Absence of copy number gain of EGFR: A possible predictive marker of long-term response to afatinib.

Treatment efficacy of epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) is diverse even in non-small cell lung cancer (NSCLC) patients with EGFR activating mutations. Extraordinary long-term responses sustained over 3 years among NSCLC patients treated with afatinib, an EGFR-TKI, have been reported, but how to predict such long survivors has not been clarified. A multi-institutional prospective observational study, based on comprehensive genomic examination performed with next-generation sequencing of circulating tumor DNA (ctDNA), was conducted to identify potential predictive markers of long-term response to afatinib. Twenty-nine patients with advanced stage NSCLC and EGFR driver mutations detected by standard techniques were enrolled in the study. ctDNA from plasma collected before afatinib treatment was analyzed by Guardant360. ctDNA was detected in 25 of the 29 samples. Median progression-free survival was shorter in patients whose tumors had EGFR copy number gain (7.0 vs 23.0 months, p = 0.022). The impact of EGFR copy number on cell proliferation and the antitumor effect of afatinib were evaluated using genome-editing lung cancer cell lines. HCC827 with EGFR amplification was relatively resistant to afatinib at concentrations below 0.5 nM, but genome-edited derivatives of HCC827 with decreased EGFR copy number demonstrated growth inhibition with 0.1 nM afatinib. The absence of EGFR copy number gain detected in ctDNA may be a predictive marker of long-term response to afatinib. Comprehensive genomic analysis could lead to a more accurate prediction of EGFR-TKI efficacy.

ALDH2 polymorphism rs671 is a predictor of PD-1/PD-L1 inhibitor efficacy against thoracic malignancies.

BACKGROUND: Aldehyde dehydrogenase 2 (ALDH2) plays an important role in the endogenous aldehyde detoxification of various types of cells. ALDH2*2, a variant allele of the ALDH2 polymorphism rs671, leads to decreased enzymatic activity. ALDH2*2 may enhance tumor antigen presentation due to aldehyde-induced DNA damage while suppressing peripheral blood T cell counts and T cell activation. METHODS: On the basis of our hypothesis that rs671 affects the sensitivity of immune checkpoint inhibitors (ICIs), we evaluated the effects of rs671 on patients with thoracic malignancies who started ICI therapy in 2016-2019. The cohort consisted of 105 cases, including 64 cases with adenocarcinoma and 30 cases with squamous cell carcinoma, 49 of whom were ALDH2*2 carriers. The first ICI was PD-1/PD-L1 inhibitor (Nivolumab, Pembrolizumab, or Atezolizumab) in all cases. RESULTS: The best response to anti-PD-1/PD-L1 therapy (partial response/stable disease/progressive disease) was 36%/50%/14% in the rs671(-) cases; however, the response was relatively poor in the rs671(+) cases (27%/29%/45%, respectively) (p = 0.002). The hazard ratio (95% confidence interval) of disease progression within the observation period of 6 months for the rs671(+) cases was estimated to be 5.0 (2.5-10) after the adjustment for covariates, including sex, Brinkman index, treatment line, tumor tissue programmed death-ligand 1 positivity rate, tumor tissue EGFR mutation. This association was also maintained in a stratified analysis, suggesting that ALDH2*2 is an independent negative predictive factor for the short-term prognosis of anti-PD-1/PD-L1 therapy. Thus, the progression-free survival (PFS) ratio of the rs671(+) cases decreased rapidly after ICI initiation but was eventually higher than that of the rs671(-) cases (restricted mean survival time in 12 months from 2 to 3 years afterward was 1.3 times that of the rs671(-) cases). Moreover, the highest PFS ratio after 2 years among sub-groups was found in the first-line treatment sub-group of rs671(+) group (40%). CONCLUSIONS: Our study suggests that rs671 may be an accurate and cost-effective predictor of PD-1/PD-L1 inhibitor treatment, in which optimal case selection is an important issue.

A rare case of Trichosporon mycotoxinivorans and Cryptococcus neoformans co-infection in lung.

A 70-year-old woman with liver cirrhosis caused by primary biliary cirrhosis and rheumatoid arthritis was found to have multiple pulmonary nodular shadows in the right middle and lower lung fields on chest radiography. The multiple pulmonary nodules and masses rapidly increased over 2 months. Trichosporon mycotoxinivorans and Cryptococcus neoformans were identified in brushing specimens, bronchial lavage, and transbronchial lung biopsy specimens. The patient was diagnosed as having a co-infection of the lung with T. mycotoxinivorans and C. neoformans, and was treated with fluconazole. Although the pulmonary shadows were under control with treatment, she died 5 months later due to liver failure. We report herein a rare case of co-infection of the lung with T. mycotoxinivorans and C. neoformans.

Dysautonomia associated with immune checkpoint inhibitors.

OBJECTIVE: The purpose of this study is to report the clinical characteristics of dysautonomia associated with immune checkpoint inhibitors (ICIs). METHODS: We reported two patients with autoimmune autonomic ganglionopathy (AAG) occurring as immune-related adverse events (irAEs). We also performed a review of previous case reports presenting dysautonomia during ICI therapy. Moreover, we conducted pharmacovigilance analyses using the US Food and Drug Administration Adverse Events Reporting System (FAERS) to investigate dysautonomia associated with ICI. RESULTS: Two patients in our care developed both AAG and autoimmune encephalitis following ICI therapy for lung cancers. We comprehensively reviewed 13 published cases (M:F = 11:2, mean onset age of 53 years) with ICI-associated dysautonomia including AAG (n = 3) and autonomic neuropathy (n = 10). Of these, ICI monotherapy was performed in seven and combination ICI use in six. In 6 of 13 patients, dysautonomia appeared within one month after the start of ICIs. Orthostatic hypotension was observed in 7 and urinary incontinence or retention in five. All patients except three showed gastrointestinal symptoms. Anti-ganglionic acetylcholine receptor antibodies were undetectable. All but two patients received immune-modulating therapy. Immuno-modulating therapy was effective in three patients with AAG and two patients with autonomic neuropathy, but ineffective in the others. Five patients died, of either the neurological irAE (n = 3) or cancer (n = 2). The pharmacovigilance analyses using FAERS showed that ipilimumab monotherapy and the combination of nivolumab and ipilimumab constituted significant risks for developing dysautonomia, consistent with the review of literature. CONCLUSION: ICIs can cause dysautonomia including AAG, and autonomic neuropathy is a neurological irAE.

Identification and characterization of endo-α-, exo-α-, and exo-ß-D-arabinofuranosidases degrading lipoarabinomannan and arabinogalactan of mycobacteria.

The cell walls of pathogenic and acidophilic bacteria, such as Mycobacterium tuberculosis and Mycobacterium leprae, contain lipoarabinomannan and arabinogalactan. These components are composed of D-arabinose, the enantiomer of the typical L-arabinose found in plants. The unique glycan structures of mycobacteria contribute to their ability to evade mammalian immune responses. In this study, we identified four enzymes (two GH183 endo-D-arabinanases, GH172 exo-α-D-arabinofuranosidase, and GH116 exo-ß-D-arabinofuranosidase) from Microbacterium arabinogalactanolyticum. These enzymes completely degraded the complex D-arabinan core structure of lipoarabinomannan and arabinogalactan in a concerted manner. Furthermore, through biochemical characterization using synthetic substrates and X-ray crystallography, we elucidated the mechanisms of substrate recognition and anomer-retaining hydrolysis for the α- and ß-D-arabinofuranosidic bonds in both endo- and exo-mode reactions. The discovery of these D-arabinan-degrading enzymes, along with the understanding of their structural basis for substrate specificity, provides valuable resources for investigating the intricate glycan architecture of mycobacterial cell wall polysaccharides and their contribution to pathogenicity.

Factors related to the diagnosis of lung cancer by transbronchial biopsy with endobronchial ultrasonography and a guide sheath.

BACKGROUND: Transbronchial biopsy (TBB) with endobronchial ultrasonography and a guide sheath (EBUS-GS) is an effective examination tool for the diagnosis of lung cancer. Factors related to making the diagnosis are still not fully understood. METHODS: A total of 367 patients who underwent EBUS-GS and were diagnosed with lung cancer in Saga University Hospital were investigated retrospectively. Clinical characteristics were compared between 244 patients who were diagnosed with lung cancer and 123 patients who were not diagnosed by TBB with EBUS-GS but were diagnosed by other examinations. RESULTS: Size of target lesion, rate of patients with target lesion size ≥20 mm, presence of the bronchus sign, and detection by EBUS imaging were significantly associated with making the diagnosis (all p < 0.01). In patients whose lesion was detected by EBUS imaging, patients with positive findings within the lesion were significantly more often diagnosed by TBB with EBUS-GS than those with positive findings adjacent to the lesion (p < 0.01). The odds ratio (OR) of patients whose lesion was detected by EBUS imaging (OR [95% confidence interval] 14.5 [8.0-26.4]) tended to be higher compared to the ORs of size of lesion ≥20 mm (3.9 [2.2-6.8]) and the bronchus sign (7.5 [4.6-12.2]). CONCLUSION: Targeted lesion diameter ≥20 mm, bronchus sign, and detection by EBUS imaging, especially within the lesion, are important factors for the diagnosis of lung cancer by TBB with EBUS-GS.

Acute Generalized Exanthematous Pustulosis Caused by Erlotinib in a Patient with Lung Cancer.

Acute generalized exanthematous pustulosis (AGEP) is a rare drug-related adverse skin reaction caused mainly by antibiotics. Erlotinib is an epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) used to treat lung cancer. A 69-year-old woman with primary lung cancer (adenocarcinoma, cT3N1M1b, stage IVB) developed erythema and multiple skin pustules on her abdomen and both thighs after 7 weeks of erlotinib treatment. She also had fever and general fatigue. Histological examination of a skin biopsy specimen showed intraepidermal pustules with neutrophil and eosinophil infiltration. She was diagnosed with erlotinib-induced AGEP. AGEP resolved by erlotinib discontinuation and systemic corticosteroid treatment. The lung cancer progressed when erlotinib was discontinued, so afatinib, a second-generation EGFR-TKI, was administrated without any skin adverse effects. Afatinib successfully decreased the lung cancer, and maintained the disease stable for 1 year. Although acneiform rash was the most common skin adverse event caused by EGFR, AGEP rarely occurred. The present case also demonstrated that it is possible to switch agents, from erlotinib to afatinib, even though they have the same pharmacological effects. Although AGEP is a rare drug-related skin disorder, physicians should be aware that erlotinib may induce AGEP.

A Low Body Mass Index Is Associated with Unsuccessful Treatment in Patients with Mycobacterium avium Complex Pulmonary Disease.

BACKGROUND: A low body mass index (BMI) has been reported to be a poor prognostic factor for Mycobacterium avium complex pulmonary disease (MAC-PD). The purpose of this study was to clarify the clinical features of MAC-PD in cases with a low BMI. METHODS: This retrospective study analyzed the data of patients diagnosed with MAC-PD at Saga University Hospital between 2008 and 2019. The analyzed patient characteristics included age, gender, BMI, symptoms, laboratory data, chest computed tomography findings, and the treatment courses. We also investigated the factors associated with successful treatment. RESULTS: In total, 144 patients were included in this study. The low-BMI group (BMI < 18.5 kg/m2) had a higher incidence of sputum, Mycobacterium intracellurare infection, and cavitary lesions, in addition to lower blood lymphocyte counts, higher neutrophil-lymphocyte ratios, and a lower prognostic nutritional index (PNI) when compared to the preserved-BMI group (BMI ≥ 18.5 kg/m2). Sixty-six of the 144 patients (45.8%) received treatment. Hemosputum, acid-fast bacillus sputum smear positivity, low lymphocyte counts, a low PNI, and unsuccessful treatment (48.5% vs. 24.2%, p < 0.05) were found to be associated with a low BMI. CONCLUSIONS: A low BMI is associated with cavitary lesions, malnutrition, and unsuccessful treatment in MAC-PD.

The role of comprehensive analysis with circulating tumor DNA in advanced non-small cell lung cancer patients considered for osimertinib treatment.

BACKGROUND: EGFR mutations are good predictive markers of efficacy of EGFR tyrosine kinase inhibitors (EGFR-TKI), but whether comprehensive genomic analysis beyond EGFR itself with circulating tumor DNA (ctDNA) adds further predictive or prognostic value has not been clarified. METHODS: Patients with NSCLC who progressed after treatment with EGFR-TKI, and with EGFR T790 M detected by an approved companion diagnostic test (cobas® ), were treated with osimertinib. Plasma samples were collected before and after treatment. Retrospective comprehensive next-generation sequencing (NGS) of ctDNA was performed with Guardant360® . Correlation between relevant mutations in ctDNA prior to treatment and clinical outcomes, as well as mechanisms of acquired resistance, were analyzed. RESULTS: Among 147 patients tested, 57 patients received osimertinib, with an overall response rate (ORR) of 58%. NGS was successful in 54 of 55 available banked plasma samples; EGFR driver mutations were detected in 43 (80%) and T790 M in 32 (59%). The ORR differed significantly depending on the ratio (T790 M allele fraction [AF])/(sum of variant AF) in ctDNA (p = 0.044). The total number of alterations detected in plasma by NGS was higher in early resistance patients (p = 0.025). T790 M was lost in 32% of patients (6 out of 19) after acquired resistance to osimertinib. One patient with RB1 deletion and copy number gains of EGFR, PIK3CA, and MYC in addition to T790 M, showed rapid progression due to suspected small cell transformation. CONCLUSIONS: NGS of ctDNA could be a promising method for predicting osimertinib efficacy in patients with advanced NSCLC harboring EGFR T790 M.

Association of Genetic Polymorphisms With Afatinib-induced Diarrhoea.

BACKGROUND/AIM: Afatinib, a 2nd generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) used in treatment of non-small cell lung cancer (NSCLC), causes diarrhoea in over 90% of patients. The association of genetic background with diarrhoea is poorly understood. PATIENTS AND METHODS: We evaluated the roles of four single nucleotide polymorphisms (SNPs) in ATP binding cassette subfamily B member 1 (ABCB1) and ATP binding cassette subfamily G member 2 (ABCG2) genes-ABCB1 1236 C>T, 2677 G>T/A, and 3435 C>T, and ABCG2 421 C>A-on treatment-induced diarrhoea in 38 patients with NSCLC treated with afatinib. RESULTS: Diarrhoea occurred more frequently in patients with ABCB1 2677 T(A)/T(A) (14/16, 87.5%) than in patients with non-T(A)/T(A) alleles (8/22, 36.4%) (p=0.003). ABCB1 2677 T(A)/T(A) was significantly predictive of diarrhoea (p=0.002) by multivariable regression analysis. CONCLUSION: Afatinib-induced diarrhoea is associated with the SNP ABCB1 2677 T(A)/T(A).

Origin of circulating free DNA in patients with lung cancer.

Liquid biopsy has become widely applied in clinical medicine along with the progress in innovative technologies, such as next generation sequencing, but the origin of circulating tumor DNA (ctDNA) has not yet been precisely established. We reported bimodal peaks of long fragment circulating free DNA (cfDNA) of 5 kb and short fragment cfDNA of 170 bp in patients with advanced lung cancer, and both contained ctDNA. In this paper, we demonstrate that the total amount of cfDNA is higher when patients with lung cancer have extrathoracic metastases, and the amount of long fragment cfDNA is significantly higher in those patients. To investigate the origin of long fragment cfDNA, conditioned media isolated from lung cancer cell lines was fractionated. Long fragment cfDNA was found concomitant with extracellular vesicles (EVs), but short fragment cfDNA was not observed in any fractions. However, in peripheral blood from a metastatic animal model both fragments were detected even with those same lung cancer cell lines. In human plasma samples, long fragment cfDNA was observed in the same fraction as that from conditioned media, and short fragment cfDNA existed in the supernatant after centrifugation at 100,000g. Concentration of ctDNA in the supernatant was two times higher than that in plasma isolated by the conventional procedure. Long fragment cfDNA associated with tumor progression might therefore be released into peripheral blood, and it is possible that the long fragment cfDNA escapes degradation by co-existing with EVs. Examination of the biological characteristics of long fragment cfDNA is a logical subject of further investigation.

Discontinuation due to immune-related adverse events is a possible predictive factor for immune checkpoint inhibitors in patients with non-small cell lung cancer.

BACKGROUND: Immune-related adverse events (irAEs) should be anticipated with treatment by immune checkpoint inhibitors (ICIs). Although the relationship between irAEs and efficacy of ICI has been reported, it has not yet been clarified whether the benefit from ICI outweighs the low frequency of proceeding to subsequent therapies after discontinuation due to irAEs. METHODS: The study comprised 61 patients with non-small cell lung cancer who underwent treatment with ICIs (nivolumab or pembrolizumab monotherapy) at the Saga University Medical School Hospital from December 2015 to January 2018. Therapeutic effect and progression-free survival (PFS) were compared between the irAEs discontinuation group (AEg) and the group with discontinuation due to all causes other than irAEs (Non-AEg). RESULTS: A total of 30% patients(18/61) had therapy discontinued due to irAEs: 22.5% (9/40) with nivolumab and 42.9% (9/21) with pembrolizumab. The response rate was 50.0% in the AEg and 8.1% in the on-AEg (P = 0.001). The median PFS was significantly longer in the AEg (9.3 months; 95% CI 2.1-12.1) than in the non-AEg (1.9 months; 95% CI 0.9-3.6): HR 0.45 (95%CI 0.20-0.89; log-rank test P = 0.026). The prevalence of drug-induced interstitial lung disease (ILD) was 6.1% (3/49) in cases without interstitial pneumonia (IP) as the underlying disease, whereas it was 50% (6/12) in cases with IP (P = 0.001). CONCLUSION: Discontinuation of treatment with ICIs due to irAEs predict a good response to ICIs and favorable outcome since their anti-cancer effects continue even after discontinuation. However, the presence of IP as the underlying disease increases the risk of drug-related ILD onset.

Paraneoplastic Limbic Encephalitis Complicated with Small Cell Lung Cancer at the Time of Recurrence.

Paraneoplastic limbic encephalitis (PLE) is a rare neurologic disorder that can complicate various malignancies, including lung cancer. PLE is most frequently found the initial presentation of lung cancer. In this study, we reported the case of a 74-year-old Japanese woman who developed PLE after partial remission of small cell lung cancer (SCLC) by first-line systemic chemotherapy. Brain magnetic resonance imaging showed no metastatic tumor or cerebrovascular disease. Anti-glutamic acid decarboxylase (GAD) and anti-amphiphysin antibodies were detected in her serum. She was diagnosed as having PLE related to the recurrence of SCLC and received high-dose glucocorticoid, and sequentially systemic chemotherapy with amrubicin. Unfortunately, these treatments did not improve her disease progression and she died 4 months later. Although PLE rarely occurs at the time of SCLC recurrence, physicians should pay attention to PLE onset even after chemotherapy.

Mechanisms of acquired resistance to afatinib clarified with liquid biopsy.

Although mechanisms of acquired resistance to 1st and 3rd generation EGFR-TKI continue to be elucidated, there have been few clinical investigations into the mechanisms of acquired resistance to the 2nd generation EGFR-TKI afatinib. We analyzed data from 20 patients with advanced lung adenocarcinoma who acquired resistance to afatinib, including resistance during EGFR-TKI re-challenge. We examined EGFR T790M and C797S mutations, BRAF V600E mutation, and MET amplification with the MBP-QP method and with droplet digital PCR using ctDNA and re-biopsy samples obtained before and after afatinib treatment. Just before afatinib treatment, 15 of the 20 patients were T790M negative and five were positive. Among the T790M negative patients, 40.0% (6/15) became positive at the time of PD under afatinib. In patients positive for T790M, changes in T790M allele frequency were correlated with afatinib treatment efficacy. C797S was not detected in any patients just before afatinib treatment, but it appeared after treatment in three patients, although with very low allele frequency. Two of these three patients, although positive for both C797S and T790M, achieved PR to osimertinib. However, PFS of these patients was somewhat shorter than that of patients positive for T790M only. BRAF V600E was detected in one patient at PD under afatinib. MET amplification was not detected in this study. T790M is associated with acquired resistance to afatinib, as with 1st generation EGFR-TKI, but with somewhat lower frequency. The influence of C797S on resistance to afatinib is less than that of T790M, but C797S might cause shorter PFS under osimertinib.

Automated DNA extraction using cellulose magnetic beads can improve EGFR point mutation detection with liquid biopsy by efficiently recovering short and long DNA fragments.

The clinical utility of plasma DNA for detecting cancer-specific mutations has rapidly achieved recognition, but reliability has not been established because of relatively low mutation-detection rates compared with those from tissue re-biopsy. To address this shortcoming we examined efficiency, in terms of mutation detection, of an automated DNA extraction system that uses cellulose magnetic beads. A fully automated, highly sensitive point-mutation-detection method, mutation-biased PCR and quenching probe (MBP-QP) system, was used for this study. Plasma DNA was extracted from 61 plasma samples collected from patients with advanced non-small cell lung cancer. Extraction was performed manually with 200 µl plasma (200-M) by using a silica membrane spin column system or an automated system using 200 µl (200-A) or 1000 µl (1000-A) plasma. Median DNA yield quantified by real-time PCR was 4.4, 4.5, and 17.3 ng with the three methods, respectively. Sensitivity for detecting epidermal growth factor receptor (EGFR) L858R point mutation was 36.6%, 58.5%, and 77.5%, and specificity was 93.3%, 100%, and 96.7%, respectively. Concordance rates were 60.6%, 76.1%, and 85.7%. The size distribution of plasma DNA with automated extraction was bimodal with modes at about 170 bp and 5 Kb, and plasma DNA of both sizes included tumor-derived DNA. In this report, we demonstrate that automated DNA extraction using cellulose magnetic beads can improve mutation-detection rates with plasma DNA in association with two overall sizes of DNA fragments recovered by this DNA isolation system. Examining the biological characteristics of these fragments will be the subject of further investigation.

Investigation of appropriate pre-analytical procedure for circulating free DNA from liquid biopsy.

Liquid biopsy with circulating free DNA (cfDNA) is a recommended alternative method of re-biopsy. Quality control with cfDNA is indispensable for precise examinations, and it is desirable to achieve high-quality cfDNA separation. We investigated two issues: the influence of pre-analytical procedures on cfDNA analysis performed as a routine procedure in a standard clinical laboratory, and the extent of deterioration of cfDNA quality due to long-term storage. Comparisons among blood collection tube types, storage temperatures, and periods of blood separation were performed in terms of cfDNA quantification, cfDNA size distribution, and detection of EGFR mutations. Quality of cfDNA was better with collection tubes containing 3.2% sodium citrate than with those containing EDTA 2K, and was maintained with storage at 4° C for up to 72 h after blood collection, equivalent to results with cell-stabilizing blood collection tubes. Analysis of cfDNA stored for 7 years showed that samples with low allele frequency (AF) deteriorated more readily than samples with high AF. Despite the same storage period and extraction method, AF of plasma stored for 7 years was remarkably lower than that of cfDNA. However, deterioration due to long-term plasma storage was overcome by changing the DNA extraction method from a silica membrane spin column to a cellulose magnetic beads system. These results can guide the establishment of standardized pre-analytical procedures for liquid biopsy with cfDNA.

Current Status and Problems of T790M Detection, a Molecular Biomarker of Acquired Resistance to EGFR Tyrosine Kinase Inhibitors, with Liquid Biopsy and Re-biopsy.

BACKGROUND/AIM: The purpose of this study was to consider appropriate application of liquid and re-biopsy through analysis of current status in practice. PATIENTS AND METHODS: We performed a retrospective analysis of 22 patients with epidermal growth factor receptor (EGFR) mutation-positive non-small cell lung cancer who exhibited 1st/2nd generation EGFR-tyrosine kinase inhibitors resistance. The cobas® method was used to detect T790M with re-biopsy and the mutation-biased PCR and quenched probe method was used with liquid biopsy. RESULTS: T790M detection rate was 52% with re-biopsy and 58% with liquid biopsy. The concordance between tissue and plasma was 58%. One patient who was T790M-positive with liquid biopsy showed heterogeneity among metastatic lesions in terms of osimertinib efficacy, as revealed by T790M detection with re-biopsy. CONCLUSION: Liquid biopsy reflects the whole body, whereas re-biopsy is useful for spatial diagnosis. Considering these characteristics, a combination of liquid and re-biopsy contribute to enhanced treatment.

A case of osimertinib-resistant lung adenocarcinoma responded effectively to alternating therapy.

We report a case of initial lung adenocarcinoma in which transformation to small cell lung carcinoma (SCLC) was observed after acquired resistance to the 3rd generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) osimertinib and alternating treatment between chemotherapy and osimertinib was effective. A 61-year-old woman with EGFR mutation positive stage IV lung adenocarcinoma was administered 1st generation EGFR-TKI for 8 months as the first line therapy, then chemotherapy and 2nd generation EGFR-TKI after progressive disease (PD). Four years after initial diagnosis, EGFR T790M was detected in a metastatic lesion of the right thoracic wall and osimertinib was prescribed. Although partial response (PR) was achieved, a new metastatic lesion appeared in the right pleurum near the diaphragm, in which SCLC characteristics were observed with elevation of pro-gastrin-releasing peptide (pro-GRP) at the time of PD under osimertinib. Osimertinib was discontinued and carboplatin plus irinotecan chemotherapy was chosen as the next treatment, leading to PR after 2 cycles. Subsequently, the right thoracic wall tumor harboring T790M and the right pleural tumor near the diaphragm showing transformation to SCLC exhibited opposite responses to therapy alternating between osimertinib and chemotherapy. It is concluded that extended disease control can be achieved by combining appropriate treatments according to the mechanisms of resistance inferred from precise genetic and pathological examination in real time.

Functional analysis of Discoidin domain receptor 2 mutation and expression in squamous cell lung cancer.

OBJECTIVES: Discoidin domain receptor (DDR) 2 mutations have recently been reported to be candidate targets of molecular therapy in lung squamous cell carcinoma (SQCC). However, the status of DDR2 expression and mutations, as well as their precise roles in lung SQCC, have not been clarified. We here report DDR2 mutation and expression status in clinical samples and its role of lung SQCC. MATERIALS AND METHODS: We investigated DDR2 expression and mutation status in 44 human clinical samples and 7 cell lines. Biological functions of DDR2 were assessed by in vitro cell invasion assay and animal model experiments. RESULTS: Endogenous DDR2 protein expression levels were high in one cell line, PC-1, and immunohistochemistry of lung cancer tissue array showed high levels of DDR2 protein in 29% of lung SQCC patients. A mutation (T681I) identified in lung SQCC and the cell line EBC-1 was detected among 44 primary lung SQCC samples and 7 lung SQCC cell lines. Although Forced expression of DDR2 and its mutant (T681I) led to induce SQCC cell invasion in vitro, only wild type DDR2 enhanced lung metastasis in an animal model. We also found that ectopic expression of DDR2 induced MMP-1 mRNA expression accompanied by phosphorylation of c-Jun after treatment with its ligand, collagen type I, but DDR2 with the T681I mutation did not, suggesting that T681I mutation is an inactivating mutation. CONCLUSION: Overexpression of DDR2 might contribute to tumor progression in lung SQCC. The overexpression of DDR2 could be potential molecular target of lung SQCC.