MOLECULAR LANDSCAPE OF PRIMARY AND RELAPSED ACUTE PROMYELOCYTIC LEUKEMIA
(Abstract release date: 05/19/16)
EHA Library. Fasan A. 06/09/16; 132437; E888
Disclosure(s): Employed by MLL Munich Leukemia Laboratory
Dr. Annette Fasan
Contributions
Contributions
Abstract
Abstract: E888
Type: Eposter Presentation
Background
Acute promyelocytic leukemia (APL) with t(15;17)(q22;q12)/PML-RARA accounts for ~5% of adult AML. Two therapeutic agents, ATRA and arsenic trioxide (ATO), induce differentiation of promyelocytes in vivo resulting in complete remission. However, some patients still relapse after ATO-ATRA based treatments and the mechanisms associated with resistance to these agents are still poorly understood.
Aims
The evaluation of the mutational spectrum of APL both at initial diagnosis and relapse.
Methods
We analyzed a cohort of 124 de novo APL cases including 14 cases who showed hematologic or molecular relapse. All patients (pts) were proven to have t(15;17)(q22;q12)/PML-RARA by chromosome banding analysis (CBA) (n=114), fluorescence in situ hybridization (n=120) and/or RT-PCR (n=124). 69 pts were male and 55 pts were female with a median age of 47 years (range: 16-84 years). All 124 samples were analyzed by next generation sequencing (NGS) using a 24-gene panel targeting ASXL1, CBL, CSF3R, DNMT3A, ETNK1, ETV6, EZH2, FLT3-TKD, GATA2, IDH1, IDH2, KIT, KRAS, NPM1, NRAS, RUNX1, SETBP1, SF3B1, SRSF2, TET2, TP53, U2AF1, WT1 and ZRSR2. FLT3-ITD was analyzed by gene scan. Relapse samples were screened for mutations within the PML-RARA fusion transcript by direct Sanger sequencing.
Results
Using standard CBA, additional cytogenetic aberrations were observed in 44/114 pts (27%). The most frequent secondary chromosome aberration was +8 (14/44; 32%). Using NGS 77/124 pts (62%) had at least one mutation (mut) in addition to PML-RARA, 17/77 (22%) had ≥2 additional mut (maximum: four). Most common were mutations in FLT3 (FLT3-ITD: 47/124, 38%, FLT3-TKD: 15/124; 12%) and WT1 (13/124, 10%). Mutations in other genes (ASXL1, CBL, DNMT3A, ETV6, KRAS, NRAS, RUNX1, SF3B1 and TET2) were found in less than 10% of cases, respectively. Comparing the initial mutational pattern of pts who relapsed during the course of disease with those staying in molecular remission revealed no difference in concomitant molecular mutations. Solely the percentage of pts with concomitant mutations was higher in the relapse group (79% vs. 60%; n.s.). Survival analysis revealed no influence of concomitant mutations in individual genes on prognosis. Also the amount of additional mutations had no prognostic impact. In selected cases (n=14/124), we compared changes in the patterns of genetic lesions between initial diagnosis and relapse. In 8/14 (57%) pts the initial mutation pattern changed at relapse. Mutations gained at relapse were WT1 (2/14, 14%) followed by DNMT3A, ETV6, FLT3-TKD, RUNX1 and TP53 (each 1/14, 7%). Loss of mutations was observed in FLT3-TKD, WT1 (each 2/14, 14%) as well as in ASXL1, FLT3-ITD and NRAS (each 1/14, 7%). In 4/14 relapsed pts (29%), mutations within the PML-RARA fusion transcript were detected. In none of the cases these mutations were detectable at initial diagnosis and thus all were acquired mutations. Missense mutations in the ligand binding domain of RARA were detected in 3 relapsed pts (p.Arg272Gln, p.Arg276Trp and p.Ser287Leu). In one relapsed APL pt, a mutation in the B2 domain of PML was observed (p.Ala216His). All mutations occurred in post-ATRA-relapse.
Conclusion
1) 62% of APL cases carry additional molecular mutations. 2) The most frequent additional molecular mutation is FLT3-ITD (38%) followed by FLT3-TKD mutations (12%) and mutations in WT1 (10%). 3) In 57% of relapsed APL the molecular mutation pattern changes. 4) Acquired mutations within the PML-RARA fusion transcript are detected in 29% of relapsed APL patients.
Session topic: E-poster
Keyword(s): APL, Molecular markers, PML-RAR, Relapse
Type: Eposter Presentation
Background
Acute promyelocytic leukemia (APL) with t(15;17)(q22;q12)/PML-RARA accounts for ~5% of adult AML. Two therapeutic agents, ATRA and arsenic trioxide (ATO), induce differentiation of promyelocytes in vivo resulting in complete remission. However, some patients still relapse after ATO-ATRA based treatments and the mechanisms associated with resistance to these agents are still poorly understood.
Aims
The evaluation of the mutational spectrum of APL both at initial diagnosis and relapse.
Methods
We analyzed a cohort of 124 de novo APL cases including 14 cases who showed hematologic or molecular relapse. All patients (pts) were proven to have t(15;17)(q22;q12)/PML-RARA by chromosome banding analysis (CBA) (n=114), fluorescence in situ hybridization (n=120) and/or RT-PCR (n=124). 69 pts were male and 55 pts were female with a median age of 47 years (range: 16-84 years). All 124 samples were analyzed by next generation sequencing (NGS) using a 24-gene panel targeting ASXL1, CBL, CSF3R, DNMT3A, ETNK1, ETV6, EZH2, FLT3-TKD, GATA2, IDH1, IDH2, KIT, KRAS, NPM1, NRAS, RUNX1, SETBP1, SF3B1, SRSF2, TET2, TP53, U2AF1, WT1 and ZRSR2. FLT3-ITD was analyzed by gene scan. Relapse samples were screened for mutations within the PML-RARA fusion transcript by direct Sanger sequencing.
Results
Using standard CBA, additional cytogenetic aberrations were observed in 44/114 pts (27%). The most frequent secondary chromosome aberration was +8 (14/44; 32%). Using NGS 77/124 pts (62%) had at least one mutation (mut) in addition to PML-RARA, 17/77 (22%) had ≥2 additional mut (maximum: four). Most common were mutations in FLT3 (FLT3-ITD: 47/124, 38%, FLT3-TKD: 15/124; 12%) and WT1 (13/124, 10%). Mutations in other genes (ASXL1, CBL, DNMT3A, ETV6, KRAS, NRAS, RUNX1, SF3B1 and TET2) were found in less than 10% of cases, respectively. Comparing the initial mutational pattern of pts who relapsed during the course of disease with those staying in molecular remission revealed no difference in concomitant molecular mutations. Solely the percentage of pts with concomitant mutations was higher in the relapse group (79% vs. 60%; n.s.). Survival analysis revealed no influence of concomitant mutations in individual genes on prognosis. Also the amount of additional mutations had no prognostic impact. In selected cases (n=14/124), we compared changes in the patterns of genetic lesions between initial diagnosis and relapse. In 8/14 (57%) pts the initial mutation pattern changed at relapse. Mutations gained at relapse were WT1 (2/14, 14%) followed by DNMT3A, ETV6, FLT3-TKD, RUNX1 and TP53 (each 1/14, 7%). Loss of mutations was observed in FLT3-TKD, WT1 (each 2/14, 14%) as well as in ASXL1, FLT3-ITD and NRAS (each 1/14, 7%). In 4/14 relapsed pts (29%), mutations within the PML-RARA fusion transcript were detected. In none of the cases these mutations were detectable at initial diagnosis and thus all were acquired mutations. Missense mutations in the ligand binding domain of RARA were detected in 3 relapsed pts (p.Arg272Gln, p.Arg276Trp and p.Ser287Leu). In one relapsed APL pt, a mutation in the B2 domain of PML was observed (p.Ala216His). All mutations occurred in post-ATRA-relapse.
Conclusion
1) 62% of APL cases carry additional molecular mutations. 2) The most frequent additional molecular mutation is FLT3-ITD (38%) followed by FLT3-TKD mutations (12%) and mutations in WT1 (10%). 3) In 57% of relapsed APL the molecular mutation pattern changes. 4) Acquired mutations within the PML-RARA fusion transcript are detected in 29% of relapsed APL patients.
Session topic: E-poster
Keyword(s): APL, Molecular markers, PML-RAR, Relapse
Abstract: E888
Type: Eposter Presentation
Background
Acute promyelocytic leukemia (APL) with t(15;17)(q22;q12)/PML-RARA accounts for ~5% of adult AML. Two therapeutic agents, ATRA and arsenic trioxide (ATO), induce differentiation of promyelocytes in vivo resulting in complete remission. However, some patients still relapse after ATO-ATRA based treatments and the mechanisms associated with resistance to these agents are still poorly understood.
Aims
The evaluation of the mutational spectrum of APL both at initial diagnosis and relapse.
Methods
We analyzed a cohort of 124 de novo APL cases including 14 cases who showed hematologic or molecular relapse. All patients (pts) were proven to have t(15;17)(q22;q12)/PML-RARA by chromosome banding analysis (CBA) (n=114), fluorescence in situ hybridization (n=120) and/or RT-PCR (n=124). 69 pts were male and 55 pts were female with a median age of 47 years (range: 16-84 years). All 124 samples were analyzed by next generation sequencing (NGS) using a 24-gene panel targeting ASXL1, CBL, CSF3R, DNMT3A, ETNK1, ETV6, EZH2, FLT3-TKD, GATA2, IDH1, IDH2, KIT, KRAS, NPM1, NRAS, RUNX1, SETBP1, SF3B1, SRSF2, TET2, TP53, U2AF1, WT1 and ZRSR2. FLT3-ITD was analyzed by gene scan. Relapse samples were screened for mutations within the PML-RARA fusion transcript by direct Sanger sequencing.
Results
Using standard CBA, additional cytogenetic aberrations were observed in 44/114 pts (27%). The most frequent secondary chromosome aberration was +8 (14/44; 32%). Using NGS 77/124 pts (62%) had at least one mutation (mut) in addition to PML-RARA, 17/77 (22%) had ≥2 additional mut (maximum: four). Most common were mutations in FLT3 (FLT3-ITD: 47/124, 38%, FLT3-TKD: 15/124; 12%) and WT1 (13/124, 10%). Mutations in other genes (ASXL1, CBL, DNMT3A, ETV6, KRAS, NRAS, RUNX1, SF3B1 and TET2) were found in less than 10% of cases, respectively. Comparing the initial mutational pattern of pts who relapsed during the course of disease with those staying in molecular remission revealed no difference in concomitant molecular mutations. Solely the percentage of pts with concomitant mutations was higher in the relapse group (79% vs. 60%; n.s.). Survival analysis revealed no influence of concomitant mutations in individual genes on prognosis. Also the amount of additional mutations had no prognostic impact. In selected cases (n=14/124), we compared changes in the patterns of genetic lesions between initial diagnosis and relapse. In 8/14 (57%) pts the initial mutation pattern changed at relapse. Mutations gained at relapse were WT1 (2/14, 14%) followed by DNMT3A, ETV6, FLT3-TKD, RUNX1 and TP53 (each 1/14, 7%). Loss of mutations was observed in FLT3-TKD, WT1 (each 2/14, 14%) as well as in ASXL1, FLT3-ITD and NRAS (each 1/14, 7%). In 4/14 relapsed pts (29%), mutations within the PML-RARA fusion transcript were detected. In none of the cases these mutations were detectable at initial diagnosis and thus all were acquired mutations. Missense mutations in the ligand binding domain of RARA were detected in 3 relapsed pts (p.Arg272Gln, p.Arg276Trp and p.Ser287Leu). In one relapsed APL pt, a mutation in the B2 domain of PML was observed (p.Ala216His). All mutations occurred in post-ATRA-relapse.
Conclusion
1) 62% of APL cases carry additional molecular mutations. 2) The most frequent additional molecular mutation is FLT3-ITD (38%) followed by FLT3-TKD mutations (12%) and mutations in WT1 (10%). 3) In 57% of relapsed APL the molecular mutation pattern changes. 4) Acquired mutations within the PML-RARA fusion transcript are detected in 29% of relapsed APL patients.
Session topic: E-poster
Keyword(s): APL, Molecular markers, PML-RAR, Relapse
Type: Eposter Presentation
Background
Acute promyelocytic leukemia (APL) with t(15;17)(q22;q12)/PML-RARA accounts for ~5% of adult AML. Two therapeutic agents, ATRA and arsenic trioxide (ATO), induce differentiation of promyelocytes in vivo resulting in complete remission. However, some patients still relapse after ATO-ATRA based treatments and the mechanisms associated with resistance to these agents are still poorly understood.
Aims
The evaluation of the mutational spectrum of APL both at initial diagnosis and relapse.
Methods
We analyzed a cohort of 124 de novo APL cases including 14 cases who showed hematologic or molecular relapse. All patients (pts) were proven to have t(15;17)(q22;q12)/PML-RARA by chromosome banding analysis (CBA) (n=114), fluorescence in situ hybridization (n=120) and/or RT-PCR (n=124). 69 pts were male and 55 pts were female with a median age of 47 years (range: 16-84 years). All 124 samples were analyzed by next generation sequencing (NGS) using a 24-gene panel targeting ASXL1, CBL, CSF3R, DNMT3A, ETNK1, ETV6, EZH2, FLT3-TKD, GATA2, IDH1, IDH2, KIT, KRAS, NPM1, NRAS, RUNX1, SETBP1, SF3B1, SRSF2, TET2, TP53, U2AF1, WT1 and ZRSR2. FLT3-ITD was analyzed by gene scan. Relapse samples were screened for mutations within the PML-RARA fusion transcript by direct Sanger sequencing.
Results
Using standard CBA, additional cytogenetic aberrations were observed in 44/114 pts (27%). The most frequent secondary chromosome aberration was +8 (14/44; 32%). Using NGS 77/124 pts (62%) had at least one mutation (mut) in addition to PML-RARA, 17/77 (22%) had ≥2 additional mut (maximum: four). Most common were mutations in FLT3 (FLT3-ITD: 47/124, 38%, FLT3-TKD: 15/124; 12%) and WT1 (13/124, 10%). Mutations in other genes (ASXL1, CBL, DNMT3A, ETV6, KRAS, NRAS, RUNX1, SF3B1 and TET2) were found in less than 10% of cases, respectively. Comparing the initial mutational pattern of pts who relapsed during the course of disease with those staying in molecular remission revealed no difference in concomitant molecular mutations. Solely the percentage of pts with concomitant mutations was higher in the relapse group (79% vs. 60%; n.s.). Survival analysis revealed no influence of concomitant mutations in individual genes on prognosis. Also the amount of additional mutations had no prognostic impact. In selected cases (n=14/124), we compared changes in the patterns of genetic lesions between initial diagnosis and relapse. In 8/14 (57%) pts the initial mutation pattern changed at relapse. Mutations gained at relapse were WT1 (2/14, 14%) followed by DNMT3A, ETV6, FLT3-TKD, RUNX1 and TP53 (each 1/14, 7%). Loss of mutations was observed in FLT3-TKD, WT1 (each 2/14, 14%) as well as in ASXL1, FLT3-ITD and NRAS (each 1/14, 7%). In 4/14 relapsed pts (29%), mutations within the PML-RARA fusion transcript were detected. In none of the cases these mutations were detectable at initial diagnosis and thus all were acquired mutations. Missense mutations in the ligand binding domain of RARA were detected in 3 relapsed pts (p.Arg272Gln, p.Arg276Trp and p.Ser287Leu). In one relapsed APL pt, a mutation in the B2 domain of PML was observed (p.Ala216His). All mutations occurred in post-ATRA-relapse.
Conclusion
1) 62% of APL cases carry additional molecular mutations. 2) The most frequent additional molecular mutation is FLT3-ITD (38%) followed by FLT3-TKD mutations (12%) and mutations in WT1 (10%). 3) In 57% of relapsed APL the molecular mutation pattern changes. 4) Acquired mutations within the PML-RARA fusion transcript are detected in 29% of relapsed APL patients.
Session topic: E-poster
Keyword(s): APL, Molecular markers, PML-RAR, Relapse
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