Yoshiaki Nagai

Genetic Heterogeneity of the Epidermal Growth Factor Receptor in Non–Small Cell Lung Cancer Cell Lines Revealed by a Rapid and Sensitive Detection System, the Peptide Nucleic Acid-Locked Nucleic Acid PCR Clamp

Lung cancer is one of the leading causes of the cancer death worldwide. Gefitinib is an inhibitor of the tyrosine kinase activity of the epidermal growth factor receptor (EGFR) and has been introduced in the treatment of advanced lung cancers. The responsiveness to gefitinib has been linked to the presence of EGFR mutations. Clinical samples contain many normal cells in addition to cancer cells. A method capable of detecting EGFR mutations in a large background of wild-type EGFR genes could provide a superior clinical test. We developed a rapid and sensitive detection system for EGFR mutations named the peptide nucleic acid-locked nucleic acid (PNA-LNA) PCR clamp that can detect EGFR mutations in the presence of 100-to 1,000-fold background of wild-type EGFR. We used this method to screen 30 non-small cell lung cancer cell lines established from Japanese patients. In addition to 11 cell lines that have mutations, we found 12 cell lines in which specific mutations are observed only in the subpopulation(s) of the cells. Genetic heterogeneity of EGFR suggests that the EGFR gene is unstable in established cancers and the heterogeneity may explain variable clinical responses of lung cancers to gefitinib.

Frequency of and variables associated with the EGFR mutation and its subtypes.

Mutation in the epidermal growth factor receptor (EGFR) is frequently seen in non‐small cell lung cancers (NSCLCs), especially in Asian females with adenocarcinoma. The frequency of mutation and the factors associated requires to be elucidated by analyzing a large number of consecutive clinical samples. We summarized the result of the EGFR mutation analysis for 1,176 patients performed at the time of diagnosis or relapse. The PNA‐LNA PCR clamp, a highly sensitive detection method for the EGFR mutation, was employed. For fresh cases a portion of samples isolated to establish the diagnosis of lung cancer was used. For cases with a relapsed disease archival tissue were tested. The variables associated with the EGFR mutation after removing the confound factors were investigated by the logistic analysis using the samples collected in our university (n = 308) where detailed information on patients were available. The frequency of the EGFR mutation and its subtypes were investigated using all samples (n = 1,176). The EGFR mutation was significantly associated with adenocarcinoma (p = 0.006) and light‐smoking (p < 0.0001), but not gender. The deletions in exon 19 were more frequently associated with male gender while exon 21 deletions were with female gender (p = 0.0011). The overall frequency of the EGFR mutation was 31%. Our result suggests that the female predominance in the EGFR mutation rate is a reflection of a higher frequency of adenocarcinoma in females. The gender difference in the mutation subtypes may provide a clue for the mechanism of the occurrence of the EGFR mutation.

Reliability of the peptide nucleic acid‐locked nucleic acid polymerase chain reaction clamp‐based test for epidermal growth factor receptor mutations integrated into the clinical practice for non‐small cell lung cancers

Gefitinib is an inhibitor of the tyrosine kinase activity of epidermal growth factor receptor (EGFR). Accumulating evidence suggests that gefitinib may provide a survival benefit to EGFR mutation‐positive non‐small lung cancer patients. We have established a clinical test that can detect EGFR mutations from cytological specimens or paraffin‐embedded tissue specimens that are contaminated by normal cells. This test is based on the peptide nucleic acid, locked nucleic acid polymerase chain reaction clamp method that can detect G719S, G719C, L858R, L861Q and seven different exon 19 deletions in the presence of 100–1000‐fold wild‐type alleles. Consequently, using a small aliquot of samples isolated to establish a cancer diagnosis, the EGFR mutation status is determined soon after the diagnosis of cancer is made. We investigated the EGFR mutation status in 86 patients using a variety of cytological specimens (59 bronchoscopy specimens, 16 pleural effusion, 9 sputum, and 2 pericardial effusion) and in 46 patients who had a disease relapse and paraffin‐embedded tissues were available. Forty‐five patients (34%) were positive for mutation (29 exon 19 deletions, 16 L858R and 1 L861Q). The sensitivity and the specificity of this test was 97% and 100%, respectively. EGFR mutation status thereby obtained was used to determine each patients therapeutic regimen. This test is easily integrated into the normal clinical practice for lung cancer, while allowing the medical staff to select therapeutic regimen depending on the EGFR mutation status. (Cancer Sci 2007; 98: 246–252)

Peptide nucleic acid-locked nucleic acid polymerase chain reaction clamp-based detection test for gefitinib-refractory T790M epidermal growth factor receptor mutation

Mutations in the epidermal growth factor receptor (EGFR) are observed in a fraction of non‐small‐cell lung cancers (NSCLS). EGFR mutation‐positive NSCLS responds to gefitinib. Secondary T790M mutation confers gefitinib resistance to NSCLS. A detection test for the T790M mutation was designed based on the peptide nucleic acid–locked nucleic acid polymerase chain reaction clamp method. The specificity and sensitivity of the test were both greater than 0.99. The test revealed that only a small population of the PC‐13 cells carried the T790M mutation. The test also revealed that the T790M mutation was found in none of 151 NSCLC specimens obtained before gefitinib treatment, whereas it was found in four of four specimens obtained from NSCLS that had become refractory to gefitinib. In one patient in whom the L858R‐positive EGFR allele was amplified to multiple copies, an L858R‐T790M double‐mutant allele emerged during the gefitinib therapy. This allele was expressed highly. The T790M mutation detection test based on the peptide nucleic acid–locked nucleic acid polymerase chain reaction clamp method is sensitive and specific, and is applicable to clinical practice. It detects T790M‐positive cells in the course of gefitinib treatment, and thus will help to devise therapies effective for T790M‐positive NSCLS. (Cancer Sci 2008; 99: 595–600)

Phase II study of nimustine hydrochloride (ACNU) plus paclitaxel for refractory small cell lung cancer.

PURPOSE Bi-weekly administrations of nimustine hydrochloride (ACNU) plus paclitaxel were evaluated in this phase II study in patients with refractory small cell lung cancer (SCLC). METHODS Patients who had disease progression within 3 months after treatment with irinotecan (CPT-11)-containing regimens were entered. They were treated with every other week administrations of ACNU 50 mg/m(2) plus paclitaxel 110 mg/m(2) on day 1 over 2 weeks. RESULTS Twenty-four patients (20 males and 4 females, median age of 64 years, 17 patients with Eastern Cooperative Oncology Group [ECOG] performance status [PS] 0-1 and 7 patients with PS 2) participated in the trial. Of the 24 refractory patients after CPT-11 containing regimens, 17 patients had been given etoposide plus platinum. There were six partial responses, and an overall response rate of 25% (95% confidence interval, 10-46%) was obtained. The median time to progression and the median survival time after enrollment into this study were 2.8 and 5.8 months, respectively. The median overall survival from the first-line treatment was 19.5 months. The major toxicity was myelosuppression. Grade 4 neutropenia occurred in 13% of patients, and Grade 4 thrombocytopenia was observed in 13% of patients. There was one treatment-related death, attributed to pneumonitis. CONCLUSION Bi-weekly administrations of ACNU plus paclitaxel provided a practical and well-tolerated regimen that was active for CPT-11-refractory SCLC.

Distinct Benefit of Overall Survival between Patients with Non-Small-Cell Lung Cancer Harboring EGFR Exon 19 Deletion and Exon 21 L858R Substitution

Background: Exon 19 deletion (Del19) and exon 21 L858R substitution (L858R), which account for 90% of epidermal growth factor receptor (EGFR) mutations as common mutations, are associated with favorable outcomes with EGFR-tyrosine kinase inhibitors (TKIs) compared with other uncommon EGFR mutations in non-small-cell lung cancer (NSCLC). However, whether there are differences in overall survival (OS) between patients with these common EGFR mutations remains controversial. Methods: The subjects studied were 74 NSCLC patients with common EGFR mutations treated with gefitinib or erlotinib. Using univariate and multivariate analyses, we retrospectively compared the clinicopahological characteristics of patients harboring Del19 with those harboring L858R. Results: Compared with patients harboring L858R, EGFR-TKIs provided a significant OS benefit in patients harboring Del19 (p = 0.024), as well as favorable therapeutic responses (p = 0.045) and progression-free survival (PFS) benefits (p = 0.031). In multivariate analyses, Del19 was independently associated with PFS (p = 0.029) and OS (p = 0.009), whereas no parameters other than pleural dissemination at the initial treatment were associated with EGFR mutation types. Conclusion: Del19 and L858R have distinct prognostic implications and may require individual therapeutic strategies.

Advanced Lung Adenocarcinoma with Nivolumab-associated Dermatomyositis

We herein report a 42-year-old man with advanced lung adenocarcinoma and nivolumab-associated dermatomyositis. Nivolumab, an anticancer drug that is classified as an immune checkpoint inhibitor, often induces immune-related adverse events (irAEs). However, there have so far been no reports regarding nivolumab-associated dermatomyositis. This patient was diagnosed with dermatomyositis due to the presence of proximal muscle weakness with abnormal electromyography and magnetic resonance imaging findings; skin lesions, such as heliotrope rash, shawl sign, and periungual erythema; and an elevated serum aldolase level after nivolumab administration. It is important to consider drug-associated dermatomyositis in the differential diagnosis of patients presenting with skin lesions and muscle weakness after nivolumab treatment.

A highly specific and sensitive massive parallel sequencer-based test for somatic mutations in non-small cell lung cancer

Molecular targeting therapy for non-small cell lung cancer (NSCLC) has clarified the importance of mutation testing when selecting treatment regimens. As a result, multiple-gene mutation tests are urgently needed. We developed a next-generation sequencer (NGS)-based, multi-gene test named the MINtS for investigating driver mutations in both cytological specimens and snap-frozen tissue samples. The MINtS was used to investigate the EGFR, KRAS, BRAF genes from DNA, and the ERBB2, and the ALK, ROS1, and RET fusion genes from RNA. We focused on high specificity and sensitivity (≥0.99) and even included samples with a cancer cell content of 1%. The MINtS enables testing of more than 100 samples in a single run, making it possible to process a large number of samples submitted to a central laboratory, and reducing the cost for a single sample. We investigated 96 cytological samples and 190 surgically resected tissues, both of which are isolated in daily clinical practice. With the cytological samples, we compared the results for the EGFR mutation between the MINtS and the PNA-LNA PCR clamp test, and their results were 99% consistent. In the snap-frozen tissue samples, 188/190 (99%) samples were successfully analyzed for all genes investigated using both DNA and RNA. Then, we used 200 cytological samples that were serially isolated in clinical practice to assess RNA quality. Using our procedure, 196 samples (98%) provided high-quality RNA suitable for analysis with the MINtS. We concluded that the MINtS test system is feasible for analyzing “druggable” genes using cytological samples and snap-frozen tissue samples. The MINtS will fill a needs for patients for whom only cytological specimens are available for genetic testing.

Severe upper gastrointestinal disorders in pembrolizumab-treated non-small cell lung cancer patient: Pembrolizumab induces upper GI disorders

Pembrolizumab is an immune checkpoint inhibitor that induces side effects called “immune‐related adverse events” (irAEs). Various types of organs are affected by irAEs, although reports of upper gastrointestinal disorders are rare. Here, we report a case of extensive inflammatory pathologies in the oesophagus, stomach, duodenum, and jejunum after the administration of pembrolizumab for non‐small cell lung cancer.

A young immunocompetent patient with spontaneous Aspergillus empyema who developed severe eosinophilia

Aspergillus empyema is usually reported as a complication of surgical procedures, and spontaneous cases are quite rare. Here, we describe the case of a 16-year-old man who suddenly developed dyspnea despite previously being healthy. Chest computed tomography showed multiple mass-containing cavity lesions, pneumothorax, and pleural effusion in the left thorax. Within 2 weeks, Aspergillus fumigatus grew from his pleural effusion, thus he was diagnosed with Aspergillus empyema. He also developed severe eosinophilia after admission, and was treated with anti-fungal drugs. Although there are many factors that can cause eosinophilia, we suspect that infection with Aspergillus fumigatus was the major cause of the eosinophilia in this patient. The lack of bronchial symptoms and lesions were not consistent with a diagnosis of allergic bronchopulmonary aspergillosis. As far as we know, this is the first case of spontaneous Aspergillus empyema resulting in severe eosinophilia.