13q14 Deletion size and number of deleted cells both influence prognosis in chronic lymphocytic leukemia

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Blank13q14 Deletion size and number of deleted cells both influence prognosis in

chronic lymphocytic leukemia.

M Dal Bo, FM Rossi, D Rossi, C Deambrogi, F Bertoni, I Del Giudice, G Palumbo, M

Nanni, A Rinaldi, I Kwee, E Tissino, G Corradini, A Gozzetti, E Cencini, M

Ladetto, AM Coletta, F Luciano, P Bulian, G Pozzato, L ti, F Forconi, F Di

Raimondo, R Marasca, G Del Poeta, G Gaidano, R Foa, A Guarini, and V Gattei

Genes Chromosomes Cancer, May 11, 2011;

Clinical and Experimental Onco-Hematology Unit, Centro di Riferimento

Oncologico, I.R.C.C.S., Aviano (PN), Italy

Deletion at 13q14 is detected by fluorescence in situ hybridization (FISH) in

about 50% of chronic lymphocytic leukemia (CLL). Although CLL with 13q deletion

as the sole cytogenetic abnormality (del13q-only) usually have good prognosis,

more aggressive clinical courses are documented for del13q-only CLL carrying

higher percentages of 13q deleted nuclei. Moreover, deletion at 13q of different

sizes have been described, whose prognostic significance is still unknown. In a

multi-institutional cohort of 342 del13q-only cases and in a consecutive

unselected cohort of 265 CLL, we investigated the prognostic significance of 13q

deletion, using the 13q FISH probes locus-specific identifier (LSI)-D13S319 and

LSI-RB1 that detect the DLEU2/MIR15A/MIR16-1 and RB1 loci, respectively. Results

indicated that both percentage of deleted nuclei and presence of larger

deletions involving the RB1 locus cooperated to refine the prognosis of

del13q-only cases. In particular, CLL carrying <70% of 13q deleted nuclei with

deletions not comprising the RB1 locus were characterized by particularly long

time-to-treatment. Conversely, CLL with 13q deletion in <70% of nuclei but

involving the RB1 locus, or CLL carrying 13q deletion in ?70% of nuclei, with or

without RB1 deletions, collectively experienced shorter time-to-treatment. A

revised flowchart for the prognostic FISH assessment of del13q-only CLL,

implying the usage of both 13q probes, is proposed. 2011 Wiley-Liss, Inc.

PMID: 21563234