The combination of osimertinib with Raf inhibitor overcomes osimertinib resistance induced by KRAS amplification in EGFR-mutated lung cancer cells.

Osimertinib is a third-generation epidermal growth factor receptor (EGFR)1 tyrosine kinase inhibitor (TKI) approved for the treatment of EGFR-positive patients exhibiting a T790 M resistance mutation after treatment with an earlier generation of EGFR TKIs. However, resistance to osimertinib inevitably develops despite its efficacy, and the resistance mechanisms are complex and not fully understood. We established cell lines with acquired resistance to osimertinib from gefitinib- or erlotinib-resistant NSCLC cells using a dose-escalation method, and found that they had upregulated levels of phosphorylated ERK1/2. Targeted next-generation sequencing of 143 genes was performed, and interestingly, amplification of KRAS was observed in osimertinib-resistant cells. Transfection of siRNA against the KRAS gene notably reduced the activation of ERK1/2 and AKT and significantly enhanced the induction of apoptosis by osimertinib treatment in osimertinib-resistant cells. LY3009120, a RAF inhibitor, showed a significant synergistic effect with osimertinib on apoptotic cell death in osimertinib-resistant cells. Combined treatment with osimertinib and LY3009120 also demonstrated remarkable synergistic anti-tumor activity in mouse xenografts of these cells. This could be a potential new treatment option for KRAS amplification-induced osimertinib failure.

The combination of irreversible EGFR TKIs and SAHA induces apoptosis and autophagy-mediated cell death to overcome acquired resistance in EGFR T790M-mutated lung cancer.

To overcome T790M-mediated acquired resistance of lung cancer cells to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR TKIs), second generation TKIs such as BIBW2992 (afatinib) and third generation TKIs including WZ4002 have been developed. However, clinical data on their efficacy in treating T790M mutant tumors are lacking. Histone deacetylase (HDAC) inhibitors have been reported to arrest cell growth and to lead to differentiation and apoptosis of various cancer cells, both in vitro and in vivo. In the present study, we assessed whether the combination of suberoylanilide hydroxamic acid (SAHA, vorinostat), a potent HDAC inhibitor, and BIBW2992 or WZ4002 could overcome EGFR TKI resistance associated with T790M mutation in lung cancer cells. While treatment with BIBW2992 or WZ4002 alone slightly reduced the viability of PC-9G and H1975 cells, which possess T790M mutation, combining them with SAHA resulted in significantly decreased cell viability through the activation of the apoptotic pathway. This combination also enhanced autophagy occurrence and inhibition of autophagy significantly reduced the apoptosis induced by the combination treatment, showing that autophagy is required for the enhanced apoptosis. Caspase-independent autophagic cell death was also induced by the combination treatment with SAHA and either BIBW2992 or WZ4002. Finally, the combined treatment with SAHA and either BIBW2992 or WZ4002 showed an enhanced anti-tumor effect on xenografts of H1975 cells in vivo. In conclusion, the combination of new generation EGFR TKIs and SAHA may be a new strategy to overcome the acquired resistance to EGFR TKIs in T790M mutant lung cancer.

Family caregivers' awareness of illness and attitude toward disclosure during chemotherapy for advanced cancer.

OBJECTIVE: We investigated family caregivers' awareness of disease status and attitude toward disclosure of disease progression compared with those of cancer patients and explored the potential association between family caregivers' attitudes and patients' quality of life (QOL). METHODS: We carried out a survey using self-administered questionnaires answered by pairs of family caregivers and patients diagnosed with advanced cancer (n = 136 pairs). To assess patients' QOL, we used the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire. RESULTS: More than half of family caregivers (54%) did not have full knowledge of patients' advanced stage and goal of therapy. Positive attitudes toward disclosure were less common in family caregivers than in patients (59.4% and 85.4%, respectively; p < 0.01). The family caregivers' positive attitudes toward disclosure were inversely associated with patients' low functional scores (emotion [p = 0.04] and cognition [p = 0.02]) and high symptom scores (nausea and vomiting, pain, and insomnia; p < 0.05). However, in most QOL scales, patients' attitudes were not significantly associated with functioning and symptom scores. CONCLUSIONS: A large portion of family caregivers may not know the patients' exact status. This study also suggests that the family caregivers' attitudes may differ from patients' and may be associated with patients' QOL.

Downregulation of TRIB3 enhances the sensitivity of lung cancer cells to amino acid deprivation by suppressing AKT activation.

Tribbles pseudokinase 3 (TRIB3), a member of the mammalian Tribbles family, is implicated in multiple biological processes. This study aimed to investigate the biological functions of TRIB3 in lung cancer and its effect on amino acid-deprived lung cancer cells. TRIB3 mRNA expression was elevated in lung cancer tissues and cell lines compared to normal lung tissues and cells. TRIB3 knockdown markedly reduced the viability and proliferation of H1299 lung cancer cells. Deprivation of amino acids, particularly arginine, glutamine, lysine, or methionine, strongly increased TRIB3 expression via ATF4 activation in H1299 lung cancer cells. Knockdown of TRIB3 led to transcriptional downregulation of ATF4 and reduced AKT activation induced by amino acid deprivation, ultimately increasing the sensitivity of H1299 lung cancer cells to amino acid deprivation. Additionally, TRIB3 knockdown enhanced the sensitivity of H1299 cells to V-9302, a competitive antagonist of transmembrane glutamine flux. These results suggest that TRIB3 is a pro-survival regulator of cell viability in amino acid-deficient tumor microenvironments and a promising therapeutic target for lung cancer treatment.

mTOR inhibitors radiosensitize PTEN-deficient non-small-cell lung cancer cells harboring an EGFR activating mutation by inducing autophagy.

Clinical resistance to gefitinib, an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI), in patients with lung cancer has been linked to acquisition of the T790M resistance mutation in activated EGFR or amplification of MET. Phosphatase and tensin homolog (PTEN) loss has been recently reported as a gefitinib resistance mechanism in lung cancer. The aim of this study was to evaluate the efficacy of radiotherapy in non-small-cell lung cancer (NSCLC) with acquired gefitinib resistance caused by PTEN deficiency to suggest radiotherapy as an alternative to EGFR TKIs. PTEN deficient-mediated gefitinib resistance was generated in HCC827 cells, an EGFR TKI sensitive NSCLC cell line, by PTEN knockdown with a lentiviral vector expressing short hairpin RNA-targeting PTEN. The impact of PTEN knockdown on sensitivity to radiation in the presence or absence of PTEN downstream signaling inhibitors was investigated. PTEN knockdown conferred acquired resistance not only to gefitinib but also to radiation on HCC827 cells. mTOR inhibitors alone failed to reduce HCC827 cell viability, regardless of PTEN expression, but ameliorated PTEN knockdown-induced radioresistance. PTEN knockdown-mediated radioresistance was accompanied by repression of radiation-induced cytotoxic autophagy, and treatment with mTOR inhibitors released the repression of cytotoxic autophagy to overcome PTEN knockdown-induced radioresistance in HCC827 cells. These results suggest that inhibiting mTOR signaling could be an effective strategy to radiosensitize NSCLC harboring the EGFR activating mutation that acquires resistance to both TKIs and radiotherapy due to PTEN loss or inactivation mutations.

The Combination of Trametinib, a MEK Inhibitor, and Temsirolimus, an mTOR Inhibitor, Radiosensitizes Lung Cancer Cells.

BACKGROUND/AIM: We evaluated the radiosensitizing effect of the combination treatment of trametinib, a MEK inhibitor, and temsirolimus, an mTOR inhibitor, on non-small-cell lung carcinoma (NSCLC) cells. MATERIALS AND METHODS: The effects of combining trametinib and temsirolimus with radiation in NSCLC cell lines were evaluated using clonogenic survival and apoptosis assays. DNA double-strand breaks and cell cycle distribution were analyzed using flow cytometry. Tumor volume was measured to determine the radiosensitivity in lung cancer xenograft models. RESULTS: Exposure of lung cancer cells to a combination of trametinib and temsirolimus reduced clonogenic survival and promoted radiation-induced apoptosis. Combined inhibition of MEK and mTOR induced prolonged expression of γH2AX after irradiation and resulted in prolonged G2/M cell cycle arrest after irradiation in A549 cells. In vivo studies revealed that co-administration of the drugs sensitizes lung cancer xenografts to radiotherapy. CONCLUSION: The combination of trametinib and temsirolimus can enhance lung cancer radiosensitivity in vitro and in vivo.

Association of EGFR mutations in second primary lung cancer and HER2 expression in breast cancer survivors.

BACKGROUND: The incidence of second primary lung cancer (SPLC) is increasing with longer survival rates from breast cancer. Despite of studies to suggest the mutual exclusivity of epidermal growth factor receptor (EGFR) and human epidermal growth receptor 2 (HER2) in several cancers, the effect of HER2 expression in breast cancer on EGFR mutations in SPLC is unclear. Therefore, this study aimed to determine the association between HER2 expression and EGFR mutations. METHODS: We conducted a retrospective cohort study of breast cancer survivors diagnosed with SPLC after breast cancer treatment between 1997 and 2018. We investigated the association between HER2 expression in breast cancer and EGFR mutations in SPLC, specifically focusing on negative correlations by using logistic regression analysis. RESULTS: EGFR mutations in SPLC were detected in 19 of 38 patients. Analysis for HER2 revealed a statistically significant difference in the proportion of EGFR mutations between patients with SPLC and previous HER2 positive breast cancer (43.5%) and those with SPLC and previous HER2 negative breast cancer (90.0%; P=0.021). The ratio of EGFR mutations decreased with the degree of HER2 expression in patients with previous breast cancer (90.0%: for no HER2 expression, 62.5% for HER2 1+, 0.0% for HER2 2+, and 41.7% for HER2 3+; P=0.018). Multivariate logistic analyses revealed that EGFR mutations in SPLC were significantly associated with age [odds ratio (OR): 1.11, 95% confidence interval (CI): 1.01-0.23, P=0.039] and HER2 positive status (OR: 0.04, 95% CI: 0.01-0.56, P=0.017). CONCLUSIONS: This study suggests that the frequency of EGFR mutations in SPLC may be associated with low HER2 expression in previous breast cancer.

Real-world outcomes of anti-PD1 antibodies in platinum-refractory, PD-L1-positive recurrent and/or metastatic non-small cell lung cancer, and its potential practical predictors: first report from Korean Cancer Study Group LU19-05.

PURPOSE: Although immune-checkpoint inhibitors have become a new therapeutic option for recurrent/metastatic non-small cell lung cancers (R/M-NSCLC), its clinical benefit in the real-world is still unclear. METHODS: We investigated 1181 Korean patients with programmed death-1 ligand 1 (PD-L1)-positive [tumor proportion score (TPS) ≥ 10% by the SP263 assay or ≥ 50% by the 22C3 assay] R/M-NSCLC treated with pembrolizumab or nivolumab after failure of platinum-based chemotherapy. RESULTS: The median age was 67 years, 13% of patients had ECOG-PS ≥ 2, and 27% were never-smokers. Adenocarcinoma was predominant (61%) and 18.1% harbored an EGFR activating mutation or ALK rearrangement. Pembrolizumab and nivolumab were administered to 51.3% and 48.7, respectively, and 42% received them beyond the third-line chemotherapy. Objective response rate (ORR) was 28.6%. Pembrolizumab group showed numerically higher ORR (30.7%) than the nivolumab group (26.4%), but it was comparable with that of the nivolumab group having PD-L1 TPS ≥ 50% (32.4%). Median progression-free survival (PFS) and overall survival (OS) were 2.9 (95% CI 0-27.9) and 10.7 months (95% CI 0-28.2), respectively. In multivariable analysis, concordance of TPS ≥ 50% in both PD-L1 assays and the development of immune-related adverse events (irAEs) were two significant predictors of better ORR, PFS, and OS. EGFR mutation could also predict significantly worse OS outcomes. CONCLUSION: The real-world benefit of later-line anti-PD1 antibodies was comparable to clinical trials in patients with R/M-NSCLC, although patients generally were more heavily pretreated and had poorer ECOG-PS. Concordantly high PD-L1 TPS ≥ 50% and development of irAE could independently predict better treatment outcomes, while EGFR mutation negatively affected OS.

Prognostic value of E-cadherin expression in non-small cell lung cancer treated with gefitinib.

E-cadherin expression has been suggested to be related with response to EGFR-TK inhibitors. To evaluate the prognostic value of E-cadherin expression in lung cancer treated with gefitinib, we retrospectively reviewed patients with inoperable stage IIIb or IV non-small cell lung cancer treated with gefitinib and compared immunohistochemical staining for E-cadherin on biopsied specimens. The association between gefitinib sensitivity and E-cadherin expression by Western blot and immunocytochemistry was also examined in 10 lung cancer cell lines. Of 52 eligible patients, 15 (28.8%) showed a partial response, and the disease control rate was 42.3%. Median progression-free survival (PFS) and overall survival (OS) in responders were 8 and 20 months, respectively. Response rates (RR), PFS, and disease control rates were higher in never-smokers and patients showing adenocarcinoma histology, and improved OS was observed in patients with adenocarcinoma. E-cadherin expression did not impact any parameters (RR, PFS, or OS). Although there was a tendency for cell lines with lower IC50 to have E-cadherin expression, H2009 cells were the least sensitive to gefitinib, with an IC50 of 30 microM, and H1650 cells had an intermediate sensitivity despite high E-cadherin expression. E-cadherin expression was not a useful indicator of response and survival after treatment with gefitinib.

Radiation Induces Autophagy via Histone H4 Lysine 20 Trimethylation in Non-small Cell Lung Cancer Cells.

BACKGROUND/AIM: Radiotherapy-induced autophagy affects radiation-sensitivity and radiotherapy efficacy. Histone modifications also occur during radiotherapy. This study assessed radiotherapy effects on histone modification and autophagy in non-small cell lung cancer (NSCLC) cells. MATERIALS AND METHODS: NSCLC cells were subjected to γ-irradiation. Autophagy was detected using western blotting and acridine orange staining. Radiation effect on cell growth was evaluated by clonogenic assay. Histone modifications were assessed by western blotting. Next generation sequencings (NGSs) were conducted to identify histone modification target genes. RESULTS: Radio-protective autophagy and histone H4 lysine 20 trimethylation (H4K20me3) were up-regulated after irradiation. By NGSs, genes that are differentially expressed upon irradiation were identified, including the candidate H4K20me3 target gene GABARAPL1. Furthermore, we showed that GABARAPL1 is essential for the radiation-induced autophagy. CONCLUSION: Our findings revealed the regulatory axis of radiation-induced H4K20me3-GABARAPL1 in radio-protective autophagy. Modulation of this axis may be a new strategy to enhance radiotherapy efficacy in NSCLC.

Real-world use of osimertinib in non-small cell lung cancer: ASTRIS study Korean subgroup analysis.

Objective: ASTRIS is a large real-world, open-label, multinational clinical study of osimertinib in patients with epidermal growth factor receptor (EGFR) T790M mutation-positive advanced non-small cell lung cancer (NSCLC) who have previously received a tyrosine kinase inhibitor (TKI). We report data from the Korean ASTRIS subgroup.Methods: Adult patients with locally advanced or metastatic NSCLC with a confirmed T790M mutation, WHO performance status of 0-2 and prior EGFR-TKI therapy, received osimertinib 80 mg once daily. Efficacy outcomes were overall survival (OS), investigator-assessed response rate (RR) and progression-free survival (PFS), and time to treatment discontinuation (TTD).Results: At data cut-off (20 October 2017), 466 Korean patients were enrolled. Baseline EGFR molecular testing was mainly performed on biopsied tissue (75.1%). Baseline mutations co-occurring with T790M included exon 19 deletions (60.7%) and L858R (32.8%). 1-year OS was 82.7% (OS data not matured at data cut-off). Overall, RR was 71.0%, median PFS was 12.4 months and median TTD was 15.0 months. In patients with/without CNS metastases, RR was 68.0% and 79.6%, respectively; median PFS, 10.8 and 11.0 months, respectively; and median TTD, 11.2 and 14.7 months, respectively. Overall, 31.1% of patients experienced ≥1 adverse event (AE), leading to dose modification (12.0%), discontinuation (5.2%) or death (2.8%). Serious AEs (24.9%) included pulmonary embolism (1.7%), pleural effusion (1.7%), and pneumonia (1.5%).Conclusion: In this real-world subgroup analysis of Korean patients in the ASTRIS study, osimertinib demonstrated comparable clinical efficacy to that attained in the global ASTRIS study and other clinical trials, with no new safety concerns.

Epithelial to mesenchymal transition derived from repeated exposure to gefitinib determines the sensitivity to EGFR inhibitors in A549, a non-small cell lung cancer cell line.

Epithelial to mesenchymal transition (EMT) has been reported to be related with reduced sensitivity to EGFR tyrosine kinase (EGFR-TK) inhibitors. We performed this study to investigate whether this phenomenon would play a role in acquired resistance to gefitinib. In this study, we established a gefitinib-resistant subline (A549/GR), which was derived from the parental A549 cell line by chronic, repeated exposure to gefitinib. Compared with the A549 cells, the A549/GR cells were approximately 7.7-fold more resistant to gefitinib and they showed the cross-resistance against other EGFR-TK inhibitors, including CL-387,758, erlotinib and ZD6478. Phenotypic changes such as a spindle-cell shape and increased pseudopodia formation suggesting EMT was present in the A549/GR cells. These changes were accompanied by a decrease of E-cadherin and an increase of vimentin, which is a mesenchymal marker. In addition, the ability of invasion and migration was increased in the A549/GR cells. TGF-beta1 treatment for 72 h also induced EMT in the A549 cells and this transition led to resistance to gefitinib. Conversely, this was reversed through the removal of TGF-beta1. In conclusion, induction of EMT may contribute to the decreased efficacy of therapy in primary and acquired resistance to gefitinib.

Treatment of stage I non-small cell lung cancer with CyberKnife, image-guided robotic stereotactic radiosurgery.

The object of our study was to evaluate the clinical characteristics and outcomes of patients with stage I non-small cell lung cancer (NSCLC) who underwent radiosurgery using the CyberKnife, a newly developed technology to deliver radiation from multiple angles with a real-time target tracking system. A retrospective analysis of eight patients with stage I NSCLC who were treated with curative intent using the CyberKnife between 2002 and 2007 at a cancer center in Korea was performed. Among eight patients (seven men and one woman), three patients were ineligible for surgery due to poor lung function while four patients refused surgical treatment. Tumor size ranged from 19 to 50 mm in the maximal diameter (12 to 113 ml in volume). The administered radiation dose varied from 36 to 54 Gy in three fractions. All of the patients tolerated the treatment very well without any significant side effects. Complete response was achieved and was sustained for almost two years in one male patient until the patient died from a cerebrovascular accident. Seven patients showed radiographic partial response at 1-3 months. Re-growth of tumor at the treated site was observed in only one patient demonstrating an excellent local control rate, although systemic spread or regional lymph node metastasis of disease occurred in six patients during follow-up. CyberKnife treatment is very safe and is able to achieve a high local control rate, suggesting its role as a reasonable alternative therapeutic modality in early lung cancer.

Gefitinib circumvents hypoxia-induced drug resistance by the modulation of HIF-1alpha.

Hypoxia-inducible factor-1alpha (HIF-1alpha) is a transcriptional factor which is activated by hypoxia and associated with cell survival, proliferation and drug resistance. Recent studies have shown that the down-stream molecules of the epidermal growth factor receptor (EGFR) signal are involved in the hypoxia-dependent or -independent HIF-1alpha protein accumulation. Thus, we hypothesized that an EGFR-TK inhibitor, gefitinib, might circumvent the hypoxia-induced drug resistance via the regulation of HIF-1alpha expression. In our data, treatment of gefitinib suppressed induced HIF-1alpha by hypoxia. This action of gefitinib was caused by reduced protein stability without any change in the level of HIF-1alpha mRNA. The effect of gefitinib on down-regulation of HIF-1alpha was reversed by transfection of constitutively active form of Akt. The cellular response to gefitinib was similar in both normoxia and hypoxia condition. However, the response to conventional chemotherapeutic drugs decreased >50% under hypoxia condition and they did not change HIF-1alpha expression. In addition, the suppression of HIF-1alpha using siRNA overcame partially hypoxia-induced drug resistance. In conclusion, gefitinib was able to circumvent hypoxia-induced drug resistance suggesting that the effective suppression of HIF-1alpha by the inhibition of EGFR-Akt pathway may overcome the hypoxia-induced drug resistance.

18F-fluoro-2-deoxy-glucose uptake predicts clinical outcome in patients with gefitinib-treated non-small cell lung cancer.

PURPOSE: To evaluate response and survival according to (18)F-fluoro-2-deoxy-glucose uptake at presentation in patients with gefitinib-treated non-small cell lung cancer. EXPERIMENTAL DESIGN: We retrospectively analyzed 84 positron emission tomography/computed tomography findings. Patient characteristics, response rates, and survivals were evaluated according to the maximum standardized uptake value (SUV) of primary tumor. The cutoff value of SUVs was obtained from receiver operating characteristic analysis. RESULTS: The response rate (RR) was higher for never-smokers (41%) than ever-smokers (9%; P=0.001). Patients with adenocarcinoma showed higher RR than those with other tumor histopathology (35% versus 9%; P=0.009). The SUV was significantly lower in patients who were never-smokers (P=0.005), patients with adenocarcinoma (P<0.001), and female patients (P=0.017). Patients with a low SUV showed higher RR compared with those with a high SUV (53% versus 18%; P=0.003). Prolonged progression-free survival was observed in patients with low SUVs compared with those with high SUVs (median, 33.1 weeks versus 8.6 weeks; P=0.003). While controlling for performance status, smoking history, and pathology, the high SUV conferred unfavorable outcome (hazard ratio, 2.3; P=0.012). In terms of overall survival, a low SUV was associated with favorable outcome in univariate analysis (P=0.011). Patients with a low SUV showed prolonged survival in multivariate analysis (P=0.043). CONCLUSIONS: These results suggest that low SUVs at presentation can predict favorable response and survival in gefitinib-treated non-small cell lung cancer patients.

Therapeutic embolization of systemic arterial supply to normal basal segments of the left lower lobe of the lung.

Systemic arterialization of normal lung without sequestration is a rare congenital abnormality. The basal segments of the left lower lobe are most frequently involved. The involved lung has no structural abnormalities of the tracheobronchial tree that distinguish this abnormality from bronchopulmonary sequestration. Haemoptysis and exertional dyspnoea are common presenting symptoms. We report the case of a 26-year-old man who presented with recurrent haemoptysis due to systemic arterialization of basal segments of the left lower lobe of the lung, without sequestration. Therapeutic embolization using metallic coils was successfully performed without any complications. There was no further haemoptysis during a 6-month follow up. Therapeutic embolization is a safe and effective method of managing the haemoptysis associated with aberrant systemic arterial supply to the normal lung.

p53 enhances gefitinib-induced growth inhibition and apoptosis by regulation of Fas in non-small cell lung cancer.

Treatment with gefitinib, a specific inhibitor of epidermal growth factor receptor tyrosine kinase (EGFR-TK), has resulted in dramatic responses in some patients with non-small cell lung cancer (NSCLC). Most patients who respond to gefitinib have EGFR-TK mutations; however, >10% of patients with EGFR-TK mutations do not respond. Similarly, some patients without EGFR-TK mutations respond to this drug, suggesting that other factors determine sensitivity to gefitinib. Aberrations of the tumor suppressor gene p53 are frequently associated with drug resistance. In this study, we investigated the role of p53 in growth-inhibitory and apoptotic effects of gefitinib in the human NSCLC cell lines NCI-H1299 and A549, which have no EGFR-TK mutations. NCI-H1299 cells, which had a p53-null genotype, were more resistant to gefitinib compared with A549 cells, which were wild-type p53 (IC(50), 40 micromol/L in NCI-H1299 and 5 micromol/L in A549). Treatment of A549 with gefitinib resulted in the translocation of p53 from cytosol to nucleus and the up-regulation of Fas, which was localized to the plasma membrane. In the stable H1299 cell line with tetracycline-inducible p53 expression, induced p53 enhanced growth inhibition and apoptosis by gefitinib through the up-regulation of Fas and restoration of caspase activation. A caspase inhibitor, Z-VAD-fmk, reduced these effects. Conversely, inhibition of p53 using antisense oligonucleotide in A549 caused a significant decrease in apoptosis by gefitinib and down-regulation of Fas under the same conditions. In conclusion, p53 may play a role in determining gefitinib sensitivity by regulating Fas expression in NSCLC.

Factors that Predict Clinical Benefit of EGFR TKI Therapy in Patients with EGFR Wild-Type Lung Adenocarcinoma.

BACKGROUND: Epidermal growth factor receptor (EGFR) mutations in non-small cell lung cancers have emerged as key predictive biomarkers in EGFR tyrosine kinase inhibitor (TKI) treatment. However, a few patients with wild-type EGFR also respond to EGFR TKIs. This study investigated the factors predicting successful EGFR TKI treatment in lung adenocarcinoma patients with wild-type EGFR. METHODS: We examined 66 patients diagnosed with lung adenocarcinoma carrying wide-type EGFR who were treated with EGFR TKIs. The EGFR gene copy number was assessed by silver in situ hybridization (SISH). We evaluated the clinical factors and EGFR gene copy numbers that are associated with a favorable clinical response to EGFR TKIs. RESULTS: The objective response rate was 12.1%, while the disease control rate was 40.9%. EGFR SISH analysis was feasible in 23 cases. Twelve patients tested EGFR SISH-positive, and 11 were EGFR SISH-negative, with no significant difference in tumor response and survival between EGFR SISH-positive and -negative patients. The overall median progression-free survival (PFS) and overall survival (OS) of 66 patients were 2.1 months and 9.7 months, respectively. Female sex and Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 0-1 were independent predictors of PFS. ECOG PS 0-1 and a low tumor burden of extrathoracic metastasis were independent predictors of good OS. CONCLUSION: Factors such as good PS, female sex, and low tumor burden may predict favorable outcomes following EGFR TKI therapy in patients with EGFR wild-type lung adenocarcinoma. However, EGFR gene copy number was not predictive of survival.

Esophageal and laryngeal cancer incidentally found on [18F]fluorodeoxyglucose positron emission tomography/computed tomography during the staging workup for lung cancer.

During staging workup for lung cancer of a 74-year-old man, 2 more incidental tumors were found on [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT). The 3 sites with cancer in this patient involved organs in which field cancerization has often been described, suggesting that triple primary tumors were more probable than metastasis. After treating them separately, complete response was achieved and sustained for > 2 years. The use of FDG-PET/CT seems necessary to evaluate patients with cancer, especially when there is a reasonable chance for cure. Incidentally identified lesions on FDG-PET/CT should be thoroughly explored to rule out the presence of hidden malignancy and the possibility of synchronous multiple primary tumors.

Anti-tumor effect of CDK inhibitors on CDKN2A-defective squamous cell lung cancer cells.

BACKGROUND: Squamous cell lung cancer (SqCLC) is a distinct histologic subtype of non-small cell lung cancer (NSCLC). Although the discovery of driver mutations and their targeted drugs has remarkably improved the treatment outcomes for lung adenocarcinoma, currently no such molecular target is clinically available for SqCLC. The CDKN2A locus at 9p21 encodes two alternatively spliced proteins, p16INK4a (p16) and p14ARF (p14), which function as cell cycle inhibitors. The Cancer Genome Atlas (TCGA) project revealed that CDKN2A is inactivated in 72% of SqCLC cases. In addition, it was found that CDKN2A mutations are significantly more common in SqCLC than in adenocarcinoma. Down-regulation of p16 and p14 by CDKN2A gene inactivation leads to activation of cyclin-dependent kinases (CDKs), thereby permitting constitutive phosphorylation of Rb and subsequent cell cycle progression. Here, we hypothesized that CDK inhibition may serve as an attractive strategy for the treatment of CDKN2A-defective SqCLC. METHODS: We investigated whether the CDK inhibitors flavopiridol and dinaciclib may exhibit antitumor activity in CDKN2A-defective SqCLC cells compared to control cells. The cytotoxic effect of the CDK inhibitors was evaluated using cell viability assays, and the induction of apoptosis was assessed using TUNEL assays and Western blot analyses. Finally, anti-tumor effects of the CDK inhibitors on xenografted cells were investigated in vivo. RESULTS: We found that flavopiridol and dinaciclib induced cytotoxicity by enhancing apoptosis in CDKN2A-defective SqCLC cells, and that epithelial to mesenchymal transition (EMT) decreased and autophagy increased during this process. In addition, we found that autophagy had a cytoprotective role. CONCLUSION: Our data suggest a potential role of CDK inhibitors in managing CDKN2A-defective SqCLC.