水谷 泰嘉

CERS6 is associated with metastasis and poor prognosis in non-small cell lung cancer (NSCLC) patients through d18:1/C16:0 ceramide (C16 ceramide)-mediated cell migration, though the detailed mechanism has not been elucidated. In the present study, examinations including co-immunoprecipitation, liquid chromatography, and tandem mass spectrometry analysis were performed to identify a novel binding partner of CERS6. Among the examined candidates, LASP1 was a top-ranked binding partner, with the LIM domain possibly required for direct interaction. In accord with those findings, CERS6 and LASP1 were found to co-localize on lamellipodia in several lung cancer cell lines. Furthermore, silencing of CERS6 and/or LASP1 significantly suppressed cell migration and lamellipodia formation, whereas ectopic addition of C16 ceramide partially rescued those phenotypes. Both LASP1 and CERS6 showed co-immunoprecipitation with actin, with those interactions markedly reduced when the LASP1–CERS6 complex was abolished. Based on these findings, it is proposed that LASP1–CERS6 interaction promotes cancer cell migration.

The enzyme-labeled antigen method is an immunohistochemical technique detecting plasma cells producing specific antibodies in tissue sections. The probe is an antigen labeled with an enzyme or biotin. This immunohistochemical technique is appliable to frozen sections of paraformaldehyde (PFA)-fixed tissues, but it has been difficult to apply it to formalin-fixed, paraffin-embedded (FFPE) sections. In the current study, factors inactivating the antibody reactivity during the process of preparing FFPE sections were investigated. Lymph nodes of rats immunized with horseradish peroxidase (HRP) or a mixture of keyhole limpet hemocyanin/ovalbumin/bovine serum albumin were employed as experimental models. Plasma cells producing specific antibodies, visualized with HRP (as an antigen with enzymatic activity) or biotinylated proteins in 4% PFA-fixed frozen sections, significantly decreased in unbuffered 10% formalin-fixed frozen sections. The positive cells were further decreased by paraffin embedding following formalin fixation. In paraffin-embedded sections fixed in precipitating fixatives such as ethanol and acetone and those prepared with the AMeX method, the antigen-binding reactivity of antibodies was preserved. Fixation in periodate-lysine-paraformaldehyde and Zamboni solution also kept the antigen-binding reactivity in paraffin to some extent. In conclusion, formalin fixation and paraffin embedding were major causes inactivating antibodies. Precipitating fixatives could retain the antigen-binding reactivity of antibodies in paraffin-embedded sections.

Ceramide synthase 6 (CERS6) promotes lung cancer metastasis by stimulating cancer cell migration. To examine the underlying mechanisms, we performed luciferase analysis of the CERS6 promoter region and identified the Y-box as a cis-acting element. As a parallel analysis of database records for 149 non-small-cell lung cancer (NSCLC) cancer patients, we screened for trans-acting factors with an expression level showing a correlation with CERS6 expression. Among the candidates noted, silencing of either CCAAT enhancer-binding protein γ (CEBPγ) or Y-box binding protein 1 (YBX1) reduced the CERS6 expression level. Following knockdown, CEBPγ and YBX1 were found to be independently associated with reductions in ceramide-dependent lamellipodia formation as well as migration activity, while only CEBPγ may have induced CERS6 expression through specific binding to the Y-box. The mRNA expression levels of CERS6, CEBPγ, and YBX1 were positively correlated with adenocarcinoma invasiveness. YBX1 expression was observed in all 20 examined clinical lung cancer specimens, while 6 of those showed a staining pattern similar to that of CERS6. The present findings suggest promotion of lung cancer migration by possible involvement of the transcription factors CEBPγ and YBX1.

Sphingolipids constitute a class of bio-reactive molecules that transmit signals and exhibit a variety of physical properties in various cell types, though their functions in cancer pathogenesis have yet to be elucidated. Analyses of gene expression profiles of clinical specimens and a panel of cell lines revealed that the ceramide synthase gene CERS6 was overexpressed in non-small-cell lung cancer (NSCLC) tissues, while elevated expression was shown to be associated with poor prognosis and lymph node metastasis. NSCLC profile and in vitro luciferase analysis results suggested that CERS6 overexpression is promoted, at least in part, by reduced miR-101 expression. Under a reduced CERS6 expression condition, the ceramide profile became altered, which was determined to be associated with decreased cell migration and invasion activities in vitro. Furthermore, CERS6 knockdown suppressed RAC1-positive lamellipodia/ruffling formation and attenuated lung metastasis efficiency in mice, while forced expression of CERS6 resulted in an opposite phenotype in examined cell lines. Based on these findings, we consider that ceramide synthesis by CERS6 has important roles in lung cancer migration and metastasis.

Diagnosis of gastric adenocarcinoma using small biopsy samples is occasionally difficult. Various markers have been employed for improving the diagnostic accuracy, but there remains room for improvement. A total of 129 endoscopically biopsied samples were studied, consisting of 104 intramucosal tubular adenocarcinomas, 24 non-cancerous lesions and one cancer sample originally suspected of non-cancer but revised as cancer after immunostaining. We evaluated the association between histopathology and immunohistochemical expression of MUC1, HER2, p53, CEA, E-cadherin, β-catenin and claudin-18. Regarding β-catenin and claudin-18, not only membranous expression (β-catenin(M) and claudin-18(M)) but also nuclear expression (β-catenin(N) and claudin-18(N)) were analyzed. When subtyped with mucin core protein expression, the gastric-type cancers dominantly expressed claudin-18(M), while claudin-18(N) was significantly encountered in intestinal- and mixed-types. Expression of MUC1 (P = 0.0010), HER2 (P = 0.0173), p53 (P = 0.0002), CEA (P = 0.0019) and claudin-18(N) (P < 0.0001) revealed significant correlation with gastric cancers. Negative correlation of claudin-18(M) (P = 0.0125) was also noted. MUC1 and p53 were negative in non-cancer lesions. The non-cancer group exceptionally expressed HER2 and β-catenin(N). Membranous expression of E-cadherin was consistent in both groups. Logistic regression analysis showed that MUC1 (P = 0.0086), p53 (P = 0.0031), claudin-18(M) (P = 0.0158) and claudin-18(N) (P = 0.0190) were independently associated with gastric cancers. Nuclear expression of claudin-18 should be the novel diagnostic marker for gastric cancer.

Neutrophil extracellular traps (NETs) released from dead neutrophils at the site of inflammation represent webs of neutrophilic DNA stretches dotted with granule-derived antimicrobial proteins, including lactoferrin, and play important roles in innate immunity against microbial infection. We have shown the coexistence of NETs and fibrin meshwork in varied fibrinopurulent inflammatory lesions at both light and electron microscopic levels. In the present study, correlative light and electron microscopy (CLEM) employing confocal laser scanning microscopy and scanning electron microscopy was performed to bridge light and electron microscopic images of NETs and fibrin fibrils in formalin-fixed, paraffin-embedded, autopsied lung sections of legionnaire's pneumonia. Lactoferrin immunoreactivity and 4'-6-diamidino-2-phenylindole (DAPI) reactivity were used as markers of NETs, and fibrin was probed by fibrinogen gamma chain. Of note is that NETs light microscopically represented as lactoferrin and DAPI-colocalized dots, 2.5 μm in diameter. CLEM gave super-resolution images of NETs and fibrin fibrils: "Dotted" NETs were ultrastructurally composed of fine filaments and masses of 58 nm-sized globular materials. A fibrin fibril consisted of clusters of smooth-surfaced filaments. NETs filaments (26 nm in diameter) were significantly thinner than fibrin filaments (295 nm in diameter). Of note is that CLEM was applicable to formalin-fixed, paraffin-embedded sections of autopsy material.

Neutrophil extracellular traps (NETs) are extracellular fibrillary structures composed of degraded chromatin and granules of neutrophil origin. In fibrinopurulent inflammation such as pneumonia and abscess, deposition of fibrillar eosinophilic material is a common histopathological finding under hematoxylin-eosin staining. Expectedly, not only fibrin fibrils but also NETs consist of the fibrillar material. The aim of the present study is to analyze immunohistochemically how NETs are involved in the inflammatory process. Archival formalin-fixed, paraffin-embedded sections accompanying marked neutrophilic infiltration were the target of analysis. Neutrophil-associated substances (citrullinated histone H3, lactoferrin, myeloperoxidase and neutrophil elastase) were evaluated as NETs markers, while fibrinogen gamma chain was employed as a fibrin marker. Light microscopically, the fibrils were categorized into three types: thin, thick and clustered thick. Lactoferrin represented a good and stable NETs marker. Thin fibrils belonged to NETs. Thick fibrils are composed of either mixed NETs and fibrin or fibrin alone. Clustered thick fibrils were solely composed of fibrin. Neutrophils were entrapped within the fibrilllar meshwork of the thin and thick types. Apoptotic cells immunoreactive to cleaved caspase 3 and cleaved actin were dispersed in the NETs. In conclusion, NETs and fibrin meshwork were consistently recognizable by immunostaining for lactoferrin and fibrinogen gamma chain.

Neutrophil extracellular traps (NETs) represent an extracellular, spider’s web-like structure resulting from cell death of neutrophils. NETs play an important role in innate immunity against microbial infection, but their roles in human pathological processes remain largely unknown. NETs and fibrin meshwork both showing fibrillar structures are observed at the site of fibrinopurulent inflammation, as described in our sister paper [Acta Histochem. Cytochem. 49 109-116, 2016]. In the present study, immunoelectron microscopic study was performed for visualizing NETs and fibrin fibrils (thick fibrils in our tongue) in formalin-fixed, paraffin-embedded sections of autopsied lung tissue of legionnaire’s pneumonia. Lactoferrin and fibrinogen gamma chain were utilized as markers of NETs and fibrin, respectively. Analysis of immuno-scanning electron microscopy indicated that NETs constructed thin fibrils and granular materials were attached onto the NETs fibrils. The smooth-surfaced fibrin fibrils were much thicker than the NETs fibrils. Pre-embedding immunoelectron microscopy demonstrated that lactoferrin immunoreactivities were visible as dots on the fibrils, whereas fibrinogen gamma chain immunoreactivities were homogeneously observed throughout the fibrils. Usefulness of immunoelectron microscopic analysis of NETs and fibrin fibrils should be emphasized.

In chronic inflammatory lesions of autoimmune and infectious diseases, plasma cells are frequently observed. Antigens recognized by antibodies produced by the plasma cells mostly remain unclear. A new technique identifying these corresponding antigens may give us a breakthrough for understanding the disease from a pathophysiological viewpoint, simply because the immunocytes are seen within the lesion. We have developed an enzymelabeled antigen method for microscopic identification of the antigen recognized by specific antibodies locally produced in plasma cells in inflammatory lesions. Firstly, target biotinylated antigens were constructed by the wheat germ cell-free protein synthesis system or through chemical biotinylation. Next, proteins reactive to antibodies in tissue extracts were screened and antibody titers were evaluated by the AlphaScreen method. Finally, with the enzymelabeled antigen method using the biotinylated antigens as probes, plasma cells producing specific antibodies were microscopically localized in fixed frozen sections. Our novel approach visualized tissue plasma cells that produced 1) autoantibodies in rheumatoid arthritis, 2) antibodies against major antigens of Porphyromonas gingivalis in periodontitis or radicular cyst, and 3) antibodies against a carbohydrate antigen, Strep A, of Streptococcus pyogenes in recurrent tonsillitis. Evaluation of local specific antibody responses expectedly contributes to clarifying previously unknown processes in inflammatory disorders.

Streptococcus pyogenes is the main causative pathogen of recurrent tonsillitis. Histologically, lesions of recurrent tonsillitis contain numerous plasma cells. Strep A is an antigenic carbohydrate molecule on the cell wall of S. pyogenes. As expected, plasma cells in subjects with recurrent tonsillitis secrete antibodies against Strep A. The enzyme-labeled antigen method is a novel histochemical technique that visualizes specific antibody-producing cells in tissue sections by employing a biotin-labeled antigen as a probe. The purpose of the present study was to visualize plasma cells producing antibodies reactive with Strep A in recurrent tonsillitis. Firstly, the lymph nodes of rats immunized with boiled S. pyogenes were paraformaldehyde-fixed and specific plasma cells localized in frozen sections with biotinylated Strep A. Secondly, an enzyme-labeled antigen method was used on human tonsil surgically removed from 12 patients with recurrent tonsillitis. S. pyogenes genomes were PCR-detected in all 12 specimens. The emm genotypes belonged to emm12 in nine specimens and emm1 in three. Plasma cells producing anti-Strep A antibodies were demonstrated in prefixed frozen sections of rat lymph nodes, 8/12 human specimens from patients with recurrent tonsillitis but not in two control tonsils. In human tonsils, Strep A-reactive plasma cells were observed within the reticular squamous mucosa and just below the mucosa, and the specific antibodies belonged to either IgA or IgG classes. Our technique is effective in visualizing immunocytes producing specific antibodies against the bacterial carbohydrate antigen, and is thus a novel histochemical tool for analyzing immune reactions in infectious disorders.

We established a new "ecological" Grocott stain for demonstrating fungi, based upon a 4R principle of refusal, reduction, reuse, and recycle of waste management. Conventional Grocott stain employs environmentally harsh 5% chromic acid for oxidization. Initially, we succeeded in reducing the concentration of chromic acid from 5% to 1% by incubating the solution at 60 degrees C and using five-fold diluted chromic acid solution at which point it was reusable. Eventually, we reached the refusal level where 1% periodic acid oxidization was efficient enough, when combined with preheating of sections in the electric jar, microwave oven, or pressure pan. For convenience sake, we recommend pressure pan heating in tap water for 10 min. Stainability of fungi in candidiasis and aspergillosis was comparable with conventional Grocott stain, while Mucor hyphae showed enhanced staining. The modified sequence was further applicable to detecting a variety of mycotic pathogens in paraffin sections. Our environmentally-friendly Grocott stain also has the advantage of avoiding risk of human exposure to hexavalent chromium solution in the histopathology laboratory. The simple stain sequence is can be easily applied worldwide.

We performed pre-embedding electron microscopic study for visualizing the antigen and genome of severe fever with thrombocytopenia syndrome (SFTS) virus in the cytoplasm of macrophages of the human splenic red pulp, both requesting preheating treatment of sections. To pursue this, coated glass slides with unique characteristics are needed. Namely, during staining they must prevent detaching off sections, but after staining the sections must be transferred to epoxy resin. Aminopropyltriexoxysilane-coated glass slides, widely used for immunostaining, were resistant to transfer to epoxy resin. In contrast, coated glass slides designated as Thinlayer Advanced Cytology Assay System (TACAS) were suitable for this purpose. The technique is also applicable to the coated glass slide-requiring cytology practice, in which immunocytochemical evaluation is needed after cell transfer to another glass slide.

Porphyromonas gingivalis is a keystone periodontal pathogen. Histologocally, the gingival tissue in periodontitis shows dense infiltration of plasma cells. However, antigens recognized by antibodies secreted from the immunocytes remain unknown. The enzyme-labeled antigen method was applied to detecting plasma cells producing P. gingivalis-specific antibodies in biopsied gingival tissue of periodontitis. N-terminally biotinylated P. gingivalis antigens, Ag53 and four gingipain domains (Arg-pro, Arg-hgp, Lys-pro and Lys-hgp) were prepared by the cell-free protein synthesis system using wheatgerm extract. With these five labeled proteins as probes, 20 lesions of periodontitis were evaluated. With the AlphaScreen method, antibodies against any one of the five P. gingivalis antigens were detected in 11 (55%) serum samples and 17 (85%) tissue extracts. Using the enzyme-labeled antigen method on paraformaldehyde-fixed frozen sections of gingival tissue, plasma cells were labeled with any one of the five antigens in 17 (94%) of 18 specimens, in which evaluable plasma cells were detected. The positivity rates in periodontitis were significantly higher than those found previously in radicular cysts (20% in sera and 33% in tissue extracts with the AlphaScreen method, and 25% with the enzyme-labeled antigen method). Our findings directly indicate that antibodies reactive to P. gingivalis are locally produced in the gingival lesions, and that inflammatory reactions against P. gingivalis are involved in periodontitis. © 2014 The Authors.

Synovial tissue in rheumatoid arthritis (RA) shows dense infiltration of plasmacytes. The purpose of the present study is to identify and localize autoantibodies produced in these immunocytes in RA synovitis. We developed a novel screening system for detecting specific autoantigens. Protein antigens recognized by antibodies in the serum and synovial tissue extract from five RA patients were screened with the AlphaScreen method. For screening, a biotinylated human autoantigen library was constructed by the wheat germ cell-free protein synthesis system. The AlphaScreen analysis of 2183 proteins detected a limited number of antigens reactive with the serum and synovial tissue extract. Eighteen biotinylated proteins, containing top five showing high signals in each synovitis tissue extract, were utilized as probes for the enzyme-labeled antigen method, in order to visualize the site of specific antibody production in synovial lesions. Specific antibodies against two proteins, tripartite motif-containing 21 (TRIM21, also known as SSA/Ro52) and F-box only protein 2 (FBXO2), were visualized in the cytoplasm of plasmacytes in two RA synovitis lesions, respectively. Absorption experiments using unlabeled proteins confirmed the specificity of staining. No positive signals against these two proteins were identified in the additionally evaluated RA and osteoarthritis synovial lesions. The present study indicated 1) the usefulness of screening the human autoantigen library with the AlphaScreen assay for detecting autoantibodies in RA synovitis, and 2) the applicability of biotinylated proteins to the enzyme-labeled antigen method for visualizing the site of autoantibody production within the lesion. © 2012 Elsevier B.V.

<italic>Background</italic>.<italic>In situ</italic>hybridization (ISH) with high sensitivity has been requested to demonstrate hepatitis C virus (HCV) RNA in formalin-fixed, paraffin-embedded (FFPE) sections of the liver.<italic>Methods</italic>. ISH employing a locked-nucleic-acid- (LNA-)modified oligonucleotide probe and biotin-free catalyzed signal amplification system (CSAII) was applied to HCV-RNA detection in the liver tissue. Nested reverse-transcription polymerase chain reaction (RT-PCR) was performed for HCV genotyping using total RNA extracted from FFPE sections. The target tissues included FFPE tissue sections of humanized livers in HCV-infected chimeric mice (HCV genotypes 1a, 1b, and 2a and noninfected) and of needle-biopsied livers from HCV-infected patients.<italic>Results</italic>. HCV-RNA was demonstrated with the ISH technique in HCV-infected liver tissues from both chimeric mice and 9 (82%) of 11 patients with HCV infection. The HCV signals were sensitive to RNase. Nested RT-PCR confirmed the genotype in 8 (73%) of 11 livers (type 1b: 6 lesions and type 2a: 2 lesions). HCV-RNA was not identified in chronic hepatitis B lesions, fatty liver, autoimmune hepatitis, and hepatocellular carcinoma.<italic>Conclusion</italic>. ISH using the LNA-modified oligonucleotide probe and CSAII was applicable to detecting HCV-RNA in routinely prepared FFPE liver specimens.

Japanese spotted fever (JSF) is caused by Rickettsia japonica, and lethal cases are reported yearly in southwest Japan. We thus established the method of diagnosing JSF by immunohistochemistry (IHC) and real-time PCR (RT-PCR) using formalin-fixed, paraffin-embedded skin biopsy specimens. Two monoclonal antibodies were used for IHC, and the 17k genus common antigen gene served as the target of RT-PCR. We collected skin biopsy (n=61) and autopsy (n=1) specimens from 50 patients clinically suspected of JSF. Immunohistochemically, the rickettsial antigens were localized as coarse dots in the cytoplasm of endothelial cells and macrophages. Thirty-one seropositive cases plus one autopsy case (group A) and nine seronegative cases but with positive IHC and/or RT-PCR (group B) were judged as JSF. Nine cases were regarded as non-JSF disorders based on negative serology, IHC and RT-PCR (group C). Of 50 biopsies (eschar 34, eruptions 10, and scabs 6) from groups A and B, IHC and RT-PCR positivities were 94% (32/34) and 62% (21/34) for eschar, 80% (8/10) and 30% (3/10) for eruptions, and 33% (2/6) and 50% (3/6) for scabs. For IHC, eschar was most suitable, and scabs were insufficient. Unexpectedly, 18 biopsies happened to be fixed in 100% formalin, and this lowered the detection rate by RT-PCR, but IHC was tolerant. Sequence analysis using five skin biopsy specimens confirmed a 114bp DNA stretch homologous to that reported for the target gene of R. japonica. In 26 (84%) of the 31 seropositive patients, the diagnosis was made by IHC and/or RT-PCR earlier than serology. © 2011 The Authors. Clinical Microbiology and Infection © 2011 European Society of Clinical Microbiology and Infectious Diseases.

The hepatitis C virus (HCV) outbreak that occurred between 1940 and 1999 in a closed leprosy sanatorium located on a small island in Japan was analyzed. The analysis of 318 nucleotides in the NS5B region of HCV allowed us to establish the existence of at least three different HCV strains in this sanatorium. Copyright © 2011, American Society for Microbiology. All Rights Reserved.

The enzyme-labeled antigen method was applied to visualize plasma cells producing antibodies to Porphyromonas gingivalis, flora of the human oral cavity. Antibodies to P. gingivalis have reportedly been detected in sera of patients with periodontitis. Biotinylated bacterial antigens, Ag53, and four gingipain domains (Arg-pro, Arg-hgp, Lys-pro, and Lys-hgp) were prepared by the cell-free protein synthesis system using the wheat germ extract. In paraformaldehyde-fixed frozen sections of rat lymph nodes experimentally immunized with Ag53-positive and Ag53-negative P. gingivalis, plasma cells were labeled with biotinylated Arg-hgp and Lys-hgp. Antibodies to Ag53 were detected only in the nodes immunized with Ag53-positive bacteria. In two of eight lesions of gingival radicular cyst with inflammatory infiltration, CD138-positive plasma cells in frozen sections were signalized for Arg-hgp and Lys-hgp. An absorption study using unlabeled antigens confirmed the specificity of staining. The AlphaScreen method identified the same-type antibodies in tissue extracts but not in sera. Antibodies to Ag53, Arg-pro, and Lys-pro were undetectable. In two cases, serum antibodies to Arg-hgp and Lys-hgp were AlphaScreen positive, whereas plasma cells were scarcely observed within the lesions. These findings indicate the validity of the enzyme-labeled antigen method. This is the very first application of this novel histochemical technique to human clinical samples. © The Author(s) 2011.

Oku-Komyo-En is one of the national leprosy sanatoria, located on a small island in Setouchi city, Okayama prefecture of Japan since 1938. Since autopsies were carried out routinely on almost all patients who had died in the sanatorium up to 1980, approximately 1,000 formalin-fixed autopsy tissue samples were available for analysis. When these samples were reviewed, the pathological data indicated a sharp rise in the death rate caused by cirrhosis of the liver and hepatocellular carcinoma (HCC) since 1960 and 1970, respectively. Hepatitis C virus (HCV) infection is a common cause of HCC in Japan. The presence of HCV RNA was demonstrated in paraffin sections prepared from the autopsied liver tissue fixed in formalin for a prolonged period of time, by employing nested RT-PCR using type-specific primers. The data showed that HCV RNA was detectable in samples of the liver archived as early as 1940, representing the liver tissues kept in formalin for up to 67 years. HCV genotypes 1b and 2a were found by RT-PCR at 85.7% and 14.3%, respectively, in patients with leprosy. © 2010 Wiley-Liss, Inc.

The enzyme-labeled antigen method is a histochemical technique that visualizes antigen-specific antibody-producing cells in tissue sections, originally documented in 1968. In this study, we attempted to reemerge this hidden but potentially useful method in rat models immunized with horseradish peroxidase (HRP), ovalbumin (OA), or keyhole limpet hemocyanin (KLH). After repeated immunization in footpads, popliteal, groin, and axillary lymph nodes and spleen were sampled. Paraformaldehyde-prefixed frozen sections were incubated with HRP, biotinylated OA, or biotinylated KLH. Proteinase K pretreatment and the secondary use of HPR-labeled streptavidin were applied in the latter two situations. Plasma cells producing antigen-specific antibodies were visualized. Proportions of antigen-specific antibody-producing cells in total plasma cells shown with the immunoperoxidase method for rat immunoglobulins were evaluated. The percentage of antigen-specific plasma cells reached similar to 50% of total plasma cells in the regional lymph nodes. The specificity was confirmed by (a) negativity in non-immune rat tissue, (b) negativity with indifferent antigen probes, and (c) abolishment of the reactivity with the corresponding rat serum. in buffered formalin-fixed, paraffin-embedded tissues, fewer plasma cells were labeled for HRP and KLH antibody reactivity after strong proteolysis and prolonged incubation. Expectedly, this method allows us to observe antigen-specific antibody-producing cells under varied pathological conditions. (J Histochem Cytochem 57:101-111, 2009)

We immunohistochemically evaluated the involvement of five cancer cachexia-related factors, including leukemia-inhibitory factor (LIF), zinc-alpha 2-glycoprotein (ZAG), interleukin 6 (IL-6), proteolysis-inducing factor (PIF) and tumor necrosis factor alpha (TNF alpha) in causing cancer cachexia. Twenty-six xenografts implanted into mice were examined for the expression of the cancer cachexia-related factors, in relation to the body weight loss of the hosts. Five xenografts were categorized in the cachectic group, and the remaining 21 xenografts belonged to the non-cachectic group. LIF was extensively expressed in both the cachectic and non-cachectic groups. ZAG and IL-6 were expressed in one of the cachectic and some non-cachectic xenografts. PIT and TNF alpha were detected in one and two non-cachectic xenografts, respectively, but in none of the cachectic ones. Any of five factors examined were not conclusive for causing cancer cachexia in the murine xenograft model. Further analysis is needed in order to elucidate the mechanisms responsible for cancer cachexia.