Successful Treatment with Crizotinib to Overcome Drug Resistance Possibly Due to Mesenchymal-epithelial Transition Amplification in a Lung Cancer Patient with the Echinoderm Microtubule-associated Protein-like 4-anaplastic Lymphoma Kinase Fusion Gene.

Amplification of the mesenchymal-epithelial transition (MET) gene plays an important role in anticancer drug resistance to anaplastic lymphoma kinase-tyrosine kinase inhibitors (ALK-TKIs) in echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK)-rearranged lung cancer cells. We encountered an ALK-rearranged lung cancer patient who developed MET amplification after alectinib treatment and showed an effective response to fifth-line crizotinib. First-line alectinib treatment was effective for 2.5 years; however, liver metastases exacerbated. Liver biopsy specimens revealed MET and human epidermal growth factor receptor 2 (HER2) amplifications. Switching to the MET inhibitor crizotinib improved liver metastases. Crizotinib may be effective in ALK-positive patients with MET amplification.

Autopsy case of a patient with rapidly progressive combined small-cell lung carcinoma with spindle-shaped cell tumor.

A 69-year-old Japanese man visited our hospital because of worsening shortness of breath. His chest computed tomography (CT) showed a giant left lung mass with a massive left pleural effusion. He could not be treated with chemotherapy and eventually died from a rapidly progressive tumor. He was diagnosed with combined small cell lung carcinoma (C-SCLC) with spindle-shaped cell tumor at autopsy. C-SCLC is characterized by pathologically concurrent SCLC and adenocarcinoma or squamous cell carcinoma, or rarely, spindle-shaped cell tumor. The clinical course of C-SCLC with spindle-shaped cell tumor has not previously been determined. Our patient's tumor increased by 2.59-fold in 20 days. The combination of C-SCLC with spindle-shaped cell tumor suggested rapid progression and a poor prognosis.

Selection of microRNAs in extracellular vesicles for diagnosis of malignant pleural mesothelioma by in vitro analysis.

Malignant pleural mesothelioma (MPM) is a malignant tumor which is a challenge for diagnosis and is associated with a poor patient prognosis. Thus, early diagnostic interventions will improve the quality of life and life expectancy of these patients. Recently, cellular microRNAs (miRNAs) have been found to be involved in maintaining homeostasis, and abnormal miRNA expression has often been observed in various diseases including cancer. Extracellular vesicles (EVs) released by many cells contain proteins and nucleic acids. miRNAs are secreted from all cells via EVs and circulate throughout the body. In this study, culture media were passed sequentially through membrane filters 220­50 nm in size, and EVs with diameters of 50 to 220 nm (EVcap50/220) were collected. miRNAs (EV50­miRNAs) in EVcap50/220 were purified, and microarray analysis was performed. EV50­miRNA expression profiles were compared between MPM cells and a normal pleural mesothelial cell line, and six EV50­miRNAs were selected for further investigation. Of these, hsa­miR­193a­5p and hsa­miR­551b­5p demonstrated higher expression in MPM­derived EVcap50/220. These miRNAs reduced the expression of several genes involved in cell­cell interactions and cell­matrix interactions in normal pleural mesothelial cells. Our data suggest that hsa­miR­193a­5p and hsa­miR­551b­5p in EVcap50/220 could be diagnostic markers for MPM.

Small Cell Lung Cancer Patient with Anti-transcriptional Intermediary Factor 1γ Antibody Who Developed Dermatomyositis after Successful Chemoradiotherapy.

We herein report a 63-year-old woman with small-cell lung cancer (SCLC) who developed dermatomyositis (DM) after initial chemoradiotherapy despite tumor reduction. Serum anti-transcriptional in termediary factor (TIF) 1γ antibody was detected before the development of DM, and its levels increased over time. She died five months after the diagnosis of SCLC. Anti-TIF1γ antibody is known to be a marker for cancer-associated DM (CAM); however, the present case indicates that the antibody can be found in cancer patients without DM. This case is also unusual, as DM developed later despite successful chemoradiotherapy.

Immune-mediated thrombocytopenia and hypothyroidism in a lung cancer patient treated with nivolumab.

Patients treated with immune checkpoint inhibitors can develop various immunological complications; however, few cases of immune thrombocytopenia occurring in association with the administration of these agents have so far been reported. We herein report the case of a 62-year-old Japanese man with non-small-cell lung cancer who developed immune thrombocytopenia and hypothyroidism during nivolumab therapy. After the second administration of the drug, his peripheral blood platelet count rapidly decreased to 1.6 × 104/µl with a petechial rash and symptoms associated with a low thyroid function. Nivolumab-induced immune thrombocytopenia and hypothyroidism were suspected based on the presence of platelet-associated IgG, an increased level of autoantibodies to thyroglobulin and thyroid peroxidase and an enlarged thyroid gland. The patient eventually made a full recovery after treatment with oral prednisolone and levothyroxine. Further investigations and the accumulation of data are necessary to elucidate the precise mechanisms underlying the autoimmune responses that occur in patients treated with immune checkpoint inhibitors.

LSD1/KDM1 isoform LSD1+8a contributes to neural differentiation in small cell lung cancer.

Small cell lung cancer (SCLC) is an aggressive neuroendocrine tumor characterized by rapid progression. The mechanisms that lead to a shift from initial therapeutic sensitivity to ultimate therapeutic resistance are poorly understood. Although the SCLC genomic landscape led to the discovery of promising agents targeting genetic alterations that were already under investigation, results have been disappointing. Achievements in targeted therapeutics have not been observed for over 30 years. Therefore, the underlying disease biology and novel targets urgently require a better understanding. Epigenetic regulation is deeply involved in the cellular plasticity that could shift tumor cells to the malignant phenotype. We have focused on a histone modifier, LSD1, that is overexpressed in SCLC and is a potent therapeutic target. Interestingly, the LSD1 splice variant LSD1+8a, the expression of which has been reported to be restricted to neural tissue, was detected and was involved in the expression of neuroendocrine marker genes in SCLC cell lines. Cells with high expression of LSD1+8a were resistant to CDDP and LSD1 inhibitor. Moreover, suppression of LSD1+8a inhibited cell proliferation, indicating that LSD1+8a could play a critical role in SCLC. These findings suggest that LSD1+8a should be considered a novel therapeutic target in SCLC.