Publication Date:
2012-12-21
Description:
The P2RY8-CRLF2 fusion defines a particular relapse-prone subset of childhood acute lymphoblastic leukemia (ALL) in Italian Association of Pediatric Hematology and Oncology Berlin-Frankfurt-Münster (AIEOP-BFM) 2000 protocols. To investigate whether and to what extent different clone sizes influence disease and relapse development, we quantified the genomic P2RY8-CRLF2 fusion product and correlated it with the corresponding CRLF2 expression levels in patients enrolled in the BFM-ALL 2000 protocol in Austria. Of 268 cases without recurrent chromosomal translocations and high hyperdiploidy, representing approximately 50% of all cases, 67 (25%) were P2RY8-CRLF2 positive. The respective clone sizes were ≥ 20% in 27% and 〈 20% in 73% of them. The cumulative incidence of relapse of the entire fusion-positive group was clone size independent and significantly higher than that of the fusion-negative group (35% ± 8% vs 13% ± 3%, P = .008) and primarily confined to the non–high-risk group. Of 22 P2RY8-CRLF2 –positive diagnosis/relapse pairs, only 4/8 had the fusion-positive dominant clone conserved at relapse, whereas none of the original 14 fusion-positive small clones reappeared as the dominant relapse clone. We conclude that the majority of P2RY8-CRLF2 –positive clones are small at diagnosis and virtually never generate a dominant relapse clone. Our findings therefore suggest that P2RY8-CRLF2 –positive clones do not have the necessary proliferative or selective advantage to evolve into a disease-relevant relapse clone.
Keywords:
Free Research Articles, Lymphoid Neoplasia, 〈a href="/content/by/section/Editorials"〉Editorials〈/a〉, Clinical Trials and Observations
Print ISSN:
0006-4971
Electronic ISSN:
1528-0020
Topics:
Biology
,
Medicine
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