also diagnosed with SCLC by a fine-needle aspiration biopsy of a lung tumor in the left lower lobe. Both cases were successfully treated with systemic chemotherapy after endoscopic retrograde biliary drainage.
small-cell lung carcinoma; jaundice; biliary obstruction; metastasis
Few studies have formally assessed whether treatment outcomes have improved substantially over the years for patients with extensive disease small-cell lung cancer (ED-SCLC) enrolled in phase III trials. The objective of the current investigation was to determine the time trends in outcomes for the patients in those trials.
Methods and Findings
We searched for trials that were reported between January 1981 and August 2008. Phase III randomized controlled trials were eligible if they compared first-line, systemic chemotherapy for ED-SCLC. Data were evaluated by using a linear regression analysis. Results: In total, 52 trials were identified that had been initiated between 1980 and 2006; these studies involved 10,262 patients with 110 chemotherapy arms. The number of randomized patients and the proportion of patients with good performance status (PS) increased over time. Cisplatin-based regimens, especially cisplatin and etoposide (PE) regimen, have increasingly been studied, whereas cyclophosphamide, doxorubicin, and vincristine–based regimens have been less investigated. Multiple regression analysis showed no significant improvement in survival over the years. Additionally, the use of a PE regimen did not affect survival, whereas the proportion of patients with good PS and the trial design of assigning prophylactic cranial irradiation were significantly associated with favorable outcome.
Conclusions and Significance
The survival of patients with ED-SCLC enrolled in phase III trials did not improve significantly over the years, suggesting the need for further development of novel targets, newer agents, and comprehensive patient care.
We analyzed MET protein and copy number in NSCLC with or without EGFR mutations untreated with EGFR tyrosine kinase inhibitors (TKIs). MET copy number was examined in 28 NSCLC and 4 human bronchial epithelial cell lines (HBEC) and 100 primary tumors using quantitative real-time PCR. Positive results were confirmed by array comparative genomic hybridization and fluorescence in-situ hybridization. Total and phospho-MET protein expression was determined in 24 NSCLC and 2 HBEC cell lines using Western blot. EGFR mutations were examined for exon 19 deletions, T790M, and L858R. Knockdown of EGFR with siRNA was performed to examine the relation between EGFR and MET activation. High-level MET amplification was observed in 3 of 28 NSCLC cell lines and in 2 of 100 primary lung tumors that had not been treated with EGFR-TKIs. MET protein was highly expressed and phosphorylated in all the 3 cell lines with high MET amplification. In contrast, 6 NSCLC cell lines showed phospho-MET among 21 NSCLC cell lines without MET amplification (p = 0.042). Furthermore, those 6 cell lines harboring phospho-MET expression without MET amplification were all EGFR mutant (p = 0.0039). siRNA-mediated knockdown of EGFR abolished phospho-MET expression in examined 3 EGFR mutant cell lines of which MET gene copy number was not amplified. By contrast, phospho-MET expression in 2 cell lines with amplified MET gene was not down-regulated by knockdown of EGFR. Our results indicated that MET amplification was present in untreated NSCLC and EGFR mutation or MET amplification activated MET protein in NSCLC.
MET; amplification; EGFR; gefitinib; lung cancer
We investigated EGFR and KRAS alterations among atypical adenomatous hyperplasia and small lung adenocarcinomas with bronchioloalveolar features to understand their role during multistage pathogenesis.
Sixty lesions measuring 2 cm or less were studied, including 38 noninvasive lesions (4 atypical adenomatous hyperplasias, 19 Noguchi type A and 15 type B) and 22 invasive lesions (type C) based on the World Health Organization classification and Noguchi’s criteria. EGFR and KRAS mutations were examined using PCR-based assays. EGFR copy number was evaluated using fluorescence in situ hybridization.
EGFR and KRAS mutations were found in 26 (43.3%) and 5 (8.3%) lesions, respectively. Increased EGFR copy number status was identified in 10 lesions (16.7%), both mutant and wild type. EGFR or KRAS mutations were present in 39.5% and 7.9% (respectively) of noninvasive lesions and 50% or 9.1% (respectively) of invasive lesions. EGFR copy number was increased in 7.9% and 31.8% of noninvasive and invasive lesions (P = 0.029). Multivariate analysis revealed that increased EGFR copy number was the only significant factor to associate with invasive lesions (P = 0.035).
EGFR and KRAS mutations occur early during the multistage pathogenesis of peripheral lung adenocarcinomas. By contrast, increased EGFR copy number is a late event during tumor development and plays a role in the progression of lung adenocarcinoma independent of the initiating molecular events.
Multistage pathogenesis; EGFR; KRAS; Mutation; Amplification
The whole blood interferon-gamma assay (QuantiFERON-TB-2G; QFT) has not been fully evaluated as a baseline tuberculosis screening test in Japanese healthcare students commencing clinical contact. The aim of this study was to compare the results from the QFT with those from the tuberculin skin test (TST) in a population deemed to be at a low risk for infection with Mycobacterium tuberculosis.
Healthcare students recruited at Okayama University received both the TST and the QFT to assess the level of agreement between these two tests. The interleukin-10 levels before and after exposure to M tuberculosis-specific antigens (early-secreted antigenic target 6-kDa protein [ESAT-6] and culture filtrate protein 10 [CFP-10]) were also measured. Of the 536 healthcare students, most of whom had been vaccinated with bacillus-Calmette-Guérin (BCG), 207 (56%) were enrolled in this study. The agreement between the QFT and the TST results was poor, with positive result rates of 1.4% vs. 27.5%, respectively. A multivariate analysis also revealed that the induration diameter of the TST was not affected by the interferon-gamma concentration after exposure to either of the antigens but was influenced by the number of BCG needle scars (p = 0.046). The whole blood interleukin-10 assay revealed that after antigen exposure, the median increases in interleukin-10 concentration was higher in the subgroup with the small increase in interferon-gamma concentration than in the subgroup with the large increase in interferon-gamma concentration (0.3 vs. 0 pg/mL; p = 0.004).
As a baseline screening test for low-risk Japanese healthcare students at their course entry, QFT yielded quite discordant results, compared with the TST, probably because of the low specificity of the TST results in the BCG-vaccinated population. We also found, for the first time, that the change in the interleukin-10 level after exposure to specific antigens was inversely associated with that in the interferon-gamma level in a low-risk population.