Acute-type Adult T-cell leukemia/lymphoma (ATLL) is classified into four clinical subtypes (Acute, Lymphoma, Chronic and Smoldering). Acute-type ATLL comprises clinically heterogeneous groups because this subtype is defined as a group not classified into three other subtypes. When lymphoma-type progress to show PBL involvement of more than 1%, it becomes acute-type ATLL. We tentatively designate such cases showing leukemic cells in peripheral blood with prominent nodal involvement as “acute-type ATLL-PNI”. Clarification of the molecular basis for clinical heterogeneity of Acute-type ATLL is an important issue for therapeutic strategy. We previously studied acute-type ATLL with fulminating leukemic manifestation (more than 60% leukemic cells in peripheral blood) by array CGH and identified a part of the molecular basis for the ATLL subtype (

Oshiro et al.,
Blood
107
:
4500
,
2006
). Here we analyzed six such cases of “acute-type ATLL-PNI” by means of array CGH consisting of 2304 artificial chromosome clones that cover the whole genome at a 1.3 mega base resolution. Regions of recurrent gain were detected on 2p16.1, 3p26.3-26.1, 3p24.2-24.1, 3p22.2-22.1, 3p14.3, 3p14.2-3q13.3, 3q25.32-26.2, 3q26.31-26.33, 3q27.3-29, 6p25.3-24.1, 7q32.3-33 and 17q23.3-24.2 and regions of recurrent loss on 4q21.22-21.23, 6q13-16.3 and 13q32.1-33.1. We compared the genomic profile of these six cases of “acute-type ATLL-PNI” with that of 49 lymphoma-type ATLL cases previously reported by us (Oshiro et al., Blood, 2006). They were very similar to each other and thirteen of the 15 regions of recurrent genomic imbalance in “acute-type ATLL-PNI” were also found in lymphoma-type ATLL (86.7%). Our findings clearly showed that “acute-type ATLL-PNI” have genomic imbalances in common with lymphoma-type ATLL rather than acute-type. Our array data also indicated that “clinically defined” acute-type ATLL contained leukemic-type and lymphoma-type with leukemic transformation.

Disclosures: No relevant conflicts of interest to declare.

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