Promyelocytic sarcoma of the sternum: a case report and review of the literature

This study reports a case of promyelocytic sarcoma that developed as a solitary sternal mass without any clinical evidence of acute promyelocytic leukemia. The case presented the diagnostic difficulties common to all aleukemic granulocytic sarcomas, and diagnosis was made possible by local identification of the PML/RARalpha fusion gene by fluorescent in situ hybridization. The patient was treated by surgery followed by chemotherapy plus all-trans retinoic acid therapy and local radiotherapy.

PML-RARalpha gene detection method optimization for quantitative PCR

Hybrid gene PML-RARα is the molecular target found in most cases of acute promyelocytic leukemia (APL) and has been used for diagnosis and minimal residual disease studies. The standard molecular technique employed is qualitative reverse transcriptase-polymerase chain reaction (RT-PCR), but with the emergence of real time PCR (Q-PCR), PML-RARα gene detection approaches have been described allowing transcript detection, with the methodological advantage of eliminating post-PCR processing. However, current protocols report the use of expensive fluorescent labeled probes, limiting its routine application in the laboratory. The objective of this study was to optimize PML-RARalpha gene detection method for Q-PCR, using SYBR® Green fluorescent dye. The analysis was performed with NB4 cellular lineage cDNA. Thermal cycling protocols, cDNA synthesis with random or specific primer and different MgCl2 and amplification primers concentrations were tested. Results show that amplification improved in the following conditions: 2 mM MgCl2, 10 pmol primers and cDNA synthesized with specific primer. There were no significant differences using annealing temperature (58ºC/30 s) followed by extension (72ºC/30 s) or annealing associated with extension as a single step (60ºC/45 s). This paper demonstrates the optimization of PML-RARα gene detection for Q-PCR studies using a technique considered sensitive and less expensive for routine use in the laboratory.

O gene híbrido PML-RARα é o marcador molecular presente na maioria dos casos de leucemia aguda promielocítica (LAP), sendo útil ao diagnóstico e ao estudo da doença residual mínima. A técnica molecular empregada como rotina laboratorial é a reação em cadeia da polimerase com transcrição reversa (RT-PCR) qualitativa, porém com o surgimento da PCR em tempo real (Q-PCR), foram descritas abordagens de detecção do gene PML-RARalfa possibilitando a quantificação de transcritos, com a vantagem metodológica da eliminação do processamento pós-PCR. No entanto, os protocolos relatam o uso de sondas fluorescentes de custo elevado para a rotina clínica, limitando sua aplicação. Este estudo teve como objetivo otimizar o método de detecção do gene PML-RARα para Q-PCR, utilizando como sistema de marcação fluorescente o intercalante SYBR® Green. A análise foi realizada com cDNA da linhagem celular NB4, tendo sido testados protocolos de termociclagem, síntese de cDNA com primer randômico ou específico e diferentes concentrações de MgCl2 e primers para amplificação. Os resultados mostraram amplificação mais eficiente nas seguintes condições: 2 mM MgCl2, 10 pmol de primers e cDNA sintetizado com primer específico. Não houve diferença na utilização de etapas para anelamento (58ºC/30 s) seguido de extensão (72ºC/30 s) ou etapa única de anelamento associado à extensão (60ºC/45 s). Esses resultados demonstram a otimização da detecção do gene PML-RARα para Q-PCR através de um método considerado sensível e de baixo custo para a rotina laboratorial.

A Case of Acute Promyelocytic Leukemia with 46, XX, del(5)(q23)/47, XX, del(5)(q23), +8 but Without (15;17) Translocation / 대한혈액학회지

Acute promyelocytic leukemia (APL/AML- M3) is a distinct subtype of acute myelogenous leukemia, which is characterized by unique morphologic, cytogenetic, molecular, and clinical features. In almost all APL patients, a characteristic t(15;17)(q22;q21) is found, resulting from the fusion of the PML gene and retinoic acid receptor alpha (RAR ) gene. This chromosomal translocation in APL may present variant translocations, and may be associated with secondary chromosomal abnormalities. The most frequent accompanying karyotypic aberration is trisomy 8 in APL. We are reporting a case of a 17-year-old woman who was diagnosed with APL. Cytogenetic study revealed that 46, XX, del(5)(q23)/47, XX, del(5)(q23), +8 chromosomal abnormality but without t(15;17). However, the presence of PML/RAR chimera was found with reverse transcriptase PCR. It is well known that the association of trisomy 8 on top of t(15;17) in APL cases. However, in our review, the mosaicism of del(5)(q23) with trisomy 8 in APL might be the first case. Whether this patient will behave the typical APL cases having good prognosis or not will be interesting to see.