Guillermo Quintero

The Combined Expression Patterns of Ikaros Isoforms Characterize Different Hematological Tumor Subtypes

A variety of genetic alterations are considered hallmarks of cancer development and progression. The Ikaros gene family, encoding for key transcription factors in hematopoietic development, provides several examples as genetic defects in these genes are associated with the development of different types of leukemia. However, the complex patterns of expression of isoforms in Ikaros family genes has prevented their use as clinical markers. In this study, we propose the use of the expression profiles of the Ikaros isoforms to classify various hematological tumor diseases. We have standardized a quantitative PCR protocol to estimate the expression levels of the Ikaros gene exons. Our analysis reveals that these levels are associated with specific types of leukemia and we have found differences in the levels of expression relative to five interexonic Ikaros regions for all diseases studied. In conclusion, our method has allowed us to precisely discriminate between B-ALL, CLL and MM cases. Differences between the groups of lymphoid and myeloid pathologies were also identified in the same way.

Primary CNS plasmablastic lymphoma in an HIV/EBV negative patient: A case report.

Dear Editor, A 39-year-old Hispanic man without a significant past medical history was admitted to the hospital with a 6-day history of progressive left hemiparesis. He reported persistent headaches during the prior six months. On admission, the patient was alert and oriented. His physical examination was significant for hyper-reflexia and mild left side weakness without other associated neurological symptoms. Contrast-enhanced brain magnetic resonance imaging (MRI) revealed a right frontal lobe enhancing mass, measuring 40 mm 3 24 mm 3 24 mm with surrounding edema (Fig. 1A). He was taken to surgery where the H&E-stained imprint cytology and frozen section of intraoperative specimen revealed the presence of large tumor cells with morphologic features of plasmablast with eosinophilic cytoplasm and eccentric large nuclei with prominent nucleoli (Fig. 1B). Immunophenotypic studies of brain biopsy, using flow cytometry (FACSCanto ll flow cytometer (BDB), and Infinicyt software program (Cytognos, V1.4)) detected 92% of Lambda-restricted B-cells (Fig. 1C) that were CD202 (Fig. 1D), CD52, CD32, CD381 (Fig. 1E), CD101, CD451, CD191, BCL21. A diagnosis of plasmablastic lymphoma was then considered. The formalin-fixed paraffin-embedded tissue sections showed diffuse infiltration by cells with similar morphological characteristics of the intraoperative specimen (Fig. 1F). Immunohistochemical analysis revealed that tumor cells were CD20 (Fig. 1G) and ALK negative and showed strong positivity with CD138, MUM-1, CD38, CD10, MYC, and p53, (Figs. 1H–K), with a high index of proliferation of 80% (Fig. 1L) confirming plasmablastic lymphoma (PBL). Immunostains for HHV-8, cytomegalovirus, Simian virus 40, and in situ hybridization for Epstein– Barr virus (EBV) were negative (Fig. 1M). Fluorescence in situ hybridization (FISH) for MYC/IGH t (8;14) (q24;q32) was positive in tumor cells (Fig. 1N) and translocation t(14; 18) (q32; q21) was not detected (Vysis-Abbott) (Fig. 1O). Cerebrospinal fluid (CSF) cytology showed the presence of plasmablastic tumor cells (Fig. 1P) and flow cytometry stabilized with Transfix CSF identified 83.8% (98 cells/mL) of monoclonal B-cell population with immunophenotypic similar characteristics of the tumor cells of brain biopsy (Figs. 1Q–T). Staging with 18-FDG PET/CT (fluorodeoxyglucose positron emission tomography/computer tomography) was negative for other sites of involvement. Bone marrow histological examination and flow cytometry did not show involvement by lymphoma. HIV testing was negative. Serologies for hepatitis B, C, and Cytomegalovirus, were negative. The final diagnosis was a primary central nervous system plasmablastic lymphoma (PCNSPBL) in an immunocompetent patient. The patient received five cycles of systemic high-dose methotrexate (HD-MTX) with leucovorin rescue, cytarabine, and intrathecal methotrexate followed by whole brain radiation therapy. After 11 months the patient was alive, without neurological deficits. The MRI and CSF cytology were negative at this time (Fig. 1U); although the CFS flow cytometry showed 1.7% (0.1 cells/uL) of Lambda-restricted B-cells, CD202, CD451, CD381,CD191, CD101 (Figs. 1V–Y). Primary central nervous system lymphoma (PCNSL) is a rare brain tumor that accounts for 2–3% of all cases of non-Hodgkin’s lymphoma. It is limited to the brain parenchyma, intraocular compartment, cranial nerves, leptomeninges, and spinal cord. It is associated with a poor prognosis with a median survival of 14 and 2 months for immunocompetent and HIV-positive patients respectively. Approximately, 95% of PCNSL tumors are diffuse large B-cell lymphoma (DLBCL); and less commonly T-cell, *Correspondence to: Martha Romero, Fundaci on Santa Fe de Bogot a, Calle 119 No. 7-75, Bogot a, Colombia. E-mail: sanmalili@yahoo.com.ar § Both authors contributed equally to this work. Received 26 March 2015; Revised 21 August 2015; Accepted 24 September 2015 DOI: 10.1002/dc.23374 Published online 15 October 2015 in Wiley Online Library (wileyonlinelibrary.com).

El perfil de splicing del factor de transcripción ikaros caracteriza subtipos de neoplasias hematológicas

Introduccion La familia Ikaros de factores de transcripcion incluye genes cruciales en desarrollo hematopoyetico y que se han visto relacionados con el desarrollo de diferentes tipos de neoplasias hematologicas. Sin embargo, la compleja expresion de las isoformas en esta familia ha impedido cualquier utilidad clinica de las misma y esta el momento solo se ha caracterizado la presencia de ciertas isoformas en casos de leucemias y que, sin embargo, tambien aparecen en individuos sanos. Objetivo Basandonos en lo anterior, en el presente estudio se propone la estandarizacion una nueva metodologia que permita el estudio del conjunto completo de isoformas en la muestra, ya que todo parece indicar que es el desequilibrio de isoformas lo que se podria asociar a la enfermedad. Materiales y metodos Para ello se cuantificaron las regiones inter-exonicas de Ikaros a traves de qRT-PCR lo que permitio describir un perfil de expresion para el conjunto de isoformas presentes en cada paciente, que incluye diferencias de expresion de determinados exones, asi como presencia de procesamientos no canonicos. Resultados De esta manera hemos sido capaces de discriminar grupos de patologias, pudiendo discriminar grupos de leucemias linfoides agudas, leucemias linfoides cronicas, leucemias mieloides cronicas y mielomas multiples. Del mismo modo se encontraron diferencias entre los grupos de estirpe linfoides frente a los mieloides. Adicionalmente, se describio la evolucion del perfil de expresion de un paciente diagnosticado de leucemia mieloide cronica que evoluciono a leucemia linfoide aguda y que permitio observar variaciones moleculares en este tipo de patologias evolutivas. Conclusiones Estos resultados permiten inferir que el conjunto de isoformas Ikaros, y no la sobre-expresion de una sola de ellas, es caracteristico de la enfermedad y por tanto su estudio puede llegar a ser un buen marcador diagnostico. Ademas existen caracteristicas concretas, como la presencia de procesamientos no canonicos, que permitirian una implementacion rapida para el diagnostico de subgrupos dentro de algunas de las patologias y cuyo estudio es de alto interes ante la posibilidad de que supongan algun tipo de caracteristicas pronosticas.