Droplet digital PCR analysis of NOTCH1 gene mutations in chronic lymphocytic leukemia.
In chronic lymphocytic leukemia (CLL), NOTCH1 gene mutations (NOTCH1mut) have been associated with adverse prognostic features but the independence of these as a prognostic factor is still controversial. In our study we validated a c.7541-7542delCT NOTCH1 mutation assay based on droplet digital PCR (ddPCR); we also analyzed the NOTCH1mut allelic burden, expressed as fractional abundance (FA), in 88 CLL patients at diagnosis to assess its prognostic role and made a longitudinal ddPCR analysis in 10 cases harboring NOTCH1mut to verify the FA variation over time. Our data revealed that with the ddPCR approach the incidence of NOTCH1mut in CLL was much higher (53.4%) than expected. However, longitudinal ddPCR analysis of CLL cases showed a statistically significant reduction of the NOTCH1mut FA detected at diagnosis after treatment (median FA 11.67 % vs 0.09 %, respectively, p = 0.01); the same difference, in terms of NOTCH1mut FA, was observed in the relapsed cases compared to the NOTCH1mut allelic fraction observed in patients in complete or partial remission (median FA 4.75% vs 0.43%, respectively, p = 0.007). Our study demonstrated a much higher incidence of NOTCH1mut in CLL than has previously been reported, and showed that the NOTCH1mut allelic burden evaluation by ddPCR might identify patients in need of a closer clinical follow-up during the "watch and wait" interval and after standard chemotherapy.
Department of Emergency and Organ Transplantation (D.E.T.O.), Hematology Section, University of Bari, Bari, 70124 Italy.
Angela
A
Minervini
Department of Emergency and Organ Transplantation (D.E.T.O.), Hematology Section, University of Bari, Bari, 70124 Italy.
Crescenzio
C
Francesco Minervini
Department of Emergency and Organ Transplantation (D.E.T.O.), Hematology Section, University of Bari, Bari, 70124 Italy.
Luisa
L
Anelli
Department of Emergency and Organ Transplantation (D.E.T.O.), Hematology Section, University of Bari, Bari, 70124 Italy.
Antonella
A
Zagaria
Department of Emergency and Organ Transplantation (D.E.T.O.), Hematology Section, University of Bari, Bari, 70124 Italy.
Paola
P
Casieri
Department of Emergency and Organ Transplantation (D.E.T.O.), Hematology Section, University of Bari, Bari, 70124 Italy.
Nicoletta
N
Coccaro
Department of Emergency and Organ Transplantation (D.E.T.O.), Hematology Section, University of Bari, Bari, 70124 Italy.
Cosimo
C
Cumbo
Department of Emergency and Organ Transplantation (D.E.T.O.), Hematology Section, University of Bari, Bari, 70124 Italy.
Giuseppina
G
Tota
Department of Emergency and Organ Transplantation (D.E.T.O.), Hematology Section, University of Bari, Bari, 70124 Italy.
Luciana
L
Impera
Department of Emergency and Organ Transplantation (D.E.T.O.), Hematology Section, University of Bari, Bari, 70124 Italy.
Paola
P
Orsini
Department of Emergency and Organ Transplantation (D.E.T.O.), Hematology Section, University of Bari, Bari, 70124 Italy.
Claudia
C
Brunetti
Department of Emergency and Organ Transplantation (D.E.T.O.), Hematology Section, University of Bari, Bari, 70124 Italy.
Annamaria
A
Giordano
Department of Emergency and Organ Transplantation (D.E.T.O.), Hematology Section, University of Bari, Bari, 70124 Italy.
Giorgina
G
Specchia
Department of Emergency and Organ Transplantation (D.E.T.O.), Hematology Section, University of Bari, Bari, 70124 Italy.
Francesco
F
Albano
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000188:drug therapy / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009154:Mutation; D016133:Polymerase Chain Reaction / Q000379:methods*; D051881:Receptor, Notch1 / Q000235:genetics*
C497761:NOTCH1 protein, human; D051881:Receptor, Notch1
IGHV mutational status; NOTCH1; chronic lymphocytic leukemia; droplet digital PCR; molecular monitoring