Contributions
Abstract: EP478
Type: E-Poster Presentation
Session title: Acute myeloid leukemia - Clinical
Background
CD7 is a lymphoid marker that can be aberrantly expressed in Acute Myeloid Leukemia (AML). Several studies have investigated the significance of this marker in adult AML, but the significance is still unclear.
Aims
We investigated CD7 expression in newly diagnosed pediatric AML and correlated with clinical and genetic features and outcomes.
Methods
We retrospectively reviewed data from 55 pediatric patients diagnosed with de novo AML from January 2010 to December 2020. AML diagnosis was assessed according to World Health Organization (WHO) criteria. All patients were enrolled in the Italian Association of Pediatric Hematology Oncology (AIEOP) AML 2002/01 and AML 2013/01 protocol. They were risk stratified and treated according to their respectively assigned protocol.
Induction chemotherapy was similar for the two clinical trials, while consolidation was based on risk stratification (standard vs high) for the first protocol and on risk stratification (standard, intermediate and high) and donor availability in the second. Patients with Down Syndrome AML underwent specific treatment. One CD7+ patient initially with ALL features was treated on the AIEOP LLA 2000R protocol, then was treated with AML-directed protocol (IDA FLA) since they were refractory to first line.
Results
Patients, disease and transplant characteristics are summarized in the Table. Thirty-five (64%) and 20 (36%) patients presented with CD7- and CD7+AML, respectively, four CD7+AML patients were with Down Syndrome (p=0.006).
Eleven/20 (55%) and 17/35 (49%) were male and median age was 7 and 8 years, among the CD7- and CD7+ subgroups, respectively.
Twenty-three (66%) and 8 (40%) patients underwent Allogenic Hematopoietic Stem Cell Transplantation (allo-HSCT) in the CD7+ and CD7- subgroups.
Measurable Residual Disease (MRD) on day +33, +78 (first and second time-points) and before transplant was negative in 22 (63%), 23 (66%), 17 (74%) and 12 (60%), 13 (65%), 5 (62%) in CD7- and CD7+ subgroups, respectively. Cytogenetic abnormalities, usually associated to a favorable outcome such as t (8;21), inv (16) or t (16;16) were less frequent in CD7+ compared to CD7- subgroup (5% vs 29%; p=0.042). No difference in median OS was noted between the 2 subgroups as described in Table.
Conclusion
Aberrant expression of the lymphoid CD7 antigen is associated with pediatric Down Syndrome AML. In contrast to early T-cell precursor lymphoblastic leukemias, where the expression of a myeloid marker is predictive of a worse outcome, the expression of this lymphoid marker in myeloid leukemias was not correlated with prognosis in terms of response to treatment, MRD or transplant outcomes.
Keyword(s): AML, Children, Down Syndrome
Abstract: EP478
Type: E-Poster Presentation
Session title: Acute myeloid leukemia - Clinical
Background
CD7 is a lymphoid marker that can be aberrantly expressed in Acute Myeloid Leukemia (AML). Several studies have investigated the significance of this marker in adult AML, but the significance is still unclear.
Aims
We investigated CD7 expression in newly diagnosed pediatric AML and correlated with clinical and genetic features and outcomes.
Methods
We retrospectively reviewed data from 55 pediatric patients diagnosed with de novo AML from January 2010 to December 2020. AML diagnosis was assessed according to World Health Organization (WHO) criteria. All patients were enrolled in the Italian Association of Pediatric Hematology Oncology (AIEOP) AML 2002/01 and AML 2013/01 protocol. They were risk stratified and treated according to their respectively assigned protocol.
Induction chemotherapy was similar for the two clinical trials, while consolidation was based on risk stratification (standard vs high) for the first protocol and on risk stratification (standard, intermediate and high) and donor availability in the second. Patients with Down Syndrome AML underwent specific treatment. One CD7+ patient initially with ALL features was treated on the AIEOP LLA 2000R protocol, then was treated with AML-directed protocol (IDA FLA) since they were refractory to first line.
Results
Patients, disease and transplant characteristics are summarized in the Table. Thirty-five (64%) and 20 (36%) patients presented with CD7- and CD7+AML, respectively, four CD7+AML patients were with Down Syndrome (p=0.006).
Eleven/20 (55%) and 17/35 (49%) were male and median age was 7 and 8 years, among the CD7- and CD7+ subgroups, respectively.
Twenty-three (66%) and 8 (40%) patients underwent Allogenic Hematopoietic Stem Cell Transplantation (allo-HSCT) in the CD7+ and CD7- subgroups.
Measurable Residual Disease (MRD) on day +33, +78 (first and second time-points) and before transplant was negative in 22 (63%), 23 (66%), 17 (74%) and 12 (60%), 13 (65%), 5 (62%) in CD7- and CD7+ subgroups, respectively. Cytogenetic abnormalities, usually associated to a favorable outcome such as t (8;21), inv (16) or t (16;16) were less frequent in CD7+ compared to CD7- subgroup (5% vs 29%; p=0.042). No difference in median OS was noted between the 2 subgroups as described in Table.
Conclusion
Aberrant expression of the lymphoid CD7 antigen is associated with pediatric Down Syndrome AML. In contrast to early T-cell precursor lymphoblastic leukemias, where the expression of a myeloid marker is predictive of a worse outcome, the expression of this lymphoid marker in myeloid leukemias was not correlated with prognosis in terms of response to treatment, MRD or transplant outcomes.
Keyword(s): AML, Children, Down Syndrome