FLI1 and MIC2 expression in precursor B-lymphoblastic leukemia with Burkitt-like morphology and extensive extramedullary involvement: A diagnostic challenge in pediatric small round cell tumor

Pediatric small round cell tumors (PSRCTs) constitute a large proportion of childhood malignancies with overlapping diagnostic and clinical features but radically different therapies. Here, we report a case of 16-year-old male child presenting with diffuse abdominal and mediastinal mass, axillary lymphadenopathy, and pleural effusion. Bone marrow aspirate showed near total replacement by small round malignant cells. The bone marrow biopsy showed interstitial infiltration by malignant cells, which were CD45? CD3? CD20? MIC2+ FLI1+ and diagnosis of Ewing's sarcoma was established. In contrast, flowcytometric immunophenotyping of the bone marrow aspirate showed CD45? cells, which were CD19+ cytCD79a+ CD10+ CD81+ CD38+ HLA-DR+ CD22+ CD20? consistent with B-cell acute lymphoblastic leukemia (B-ALL). The extended immunostaining panel on bone marrow biopsy also showed positivity for cytCD79a, CD10, CD19, and BCL-2, whereas fluorescent in-situ hybridization for EWSR1 gene rearrangement was negative. Thus, a final diagnosis of CD45? FLI1+ MIC2+ B-ALL was established. Rare cases of CD45? B-ALL with immunoreactivity for MIC2 and Friend leukemia virus integration 1 (FLI1) have posed a diagnostic challenge for PSRCTs in the recent past. This case report highlights the role of multimodality approach in establishing a correct diagnosis in CD45? PSRCTs to ensure definitive therapy and better clinical outcome.

Identification of interaction site of MIC2 with aldolase in Toxoplasma gondii / 中国人兽共患病学报

In this study ,we aim to identify the protein interaction site of microneme protein 2 (MIC2) and aldolase in Toxoplasma gondii .The tryptophan (Trp ,W) at site 767 of carboxyl terminus of MIC2 (MIC2C) was mutated into alanine (Ala ,A) by site-directed mutagenesis to construct plasmid MIC2C W/A/pGEX-4T-1 .The mutant protein GST-MIC2C W/A was expressed in E .coli upon IPTG induction .Glutathione sepharose beads were incubated with GST-MIC2C W/A and GST-MIC2C respectively ,then incubated with tachyzoite lysates ,and bound proteins were eluted using sample buffer .Eluants were resolved by SDS-PAGE and Western blot .A protein band specifically recognized by anti-aldolase antibody was detected in prod-ucts coming from GST pull-down of GST-MIC2C ,but not in pull-down products coming from GST-MIC2C W/A .With muta-tion of MIC2C W767 to A ,MIC2 protein lost the binding ability to aldolase .Tryptophan (W767 ) was the protein interaction site of MIC2 and aldolase in T .gondii .

High Expression of Water-Soluble Recombinant Antigenic Domains of Toxoplasma gondii Secretory Organelles

Recombinant antigenic proteins of Toxoplasma gondii are alternative source of antigens which are easily obtainable for serodiagnosis of toxoplasmosis. In this study, highly antigenic secretory organellar proteins, dense granular GRA2 and GRA3, rhoptrial ROP2, and micronemal MIC2, were analyzed by bioinformatics approach to express as water-soluble forms of antigenic domains. The transmembrane region and disorder tendency of 4 secretory proteins were predicted to clone the genes into pGEX-4T-1 vector. Recombinant plasmids were transformed into BL21 (DE3) pLysS E. coli, and GST fusion proteins were expressed with IPTG. As a result, GST fusion proteins with GRA225-105, GRA339-138, ROP2324-561, and MIC21-284 domains had respectively higher value of IgG avidity. The rGST-GRA225-105 and rGST-GRA339-138 were soluble, while rGST-ROP2324-561 and rGST-MIC21-284 were not. GRA231-71, intrinsically unstructured domain (IUD) of GRA2, was used as a linker to enhance the solubility. The rGST-GRA231-71-ROP2324-561, a chimeric protein, appeared to be soluble. Moreover, rGST-GRA231-71-MIC21-284 was also soluble and had higher IgG avidity comparing to rGST-MIC21-284. These 4 highly expressed and water-soluble recombinant antigenic proteins may be promising candidates to improve the serodiagnosis of toxoplasmosis in addition to the major surface antigen of SAG1.

Small Cell Osteosarcoma Similar to Ewing's Sarcoma in Histologic Findings and MIC2 Expression: A case report

Small cell osteosarcoma is a rare form of osteosarcoma and the histological differential diagnosis from other small round cell tumors (SRCTs) is difficult. The immunohistochemical stain for MIC2 has been considered an useful diagnostic marker for Ewing's sarcoma and primitive neuroectodermal tumors but recently, other SRCTs such as malignant lymphoma and embryonal rhabdomyosarcoma also showed positive reaction. Therefore, the usefulness of MIC2 must still be proven. We experienced a case of small cell osteosarcoma of the mandible in a 25-year-old man. Histologically, the tumor consisted of small round cells that resembled those of Ewing's sarcoma. Immunohistochemically, the tumor cells expressed diffuse strong positive reaction for MIC2 gene products. However, the scanty foci of lacy osteoid material between the tumor cells seemed to be diagnostic of osteosarcoma. The histologic and immunohistochemical findings of this case suggest close relationship between small cell osteosarcoma and Ewing's sarcoma.

The Distribution of MIC2 Antigen (CD99) Expression on Various Mucosa-Associated Lymphoid Tissue of Human Embryos and Fetuses / 대한면역학회지

In the present study, we examined to determine the development of various lymphoid tissue including mucosa-associated lymphoid tissue (MALT), thymus, lymph node and liver. In order to investigate the relationship between the morphological events and the expression pattern of MIC2 antigen (CD99) during the development of lymphoid system, we performed the immunohistochemical study using DN16, a monoclonal antibody against MIC2 (CD99), on formalin-fixed and paraffin-embedded lymphoid sections in 68 human embryos and fetuses, between 5 and 39 gestational week (GW). Four neonates, an infant, and 5 adults are also included. CD99 has been expressed along the membrane of hepatocytes and sinusoidal endothelial cells for 10-28 GW, in when the liver the major site of hematopoiesis. In the thymus, CD99 was firstly detected in the presumptive epitheial cells at 10 GW. When the thymus matured and corticomedullary differentiation appeared, CD99 was exclusively expressed in cortical thymocytes. The CD99 expression in epithelial cells of MALT has initiated at 6 GW and 10 GW earlier than that at the onset of MALT development and its expression has been persisted during MALT formation especially 16-25 GW. The finnding that CD99 antigen was expressed in epithelial cells during the development of MALT rnight provide a means to identify a novel epithelial differentiated substance. In addition, endothelial cells that are present in various organs such as liver and small intestine concurrently expressed CD99 antigen and its expression persisted to late fetal period. This point rnight suggest that CD99 antigen regulate the irnigration of lymphocytes from liver, major hematopoietic organ, to thymus or peripheral lyrnphoid organ via the interaction between endothelial cells and lymphocytes.

Histopathologic Re-evaluation of Thymoma with Immunonhistochemical Study for bcl-2 and MIC-2 Protein

We reviewed 86 thymic epithelial tumors and reclassified them according to the Kirchner and Muller- Hermelink classification. They were subtyped as medullary, mixed, predominantly cortical (organoid), cortical, well differentiated thymic carcinoma, and poorly differentiated thymic carcinoma. The frequency of each subtype was determined and histologic findings were related to stage and myasthenia gravis. Immunohistochemical stains for bcl-2 protein as a marker for medullary thymocytes and MIC-2 protein as a marker for cortical thymocytes were performed in each case. The stages and association of myasthenia gravis was significantly different in each subtypes. The results of this study demonstrate that this histogenetic classification is clinically applicable. The bcl-2 protein was specifically demonstrated in lymphocytes within areas of medullary differentiation and MIC-2 protein in cortical differentiation. The expression of bcl-2 and MIC-2 proteins lend histogenetic support for this new classification of thymoma. Bcl-2 protein is strongly expressed in tumor epithelial cells of every case of poorly differentiated thymic carcinoma whereas the other types of thymic epithelial tumors do not show epithelial expression of this protein. The strong expression of bcl-2 protein in tumor epithelium may be considered as a predictor of aggressive behavior in thymic epithelial tumors.

Expression of mic2/CD99 protein and their correlation with Eber-1/LMP-1 in Hodgkin and Reed-Sternberg cells of classical Hodgkin's lymphoma / 中国病理生理杂志

AIM: To study the expression of mic2/CD99 protein and their correlation with Eber-1/LMP-1 in Hodgkin and Reed-Sternberg cells of classical Hodgkin's lymphoma. METHODS: Immunohistochemical staining, in situ hybrization and tissue microarry technique were used to detect the expressions of mic2/CD99 and Eber-1/LMP-1 of H/RS cells in 43 cases of cHL and 16 cases of NHL. RESULTS: The positive rate of CD99 protein expression in 43 cases of cHL was 2.3% (1/43) , mic2 was 55.8% (24/43), LMP1 was 58.1% (25/43) and Eber-1 was 53.5% (23/43). The expressions of CD99 and mic2 in the NHL group were higher than those in cHL group (P0.05). There was a negative correlation between the expression of CD99 protein and LMP1 in H/RS cells (P0.05). There was a significant correlation between the high expression of LMP1 and a low expression of CD99 in the young patients (P0.05). CONCLUSION: There is a negative correlation between the expression of LMP1 and CD99 in Hodgkin and Reed-Sternberg cells of classical Hodgkin's lymphoma.