Abdominal Ultrasound in the Detection of an Incidental Paraganglioma.

Paraganglioma is a tumor that originates from neuroendocrine cells of the sympathetic or parasympathetic systems. Patients may suffer from headaches, palpitations, diaphoresis, and hypertension due to catecholamine excess or symptoms from the mass effect of the tumor. In the absence of typical symptoms of catecholamine excess, the diagnosis of a nonfunctional paraganglioma is often delayed. Herein, we report a case of a 63-year-old female patient with a nonfunctional paraganglioma which is an accidental finding during investigation of a fever. Abdominal ultrasonography incidentally detected this lesion as a complex, solid, cystic mass in the left suprarenal retroperitoneum.

Upregulation of caveolin-1 by mulberry leaf extract and its major components, chlorogenic acid derivatives, attenuates alcoholic steatohepatitis via inhibition of oxidative stress.

Excessive alcohol uptake exerts hepatocellular toxicity, ultimately leading to multiple liver diseases such as steatohepatitis and liver cirrhosis. Here, we aimed to explore the effects of mulberry leaf extract (MLE) and its major components chlorogenic acid (CGA) and neochlorogenic acid (nCGA) on alcoholic steatohepatitis. We determined the composition of MLE using liquid chromatography-mass spectrometric (LC-MS) analysis, which showed that MLE consisted of mainly chlorogenic acid derivatives and other polyphenols. Next, we utilized a high alcohol-fed mouse model and demonstrated that MLE alleviated alcohol-induced hepatocellular disorders, resulting in lowered hepatic injury markers and lipid accumulation. In addition, MLE reduced lipid peroxidation and meanwhile elevated hepatic superoxide dismutase (SOD). Immunohistochemical (IHC) staining revealed that MLE elevated the expression of caveolin-1 but reduced the expressions of epidermal growth factor receptor (EGFR), signal transducer and activator of transcription (STAT), inducible nitric oxide synthase (iNOS) and receptor interacting protein (RIP) 1/3. Major components of MLE, CGA and nCGA, not only exerted a similar biological activity as MLE but also inhibited alcohol-induced pro-apoptotic signals. Involvement of caveolin-1 in MLE, CGA and nCGA was demonstrated by using specific small inhibitory RNA. In conclusion, MLE and its chlorogenic derivatives CGA and nCGA upregulate caveolin-1 expression and diminish EGFR/STAT3/iNOS signalling, which may contribute to lowered hepatic lipid accumulation and peroxidation and inhibited pro-apoptotic cascades.

Mulberry water extract regulates the osteoblast/osteoclast balance in an ovariectomic rat model.

Mulberry has favorable antioxidant ability. Menopause is a major cause of osteoporosis in women, and it is partially associated with oxidative stress. Here, mulberry water extract (MWE) was fed to ovariectomic (OVX) rats to explore the potential effect of MWE on osteoporosis. The results revealed that plasma alkaline phosphatase (ALP) significantly decreased in the OVX rats after MWE administration for 8 weeks. Histological examination showed that the MWE increased the density of trabecular bone in the OVX rats. It also revealed that the MWE increases the expression of Runx2 and decreases that of the receptor activator of nuclear factor κB and its ligand in the OVX rats. This implies that MWE might regulate osteoblast differentiation and osteoclast proliferation. The MWE improved the antioxidant status by lowering the expression of heme oxygenase-1. In addition, the MWE increased the expression of osteocalcin, ALP, and bone morphogenetic protein-2 in an osteoblast cell line, MG-63. The present results imply that MWE has potential to decelerate osteoporosis in an experimental OVX rat model.

Primary Intestinal Diffuse Large B-cell Lymphoma in Taiwan Showed a Relative Higher Rate of Perforation and EBV Association.

We retrospectively investigated 59 surgically resected primary intestinal diffuse large B-cell lymphomas (PI-DLBCL) including 31 males and 28 females with a median age of 66. Eleven (19%) tumors were perforated at presentation; 8 (14%) were multicentric. Ileum (n=24; 43%) and ileocecum (n=17; 30%) were most frequently involved. Twenty-one (36%) patients did not receive chemotherapy or radiotherapy including 6 with perforation and died in 0.2 to 7 months. The 1-, 2-, and 5-year overall survival rates were 68.4%, 56.5%, and 50.0%, respectively. Seven (12%) of 59 cases were positive for Epstein-Barr virus (EBV) by in situ hybridization. IGH, BCL2, BCL6, and MYC foci were rearranged in 22%, 3%, 17%, and 7% cases, respectively, with 14% exhibiting gain/amplification at the MYC locus. Perforation (P=0.009), high ECOG PS (≥2) (P=0.018), and no adjuvant chemotherapy (P<0.001) were poor prognostic factors but not immunophenotype including co-expression of bcl-2 and myc, EBV status, or chromosomal aberrations. Perforation and chemotherapy remained significant by multivariate analysis. PI-DLBCL in Taiwan carried a relatively higher rate of perforation, lower frequency of germinal center B-cell phenotype, and higher EBV association as compared with studies from other geographic areas. Furthermore, perforation was a poor prognostic factor.

Myrciaria cauliflora extract improves diabetic nephropathy via suppression of oxidative stress and inflammation in streptozotocin-nicotinamide mice.

Myrciaria cauliflora is a functional food rich in anthocyanins, possessing antioxidative and anti-inflammatory properties. Our previous results demonstrated M. cauliflora extract (MCE) had beneficial effects in diabetic nephropathy (DN) and via the inhibition of Ras/PI3K/Akt and kidney fibrosis-related proteins. The purpose of this study was to assess the benefit of MCE in diabetes associated with kidney inflammation and glycemic regulation in streptozotocin-nicotinamide (STZ/NA)-induced diabetic mice. Compared with the untreated diabetic group, MCE significantly improved blood glucose and serum biochemical characteristic levels. Exposure to MCE increased antioxidative enzyme activity and diminished reactive oxygen synthesis. Mice receiving MCE supplementation had reduced intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), monocyte chemoattractant protein 1 (MCP-1), colony stimulating factor 1 (CSF-1), interleukin-1ß (IL-1ß), IL-6 and tumor necrosis factor α (TNF-α) levels compared to the untreated diabetic mice. Inflammatory and fibrotic related proteins such as collagen IV, fibronectin, Janus kinase (JAK), phosphorylated signal transducer and activator of transcription 3 (STAT3), protein kinase C beta (PKC-ß), and nuclear factor kappa B (NF-κB) were also inhibited by MCE treatment in STZ/NA mice. These results suggest that MCE may be used as a hypoglycemic agent and antioxidant in Type 2 diabetic mice.

Assessment of HER2 Status Using Immunohistochemistry (IHC) and Fluorescence In Situ Hybridization (FISH) Techniques in Mucinous Epithelial Ovarian Cancer: A Comprehensive Comparison between ToGA Biopsy Method and ToGA Surgical Specimen Method.

We aimed to compare the assay performance characteristics of HER2 status in mucinous epithelial ovarian cancer (EOC) by ToGA (Trastuzumab for Gastric Cancer) biopsy versus ToGA surgical specimen methods. Forty-nine tissue microarray (TMA) samples of mucinous EOC from Asian women were analyzed by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) tests using ToGA trial HER2 scoring methods. The overall concordance between IHC and FISH by the ToGA surgical specimen method is 97.56% and by the ToGA biopsy specimen method is 97.14%. The agreements of HER2 IHC results under both biopsy and surgical specimen methods were nearly perfect (weighted kappa = 0.845). Additionally, the percentage of Her2 FISH amplification showed increasing trend with increasing HER2 IHC ordinals (negative, equivocal, positive) by both TOGA biopsy (P<0.001) and surgical specimen method (P<0.001). After excluding equivocal cases, the sensitivity (100%), PPV (88.89%) and NPV (100%) of HER2 IHC were unchanged under either surgical specimen method or biopsy method. However, the specificity (96.97%) and accuracy (97.56%) of HER2 IHC was slightly higher under the surgical specimen method than those (specificity 96.30%, accuracy 97.14%) under the biopsy method. Of the total 49 cases, the number (n = 14) of HER2 IHC equivocal results under the ToGA biopsy method was 1.75-fold higher than those (n = 8) under the ToGA surgical specimen method (28.57% vs. 16.32%). Therefore, compared to ToGA surgery specimen method, the ToGA biopsy method caused more equivocal IHC cases to be referred to FISH testing and did not increase the detection rates of Her2 FISH amplification.

The metastatic tumor antigen 1-transglutaminase-2 pathway is involved in self-limitation of monosodium urate crystal-induced inflammation by upregulating TGF-ß1.

INTRODUCTION: Transglutaminase 2 (TG2), a protein crosslinking enzyme with multiple biochemical functions, has been connected to various inflammatory processes. In this study, the involvement of TG2 in monosodium urate (MSU) crystal-induced inflammation was studied. METHODS: Immunohistochemistry, reverse transcription-polymerase chain reaction (RT-PCR) were performed to detect TG2 expression in synovial fluid mononuclear cells (SFMCs) and synovial tissue from patients with gouty arthritis. MSU crystal-exposed RAW264.7 mouse macrophages were analyzed for interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNF-α), transforming growth factor ß1 (TGF-ß1) and TG2 expression by RT-PCR and enzyme-linked immunosorbent assay (ELISA). TG2 small interfering (si)-RNA-mediated silencing and overexpression in RAW264.7 cells were used to evaluate the involvement of TG2 in resolving MSU crystal-induced inflammation. The role of metastatic tumor antigen 1 (MTA1), a master chromatin modifier, was investigated by MTA1 si-RNA-mediated knockdown. In addition, the inflammatory responses were followed in wild type and TG2 null mice after being challenged with MSU crystals in an in vivo peritonitis model. RESULTS: TG2 expression was up-regulated in the synovium tissue and SFMCs from patients with gouty arthritis. The levels of MTA1, TG2, TGF-ß1, IL-1ß and TNF-α mRNAs were consistently increased in MSU crystal-stimulated RAW264.7 cells. si-MTA1 impaired the basal, as well as the MSU crystal-induced expression of TG2 and TGF-ß1, but increased that of IL-1ß and TNF-α. TG2 overexpression dramatically suppressed MSU crystal-induced IL-1ß and TNF-α, but significantly enhanced the TGF-ß1 production. Neutralizing TGF-ß antibodies or inhibition of the crosslinking activity of TG2 attenuated these effects. On the contrary, loss of TG2 resulted in a reduced TGF-ß, but in an increased IL-1ß and TNF-α production in MSU crystal-stimulated RAW264.7 cells and mouse embryonic fibroblasts (MEFs). MSU crystal-stimulated IL-1ß production was Janus kinase 2 (JAK2)-signaling dependent and TG2-induced TGF-ß suppressed the activity of it. Finally, TG2-deficient mice exhibited hyper inflammatory responses after being challenged with MSU crystals in an in vivo peritonitis model. CONCLUSIONS: These findings reveal an inherent regulatory role of the MTA1-TG2 pathway in the self-limitation of MSU crystal-induced inflammation via positively regulating the levels of active TGF-ß1 in macrophages that opposes the MSU crystal-induced JAK2-dependent pro-inflammatory cytokine formation.

Extranodal natural killer/T-cell lymphoma, nasal type in Taiwan: a relatively higher frequency of T-cell lineage and poor survival for extranasal tumors.

Extranodal natural killer (NK)/T-cell lymphoma, nasal type, is a predominantly extranodal lymphoma associated with Epstein-Barr virus occurring most frequently in the upper aerodigestive tract. There are limited reports on cellular origin and prognostic factors. We retrospectively investigated 73 cases with a median age of 54 years and a male-female ratio of 2.0:1. The upper aerodigestive tract (nasal group) was the most common site of involvement (51 cases; 70%). The other organs (n = 22; extranasal group) included the skin (12 cases; 16%) and gastrointestinal tract (5; 7%). Of the 70 cases with complete staging, 71% had stage I/II disease. All cases were positive for Epstein-Barr virus by in situ hybridization. Using immunohistochemistry and clonality assay for T-cell receptor gene rearrangement, these tumors were classified into NK (n = 39; 53%), T (n = 13; 18%), and indeterminate lineage (n = 21; 29%). The only clinicopathological difference among these 3 groups was rare CD5 expression in the NK-cell group. Nasal tumors were more frequently of NK-cell origin, and extranasal tumors were equally of either T- or NK-cell origin. The 5-year overall survival rate was 35.6%. The overall survival time was shorter in the extranasal group, although there was no statistical difference in age, sex, and histologic or immunophenotypic features between the 2 groups. Excluding the cases with indeterminate lineage, 75% of cases were of NK lineage; and 25%, T lineage. Extranasal tumors were more aggressive than their nasal counterparts. A prospective national study is warranted for a better understanding of the clinicopathological and genetic features of this uncommon tumor and the prognostic factors.

Spectrum of Epstein-Barr virus-associated T-cell lymphoproliferative disorder in adolescents and young adults in Taiwan.

Epstein-Barr Virus (EBV) is a herpesvirus usually infecting B-cells but may occasionally infect T- or natural killer (NK)-cells. EBV-associated T- or NK-cell lymphoproliferations represent a continuous spectrum of diseases ranging from asymptomatic infection, infectious mononucleosis (IM), to clonal and malignant lymphoproliferations including systemic EBV-positive T/NK-cell lymphoproliferative disease (EBV-T/NK-LPD) of childhood and hydroa-vacciniforme-like lymphoma of the skin. The clonal diseases are more prevalent in East Asia and exhibit overlapping clinical and pathological features with chronic active EBV infection. Here we report our experience on 10 cases of EBV-associated T-cell lymphoproliferation from Taiwan including five males and five females with a median age of 18 years old (range, 15-28). The most common clinical symptoms were fever, neck mass and hepatosplenomegaly. Eight of these patients showed elevated lactate dehydrogenase level and half of the patients had cytopenia. All patients had either elevated EBV antibody titers or increased serum EBV DNA levels. Five cases were clinically IM-like with polyclonal (3 cases) or clonal (2 cases) T-cell lymphoproliferation. Two patients each had chronic active EBV infection (CAEBV) and hemophagocytic lymphohistiocytosis (HLH). One patient had both CAEBV and HLH. One of the HLH patients with marrow infiltration by intra-sinusoidal large atypical lymphocytes experienced a fulminant course. In a median follow-up time of 21.5 months, seven patients were free of disease, one was alive with disease, and two died of disease in 31 and 3 months, respectively, despite chemotherapy. We confirmed a wide clinicopathological range of EVB-associated T-cell lymphoproliferation in Taiwan. Furthermore, monomorphic LPD and the single case with fulminant course as defined by Ohshima et al (Pathol Int 2018) as categories A3 and B, respectively, died of disease despite chemotherapy. Our report, the largest series in the recent decade from Taiwan, adds to the understanding of these rare diseases with variable clinical and histopathological presentations.

Topical N-acetylcysteine accelerates wound healing in vitro and in vivo via the PKC/Stat3 pathway.

N-Acetylcysteine (Nac) is an antioxidant administered in both oral and injectable forms. In this study, we used Nac topically to treat burn wounds in vitro and in vivo to investigate mechanisms of action. In vitro, we monitored glutathione levels, cell proliferation, migration, scratch-wound healing activities and the epithelialization-related proteins, matrixmetalloproteinase-1 (MMP-1) and proteins involved in regulating the expression of MMP-1 in CCD-966SK cells treated with Nac. Various Nac concentrations (0.1, 0.5, and 1.0 mM) increased glutathione levels, cell viability, scratch-wound healing activities and migration abilities of CCD-966SK cells in a dose-dependent manner. The MMP-1 expression of CCD-966SK cells treated with 1.0 mM Nac for 24 h was significantly increased. Levels of phosphatidylinositol 3-kinase (PI3K), protein kinase C (PKC), janus kinase 1 (Jak1), signal transducer and activator of transcription 3 (Stat3), c-Fos and Jun, but not extracellular signal-regulated protein kinases 1 and 2 (Erk1/2), were also significantly increased in a dose-dependent manner compared to the controls. In addition, Nac induced collagenous expression of MMP-1 via the PKC/Stat3 signaling pathway. In vivo, a burn wound healing rat model was applied to assess the stimulation activity and histopathological effects of Nac, with 3.0% Nac-treated wounds being found to show better characteristics on re-epithelialization. Our results demonstrated that Nac can potentially promote wound healing activity, and may be a promising drug to accelerate burn wound healing.

Decreased Kruppel-like factor 4 (KLF4) expression may correlate with poor survival in gastric adenocarcinoma.

Kruppel-like factors (KLFs) play either anti- or pro-proliferation roles in different human cancers. Here, we investigated the expression of KLF4 in gastric cancers and its correlation with clinicopathological parameters and overall survival. KLF4 expression was measured in 118 surgical specimens by immunohistochemical microarray assay. No association of cytoplasmic KLF4 expression with gender, TNM status, stage, survival, and pathological type was found. Using Kaplan-Meier analysis, significantly higher overall survival rate was observed in patients with high cytoplasmic KLF4 expression compared to low cytoplasmic KLF4 expression. Univariate analysis revealed that cytoplasmic KLF4 expression, grade, histological type, lymph node metastasis, and stages were correlated to longer overall survival. Our results suggest that KLF4 may play an anti-oncogenic role in gastric tumorigenesis.

Exacerbating effects of human parvovirus B19 NS1 on liver fibrosis in NZB/W F1 mice.

Systemic lupus erythematosus (SLE) is an autoimmune disorder with unknown etiology that impacts various organs including liver. Recently, human parvovirus B19 (B19) is recognized to exacerbate SLE. However, the effects of B19 on liver in SLE are still unclear. Herein we aimed to investigate the effects of B19 on liver in NZB/W F1 mice by injecting subcutaneously with PBS, recombinant B19 NS1, VP1u or VP2, respectively. Our experimental results revealed that B19 NS1 protein significantly enhanced the TGF-ß/Smad fibrotic signaling by increasing the expressions of TGF-ß, Smad2/3, phosphorylated Smad2/3, Smad4 and Sp1. The consequent fibrosis-related proteins, PAI-1 and α-SMA, were also significantly induced in livers of NZB/W F1 mice receiving B19 NS1 protein. Accordingly, markedly increased collagen deposition was also observed in livers of NZB/W F1 mice receiving B19 NS1 protein. However, no significant difference was observed in livers of NZB/W F1 mice receiving B19 VP1u or VP2 as compared to the controls. These findings indicate that B19 NS1 plays a crucial role in exacerbating liver fibrosis in NZB/W F1 mice through enhancing the TGF-â/Smad fibrotic signaling.

Human parvovirus B19 NS1 protein aggravates liver injury in NZB/W F1 mice.

Human parvovirus B19 (B19) has been associated with a variety of diseases. However, the influence of B19 viral proteins on hepatic injury in SLE is still obscure. To elucidate the effects of B19 viral proteins on livers in SLE, recombinant B19 NS1, VP1u or VP2 proteins were injected subcutaneously into NZB/W F1 mice, respectively. Significant expressions of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) were detected in NZB/W F1 mice receiving B19 NS1 as compared to those mice receiving PBS. Markedly hepatocyte disarray and lymphocyte infiltration were observed in livers from NZB/WF 1 mice receiving B19 NS1 as compared to those mice receiving PBS. Additionally, significant increases of Tumor Necrosis Factor -α (TNF-α), TNF-α receptor, IκB kinase -α (IKK-α), nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor (IκB) and nuclear factor-kappa B (NF-κB) were detected in livers from NZB/W F1 mice receiving B19 NS1 as compared to those mice receiving PBS. Accordingly, significant increases of matrix metalloproteinase-9 (MMP9) and U-plasminogen activator (uPA) were also detected in livers from NZB/W F1 mice receiving B19 NS1 as compared to those mice receiving PBS. Contrarily, no significant variation on livers from NZB/W F1 mice receiving B19 VP1u or VP2 was observed as compared to those mice receiving PBS. These findings firstly demonstrated the aggravated effects of B19 NS1 but not VP1u or VP2 protein on hepatic injury and provide a clue in understanding the role of B19 NS1 on hepatic injury in SLE.

Curcumin Protects against UVB-Induced Skin Cancers in SKH-1 Hairless Mouse: Analysis of Early Molecular Markers in Carcinogenesis.

Curcumin (CUR) has been shown to possess a preventive effect against various cancers and interfere with multiple-cell signaling pathways. We evaluated the protective effects of CUR in regression of UVB-induced skin tumor formation in SKH-1 hairless mice and its underlying early molecular biomarkers associated with carcinogenesis. Mice irradiated with UVB at 180 mJ/cm(2) twice per week elicited 100% tumor incidence at 20 weeks. Topical application of CUR prior to UVB irradiation caused delay in tumor appearance, multiplicity, and size. Topical application of CUR prior to and immediately after a single UVB irradiation (180 mJ/cm(2)) resulted in a significant decrease in UVB-induced thymine dimer-positive cells, expression of proliferative cell nuclear antigen (PCNA), terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling, and apoptotic sunburn cells together with an increase in p53 and p21/Cip1-positive cell population in epidermis. Simultaneously, CUR also significantly inhibited NF-κB, cyclooxygenase-2 (COX-2), prostaglandin E2 (PGE2), and nitric oxide (NO) levels. The results suggest that the protective effect of CUR against photocarcinogenesis is accompanied by downregulation of cell proliferative controls, involving thymine dimer, PCNA, apoptosis, transcription factors NF-κB, and of inflammatory responses involving COX-2, PGE2, and NO, while upregulation of p53 and p21/Cip1 to prevent DNA damage and facilitate DNA repair.

Loss of nuclear expression of Krüppel-like factor 4 is associated with poor prognosis in patients with oral cancer.

Krüppel-like factor 4 is not only involved in cell proliferation but also affects cell differentiation and extracellular matrix production via positive and negative regulation of the expression of a wide range of genes. To our knowledge, little information is available regarding the role of Krüppel-like factor 4 in oral squamous cell carcinoma. In this study, we investigated the associations between Krüppel-like factor 4 expression and clinical parameters of oral cancer using immunohistochemical assays in 215 surgical specimens. Compared with positive nuclear Krüppel-like factor 4 expression, we observed that negative nuclear Krüppel-like factor 4 expression was significantly associated with an advanced cancer stage (P = .046), a high tumor recurrence rate (P = .009), and a worse 3-year survival rate in patients with oral cancer (P = .046). Nuclear expression of Krüppel-like factor 4 was shown to have an inverse relationship with Ki67 expression (P = .046). Patients with negative nuclear expression of Krüppel-like factor 4 had significantly worse overall survival rates as defined by the log-rank test (P = .014). Patients with oral cancer with negative nuclear Krüppel-like factor 4 expression in tumor cells had poor prognoses and a 2.5-fold higher death risk. Compared with disease stage (P = .025), negative nuclear Krüppel-like factor 4 expression (P = .006) was an independent prognostic factor. Our results revealed that the loss of nuclear expression of Krüppel-like factor 4 is significantly associated with aggressive clinical manifestations and might be an adverse survival factor.

Curcumin alleviates eosinophilic meningitis through reduction of eosinophil count following albendazole treatment against Angiostrongylus cantonensis in mice.

Angiostrongylus cantonensis (A. cantonensis) is the most common cause of parasitic eosinophilic meningitis worldwide. By using an animal model of BALB/c mice infected with A. cantonensis, previous studies indicated that the anthelmintic drug, albendazole, could kill A. cantonensis larvae and prevent further infection. However, the dead larvae will induce severe immune responses targeting at brain tissues. To alleviate the detrimental effects caused by the dead larvae, we administered curcumin, a traditional anti-inflammatory agent, as a complementary treatment in addition to albendazole therapy, to determine whether curcumin could be beneficial for treatment. The results showed that although curcumin treatment alone did not reduce worm number, combined treatment by albendazole and curcumin helped to reduce eosinophil count in the cerebrospinal fluid, better than using albendazole alone. This alleviating effect did not affect albendazole treatment alone, since histological analysis showed similar worm eradication with or without addition of curcumin. Nevertheless, curcumin treatment alone and combined albendazole-curcumin treatment did not inhibit MMP-9 expression in the brain tissue. In conclusion, curcumin, when used as a complementary treatment to albendazole, could help to alleviate eosinophilic meningitis through suppression of eosinophil count in the cerebrospinal fluid.

High incidence of acute promyelocytic leukemia specifically induced by N-nitroso-N-methylurea (NMU) in Sprague-Dawley rats.

Carcinogenic agents such as N-methyl-N-nitrosourea can cause tumors. The aims of the present study were to evaluate and classify a subtype of AML (acute myeloid leukemia) that was induced by NMU. According to previous publications, NMU induces not only mammary cancer but also leukemia in Sprague-Dawley (S-D) rats. However, the subtype of leukemia involved in NMU-treated rats is unknown. We found that both organ weight and relative organ weights were significantly higher in NMU-exposed rats than in controls. Morphological changes of rat livers and spleens were assessed by histological evaluation (H&E staining), which found that these tissues were abnormal in appearance. Also, cytological examination of the blood showed immature white blood cells in a smear using Liu's and Papanicolaou stains, indicating that gross abnormalities and histopathological changes were pathologically observed. NMU leukemia incidence was 97.1%. In this study, immunohistochemical (IHC) analysis was valuable in classifying the leukemia of poorly differentiated blasts induced by NMU. Paraffin blocks were stained for MPO, CD3, CD15, CD20, and CD34 markers. The NMU-induced group was positive for MPO, but negative for CD3, CD15, CD20, and CD34. These CD markers suggest that they are useful in helping diagnose APL (M3) leukemia. The model of NMU-induced leukemogenesis in an S-D rat suggests a more definite way to classify APL. This APL will provide an important tool for chemical carcinogenesis and leukemia studies.