RESUMEN
The translocation t(5;12)(q31;p13)/ETV6::ACSL6 is a rare cytogenetic abnormality, although it is reported in various myeloid malignancies. To date, only 16 cases of t(5;12) and ETV6::ACSL6 rearrangement, confirmed by either molecular or Fluorescence In Situ Hyridization (FISH) analysis, have been reported. Eosinophilia is a distinctive and common feature associated with this rearrangement. Although few cases have been described, the prognosis of patients with ETV6::ACSL6 is considered poor. We report two additional cases of t(5;12)(q31;p13)/ETV6::ACLS6 rearrangement and eosinophilia. Unusually, in our cases, the ETV6::ACSL6 rearrangement occurred at the relapse of Acute Myeloid Leukemia (AML) patients who had t(6;9)(p23;q34)/DEK::NUP214 rearrangement at disease onset. The concurrence of these two rare abnormalities has never been reported and may suggest a cooperative role of t(5;12) and t(6;9), leading to disease relapse. Moreover, at relapse, both cases presented with eosinophilia, further strengthening the association of t(5;12) with eosinophilia in myeloid malignancies. Given the poor prognosis and the non-responsiveness to tyrosine kinase inhibitors of cases of ETV6::ACSL6 rearrangement, in contrast to cases of ETV6::PDGFRB rearrangement, we recommend the introduction of testing for this abnormality in myeloid malignancies with eosinophilia.
Asunto(s)
Eosinofilia , Leucemia Mieloide Aguda , Trastornos Mieloproliferativos , Proteínas Cromosómicas no Histona/genética , Aberraciones Cromosómicas , Eosinofilia/complicaciones , Eosinofilia/genética , Humanos , Hibridación Fluorescente in Situ , Leucemia Mieloide Aguda/complicaciones , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patología , Proteínas de Complejo Poro Nuclear/genética , Proteínas Oncogénicas/genética , Proteínas de Unión a Poli-ADP-Ribosa/genética , Recurrencia , Translocación GenéticaRESUMEN
Newly isolated strains of the ciliate Paramecium calkinsi and their cytoplasmic bacterial endosymbionts were characterized by a multidisciplinary approach, including live observation, ultrastructural investigation, and molecular analysis. Despite morphological resemblance, the characterized P. calkinsi strains showed a significant molecular divergence compared to conspecifics, possibly hinting for a cryptic speciation. The endosymbionts were clearly found to be affiliated to the species "Candidatus Trichorickettsia mobilis" (Rickettsiales, Rickettsiaceae), currently encompassing only bacteria retrieved in an obligate intracellular association with other ciliates. However, a relatively high degree of intraspecific divergence was observed as well, thus it was possible to split "Candidatus Trichorickettsia" into three subspecies, one of which represented so far only by the newly characterized endosymbionts of P. calkinsi. Other features distinguished the members of each different subspecies. In particular, the endosymbionts of P. calkinsi resided in the cytoplasm and possessed numerous peritrichous flagella, although no motility was evidenced, whereas their conspecifics in other hosts were either cytoplasmic and devoid of flagella, or macronuclear, displaying flagellar-driven motility. Moreover, contrarily to previously analyzed "Candidatus Trichorickettsia" hosts, infected P. calkinsi cells frequently became amicronucleate and demonstrated abnormal cell division, eventually leading to decline of the laboratory culture.