Mediastinal Germ Cell Tumor Exhibiting a Discrepancy between Tumor Markers and Imaging: A Case Study

We report a mediastinal germ cell tumor (GCT) that exhibited a discrepancy between the time course of serum human chorionic gonadotropin (hCG) levels and clinical consequences. An otherwise healthy man, aged 34 years, was diagnosed with a nonseminomatous GCT, most likely embryonal carcinoma (EC), based on a mediastinal tumor biopsy. Standard chemotherapy resulted in an optimal decrease in serum hCG levels. However, multiple lesions in the liver continued to enlarge, which led to his death. Autopsy revealed few viable tumor cells in the liver, with the great majority of the tumor cells appearing to have undergone necrosis, suggesting that they responded to the chemotherapy. The residual tumor cells in the mediastinum and the liver were similar to syncytiotrophoblast cells, suggesting a cho-riocarcinoma (CC). On immunohistochemical analysis, the mediastinal tumor cells in the diagnostic biopsy specimen expressed both CD30 and hCG, whereas residual mediastinal and hepatic tumor cells in the autopsy specimen after chemotherapy also expressed hCG, but not CD30. These findings suggested that the patient suffered from a primary mixed GCT consisting of an EC and a CC. Both pre- and postchemotherapy tumors strongly expressed matrix metalloproteinase-2, supporting the aggressive and invasive features of the tumor phenotype. We speculate that the extremely invasive tumor destroyed normal liver structure, whereas chemotherapy and central necrosis reduced the number of viable cells themselves, causing a discordant decrease in serum hCG levels.Key Words: Nonseminomatous germ cell tumor, Serum human chorionic gonadotropin, Liver metastasis, Matrix metalloproteinase-2     

Minocycline suppresses experimental autoimmune encephalomyelitis by increasing tissue inhibitors of metalloproteinases

Matrix metalloproteinases (MMPs) that are secreted by activated T cells play a significant role in degradation of the extracellular matrix around the blood vessels and facilitate autoimmune neuroinflammation; however, it remains unclear how MMPs act in lesion formation and whether MMP‐targeted therapies are effective in disease suppression. In the present study, we attempted to treat experimental autoimmune encephalomyelitis (EAE) by administration of small interfering RNAs (siRNAs) for MMP‐2, MMP‐9, and minocycline, all of which have MMP‐inhibiting functions. Minocycline, but not siRNAs, significantly suppressed disease development. In situ zymography revealed that gelatinase activities were almost completely suppressed in the spinal cords of minocycline‐treated animals, while significant gelatinase activities were measured in the EAE lesions of control animals. However, MMP‐2 and MMP‐9 mRNAs and proteins in the spinal cords of treated rats were unexpectedly upregulated. At the same time, mRNA for tissue inhibitors of MMPs (TIMP)‐1 and ‐2 were also upregulated. The EnzChek Gelatinase/Collagenase assay using tissue containing native MMPs and TIMPs demonstrated that gelatinase activity levels in the spinal cords of treated rats were suppressed to the same level as those in normal spinal cord tissues. Finally, double immunofluorescent staining demonstrated that MMP‐9 immunoreactivities of treated rats were almost the same as those of control rats and that MMP‐9 and TIMP‐1 immunoreactivities were colocalized in the spinal cord. These findings suggest that minocycline administration does not suppress MMPs at mRNA and protein levels but that it suppresses gelatinase activities by upregulating TIMPs. Thus, MMP‐targeted therapies should be designed after the mechanisms of candidate drugs have been considered.     

Effects of life away from home and physical exercise on nutrient intake and blood/serum parameters among girl students in Japan

This study was initiated to examine if the life away from home and participation in sport activities affect nutritional health among girl university students. For this purpose, anthropometric data, peripheral blood and spot urine samples, 24-hour food duplicate samples, and answers to questionnaires were collected from 71 girl students at 19 to 23 years of ages who provided informed consent to participate in the study. Of the 71 participants, 29 and 42 participants lived in their homes or outside, respectively, and 23 subjects participated in sport activities whereas 48 subjects did not. Hematology, serum biochemistry and nutrient intakes were evaluated in comparison with the life conditions (home vs. dormitory, boarding house, etc.) and participation in sport activities. The population studied had insufficient intake of energy, protein, and minerals such as Ca and Fe. Those who lived in home or participated in sport activities took more energy and protein (although not the two minerals) than others. Skipping of breakfast was more common among those who lived away from home and had no sport activity. Thus, two social factors of life in home and participation in sport clubs contribute favorably for better food habits, but not necessarily improved intakes of Ca and Fe.     

Cellular senescence and the tumour microenvironment

The senescence‐associated secretory phenotype (SASP), where senescent cells produce a variety of secreted proteins including inflammatory cytokines, chemokines, matrix remodelling factors, growth factors and so on, plays pivotal but varying roles in the tumour microenvironment. The effects of SASP on the surrounding microenvironment depend on the cell type and process of cellular senescence induction, which is often associated with innate immunity. Via SASP‐mediated paracrine effects, senescent cells can remodel the surrounding tissues by modulating the character of adjacent cells, such as stromal, immune cells, as well as cancer cells. The SASP is associated with both tumour‐suppressive and tumour‐promoting effects, as observed in senescence surveillance effects (tumour‐suppressive) and suppression of anti‐tumour immunity in most senescent cancer‐associated fibroblasts and senescent T cells (tumour‐promoting). In this review, we discuss the features and roles of senescent cells in tumour microenvironment with emphasis on their context‐dependency that determines whether they promote or suppress cancer development. Potential usage of recently developed drugs that suppress the SASP (senomorphics) or selectively kill senescence cells (senolytics) in cancer therapy are also discussed.     

Proteomics-based identification of alpha-enolase as a tumor antigen in non-small lung cancer

Autoantibodies against tumor antigens represent one type of biomarker that may be assayed in serum for detection of cancer and monitoring of disease progression. In the present study, we used a proteomics-based approach to identify novel tumor antigens in non-small cell lung cancer (NSCLC). By combining two-dimensional electrophoresis, western blotting, mass spectrometry and enzyme-linked immunosorbent assay technology, we detected autoantibodies against alpha-enolase in a subset of NSCLC patients' sera. When 'Mean OD(healthy control sera) + 3 SD(healthy control sera)' was used as the cut-off point, the prevalence of this autoantibody was 27.7% in patients with NSCLC (26 of 94), 1.7% in healthy control subjects (1 of 60), and not detectable in sera from 15 patients with small cell lung cancer, 18 patients with gastrointestinal cancer and nine patients with Mycobacterium avium complex infection of lung. Immunohistochemical staining showed that expression of alpha-enolase was increased in cancer tissues of NSCLC patients, and flow cytometric analysis confirmed the expression of alpha-enolase at the surface of cancer cells. The combined detection of autoantibodies against alpha-enolase, carcinoembryonic antigen and cytokeratin 19 fragment (CYFRA21-1) enhanced sensitivity for the diagnosis of NSCLC. Therefore, autoantibodies against alpha-enolase may constitute a promising biomarker for NSCLC.     

Evaluation of repair activity by quantification of ribonucleotides in the genome

Ribonucleotides incorporated in the genome are a source of endogenous DNA damage and also serve as signals for repair. Although recent advances of ribonucleotide detection by sequencing, the balance between incorporation and repair of ribonucleotides has not been elucidated. Here, we describe a competitive sequencing method, Ribonucleotide Scanning Quantification sequencing (RiSQ-seq), which enables absolute quantification of misincorporated ribonucleotides throughout the genome by background normalization and standard adjustment within a single sample. RiSQ-seq analysis of cells harboring wild-type DNA polymerases revealed that ribonucleotides were incorporated nonuniformly in the genome with a 3′-shifted distribution and preference for GC sequences. Although ribonucleotide profiles in wild-type and repair-deficient mutant strains showed a similar pattern, direct comparison of distinct ribonucleotide levels in the strains by RiSQ-seq enabled evaluation of ribonucleotide excision repair activity at base resolution and revealed the strand bias of repair. The distinct preferences of ribonucleotide incorporation and repair create vulnerable regions associated with indel hotspots, suggesting that repair at sites of ribonucleotide misincorporation serves to maintain genome integrity and that RiSQ-seq can provide an estimate of indel risk.     

Ketoacidosis,Hypertriglyceridemia and Acute Pancreatitis Induced by Soft Drink Polydipsia in a Patient with Occult Central Diabetes Insipidus

A 21-year-old Japanese man without known diabetes mellitus had abdominal pain. The diagnosis was ketoacidosis and hypertriglyceridemia-induced acute pancreatitis. He had polydipsia and polyuria and had habitually drunk several soft drinks every day for two years. After hospitalization, despite adequate liquid intake, dehydration remained with hypotonic polyuria. Further examinations revealed the coexistence of central diabetes insipidus (CDI), possibly caused by lymphocytic infundibulo-neurohypophysitis, based on anti-rabphilin-3A antibody positivity. Although CDI had been undiagnosed for two years, over-consumption of sugar-rich soft drinks to ease thirst caused ketoacidosis, hypertriglyceridemia, and acute pancreatitis. There are no previous reports of this three-part combination of symptoms caused by CDI.     

Non–clinical efficacy,safety and stable clinical cell processing of induced pluripotent stem cell‐derived anti–glypican‐3 chimeric antigen receptor‐expressing natural killer/innate lymphoid cells

The use of allogeneic, pluripotent stem‐cell‐derived immune cells for cancer immunotherapy has been the subject of recent clinical trials. In Japan, investigator‐initiated clinical trials will soon begin for ovarian cancer treatment using human leukocyte antigen (HLA)‐homozygous‐induced pluripotent stem cell (iPSC)‐derived anti–glypican‐3 (GPC3) chimeric antigen receptor (CAR)‐expressing natural killer/innate lymphoid cells (NK/ILC). Using pluripotent stem cells as the source for allogeneic immune cells facilitates stringent quality control of the final product, in terms of efficacy, safety and producibility. In this paper, we describe our methods for the stable, feeder‐free production of CAR‐expressing NK/ILC cells from CAR‐transduced iPSC with clinically relevant scale and materials. The average number of cells that could be differentiated from 1.8‐3.6 × 10⁶ iPSC within 7 weeks was 1.8‐4.0 × 10⁹. These cells showed stable CD45/CD7/CAR expression, effector functions of cytotoxicity and interferon gamma (IFN‐γ) production against GPC3‐expressing tumor cells. When the CAR‐NK/ILC cells were injected into a GPC3‐positive, ovarian‐tumor‐bearing, immunodeficient mouse model, we observed a significant therapeutic effect that prolonged the survival of the animals. When the cells were injected into immunodeficient mice during non–clinical safety tests, no acute systemic toxicity or tumorigenicity of the final product or residual iPSC was observed. In addition, our test results for the CAR‐NK/ILC cells generated with clinical manufacturing standards are encouraging, and these methods should accelerate the development of allogeneic pluripotent stem cell‐based immune cell cancer therapies.     

PAX5 alterations in an infant case of KMT2A‐rearranged leukemia with lineage switch

Lineage switch is a rare event at leukemic relapse. While mostly known to occur in KMT2A‐rearranged infant leukemia, the underlying mechanism is yet to be depicted. This case report describes a female infant who achieved remission of KMT2A‐MLLT3‐rearranged acute monocytic leukemia, but 6 months thereafter, relapsed as KMT2A‐MLLT3‐rearranged acute lymphocytic leukemia. Whole exome sequencing of the bone marrow obtained pre‐post lineage switch revealed two somatic mutations of PAX5 in the relapse sample. These two PAX5 alterations were suggested to be loss of function, thus to have played the driver role in the lineage switch from acute monocytic leukemia to acute lymphocytic leukemia.