International Journal of Laboratory Hematology The Official journal of the International Society for Laboratory Hematology
ORIGINAL ARTICLE
INTERNAT IONAL JOURNAL OF LABORATO RY HEMATO LOGY
Overexpression of lymphoid enhancer-binding factor-1 (LEF1) is a novel favorable prognostic factor in childhood acute lymphoblastic leukemia M. JIA, H.-Z. ZHAO, H.-P. SHEN, Y.-P. CHENG, Z.-B. LUO, S.-S. LI, J.-Y. ZHANG, Y.-M. TANG
Division of Hematology-oncology, Children’s Hospital of Zhejiang University School of Medicine, Key Laboratory of Reproductive Genetics (Zhejiang University), Ministry of Education, Hangzhou, China Correspondence: Yong-Min Tang, Division of Hematology-oncology, Children’s Hospital of Zhejiang University School of Medicine, Key Laboratory of Reproductive Genetics (Zhejiang University), Ministry of Education, Hangzhou 310003, China. Tel.: 86 571 88873450; Fax: 86 571 87033296; E-mail: [email protected]
Ming Jia and Hai-Zhao Zhao contributed equally to this work and should be considered as co-first authors. doi:10.1111/ijlh.12375
Received 8 February 2015; accepted for publication 26 March 2015
S U M M A RY Introduction: Lymphoid enhancer-binding factor-1 (LEF1) is a target gene and central mediator of the Wnt signaling pathway. High LEF1 expression has been reported as a prognostic marker in several types of hematologic malignancies of adult patients. Methods: In this study, LEF1 expression was analyzed by real-time polymerase chain reaction (PCR) in 122 children with newly diagnosed ALL treated on the China NPCAC97 protocols. Patients’ samples were dichotomized at the median value of control group and divided into LEF1low and LEF1high groups. Results: The LEF1 mRNA levels in patients with ALL were significantly higher than those of normal controls, and the LEF1 levels were dramatically decreased following induction therapy. In addition, LEF1high patients had lower white blood cell (WBC) count at diagnosis and lower minimal residual disease (MRD) levels at the time of complete remission as compared to LEF1low patients. Finally, our studies showed that high LEF1 expression is associated with favorable CR rate and overall survival (OS) in childhood ALL (5-year OS: LEF1high 92% vs. LEF1low 73%, P = 0.009). High LEF1 level was associated with a favorable relapse-free survival in standard-risk patients and also related to a better OS within the subgroup of patients with BCR-ABL-negative ALL. Conclusion: Overexpression of LEF1 is a favorable prognostic factor in childhood ALL. The prognostic impact of LEF1 may assist treatment stratification and suggest the need of alternative regimens.
Keywords LEF1, acute lymphoblastic leukemia, childhood, prognosis, overall survival
© 2015 John Wiley & Sons Ltd, Int. Jnl. Lab. Hem. 2015, 37, 631–640
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M. JIA ET AL. | LEF1 EXPRESSION IN ACUTE LYMPHOBLASTIC LEUKEMIA
INTRODUCTION Acute lymphoblastic leukemia (ALL) is the most common malignancy in children. Great success has been achieved in the treatment of pediatric ALL, which has led to the cure of approximately 80% of children on most current treatment protocols [1]. However, approximately 20% of children with ALL still suffer from relapse. Among them, more than half of the children contemporary therapies failed were initially classified as nonhigh risk, highlighting the need for improved prognostic markers [2]. Today, several clinical and genetic factors are routinely used to stratify patients into different risk groups, such as age, white blood cell (WBC) count, minimal residual disease (MRD), and genetic features [3–7]. Gene expression signatures have been constructed and proposed as new prognostic markers in treatment protocols [8–12]. Aberrations of some genes which can predict prognosis and provide possible therapeutic targets in future for childhood patients with ALL have been found, such as deletion of IKZF1 [13–16] and CRLF2 gene alterations [17–19]. However, childhood ALL is also a disorder with clinical and biological heterogeneity. Therefore, it is always a topic of interest to find more biological markers to optimize the classification and improve the initial risk assessment of childhood ALL, so as to offer guidance for appropriate treatment. Lymphoid enhancer-binding factor-1 (LEF1) is a member of the LEF/T-cell factor family of transcription factors and a key mediator of the canonical Wingless-type (Wnt) pathway [20]. It mediates Wnt signals through recruiting b-catenin and its co-activators to Wnt response elements of target genes and plays crucial roles during development, including normal hematopoiesis [21]. LEF1 has been shown to function in vivo as either an oncogene or a tumor suppressor in different cellular contexts. Transplantation of LEF1-transduced bone marrow leads to acute myeloid leukemia and B-precursor ALL in mouse models [22]. In normal hematopoiesis, LEF1 plays a crucial role not only in the development of B and T lymphocytes but also in granulopoiesis. Recently, increased LEF1 level has been reported as a favorable prognostic marker in cytogenetically normal AML (CN-AML) [23, 24]. However, several investigations have indicated that high level of LEF1 predicts an adverse
outcome in adult B-precursor acute lymphoblastic leukemia [25] and in chronic lymphocytic leukemia [26]. In contrast, few studies have been reported on the prognostic value of LEF1 expression in childhood ALL so far. To test this, we analyzed LEF1 mRNA expression levels in 122 childhood patients with newly diagnosed ALL and investigated their correlation with clinical outcomes.
M AT E R I A L S A N D M E T H O D S Patients and treatment Gene expression studies for LEF1 were retrospectively performed in 122 patients (45 females, 77 males; median age 6 years, range 1–14 years) with newly diagnosed pediatric ALL and 30 healthy volunteers as a control between January 2007 and December 2010 at the Children’s Hospital of Zhejiang University School of Medicine. Clinical and molecular features and outcome of our study cohort were comparable with those from the total study population. Diagnosis of ALL was confirmed by morphological, immunological, cytogenetic, and molecular characterization in central laboratories of the hospital. Bone marrow (BM) samples from seventeen patients also were collected during the first CR. Written informed consents were obtained from patients’ parents. All treatments were administered in accordance with the Declaration of Helsinki and approved by the institutional local review board of ethnics. Among this cohort, 94 patients had been newly diagnosed with B-cell ALL and 28 patients with T-cell ALL. Disease was classified as high risk (HR) if a patient had any one of the following features: (i) age
ORIGINAL ARTICLE
INTERNAT IONAL JOURNAL OF LABORATO RY HEMATO LOGY
Overexpression of lymphoid enhancer-binding factor-1 (LEF1) is a novel favorable prognostic factor in childhood acute lymphoblastic leukemia M. JIA, H.-Z. ZHAO, H.-P. SHEN, Y.-P. CHENG, Z.-B. LUO, S.-S. LI, J.-Y. ZHANG, Y.-M. TANG
Division of Hematology-oncology, Children’s Hospital of Zhejiang University School of Medicine, Key Laboratory of Reproductive Genetics (Zhejiang University), Ministry of Education, Hangzhou, China Correspondence: Yong-Min Tang, Division of Hematology-oncology, Children’s Hospital of Zhejiang University School of Medicine, Key Laboratory of Reproductive Genetics (Zhejiang University), Ministry of Education, Hangzhou 310003, China. Tel.: 86 571 88873450; Fax: 86 571 87033296; E-mail: [email protected]
Ming Jia and Hai-Zhao Zhao contributed equally to this work and should be considered as co-first authors. doi:10.1111/ijlh.12375
Received 8 February 2015; accepted for publication 26 March 2015
S U M M A RY Introduction: Lymphoid enhancer-binding factor-1 (LEF1) is a target gene and central mediator of the Wnt signaling pathway. High LEF1 expression has been reported as a prognostic marker in several types of hematologic malignancies of adult patients. Methods: In this study, LEF1 expression was analyzed by real-time polymerase chain reaction (PCR) in 122 children with newly diagnosed ALL treated on the China NPCAC97 protocols. Patients’ samples were dichotomized at the median value of control group and divided into LEF1low and LEF1high groups. Results: The LEF1 mRNA levels in patients with ALL were significantly higher than those of normal controls, and the LEF1 levels were dramatically decreased following induction therapy. In addition, LEF1high patients had lower white blood cell (WBC) count at diagnosis and lower minimal residual disease (MRD) levels at the time of complete remission as compared to LEF1low patients. Finally, our studies showed that high LEF1 expression is associated with favorable CR rate and overall survival (OS) in childhood ALL (5-year OS: LEF1high 92% vs. LEF1low 73%, P = 0.009). High LEF1 level was associated with a favorable relapse-free survival in standard-risk patients and also related to a better OS within the subgroup of patients with BCR-ABL-negative ALL. Conclusion: Overexpression of LEF1 is a favorable prognostic factor in childhood ALL. The prognostic impact of LEF1 may assist treatment stratification and suggest the need of alternative regimens.
Keywords LEF1, acute lymphoblastic leukemia, childhood, prognosis, overall survival
© 2015 John Wiley & Sons Ltd, Int. Jnl. Lab. Hem. 2015, 37, 631–640
631
632
M. JIA ET AL. | LEF1 EXPRESSION IN ACUTE LYMPHOBLASTIC LEUKEMIA
INTRODUCTION Acute lymphoblastic leukemia (ALL) is the most common malignancy in children. Great success has been achieved in the treatment of pediatric ALL, which has led to the cure of approximately 80% of children on most current treatment protocols [1]. However, approximately 20% of children with ALL still suffer from relapse. Among them, more than half of the children contemporary therapies failed were initially classified as nonhigh risk, highlighting the need for improved prognostic markers [2]. Today, several clinical and genetic factors are routinely used to stratify patients into different risk groups, such as age, white blood cell (WBC) count, minimal residual disease (MRD), and genetic features [3–7]. Gene expression signatures have been constructed and proposed as new prognostic markers in treatment protocols [8–12]. Aberrations of some genes which can predict prognosis and provide possible therapeutic targets in future for childhood patients with ALL have been found, such as deletion of IKZF1 [13–16] and CRLF2 gene alterations [17–19]. However, childhood ALL is also a disorder with clinical and biological heterogeneity. Therefore, it is always a topic of interest to find more biological markers to optimize the classification and improve the initial risk assessment of childhood ALL, so as to offer guidance for appropriate treatment. Lymphoid enhancer-binding factor-1 (LEF1) is a member of the LEF/T-cell factor family of transcription factors and a key mediator of the canonical Wingless-type (Wnt) pathway [20]. It mediates Wnt signals through recruiting b-catenin and its co-activators to Wnt response elements of target genes and plays crucial roles during development, including normal hematopoiesis [21]. LEF1 has been shown to function in vivo as either an oncogene or a tumor suppressor in different cellular contexts. Transplantation of LEF1-transduced bone marrow leads to acute myeloid leukemia and B-precursor ALL in mouse models [22]. In normal hematopoiesis, LEF1 plays a crucial role not only in the development of B and T lymphocytes but also in granulopoiesis. Recently, increased LEF1 level has been reported as a favorable prognostic marker in cytogenetically normal AML (CN-AML) [23, 24]. However, several investigations have indicated that high level of LEF1 predicts an adverse
outcome in adult B-precursor acute lymphoblastic leukemia [25] and in chronic lymphocytic leukemia [26]. In contrast, few studies have been reported on the prognostic value of LEF1 expression in childhood ALL so far. To test this, we analyzed LEF1 mRNA expression levels in 122 childhood patients with newly diagnosed ALL and investigated their correlation with clinical outcomes.
M AT E R I A L S A N D M E T H O D S Patients and treatment Gene expression studies for LEF1 were retrospectively performed in 122 patients (45 females, 77 males; median age 6 years, range 1–14 years) with newly diagnosed pediatric ALL and 30 healthy volunteers as a control between January 2007 and December 2010 at the Children’s Hospital of Zhejiang University School of Medicine. Clinical and molecular features and outcome of our study cohort were comparable with those from the total study population. Diagnosis of ALL was confirmed by morphological, immunological, cytogenetic, and molecular characterization in central laboratories of the hospital. Bone marrow (BM) samples from seventeen patients also were collected during the first CR. Written informed consents were obtained from patients’ parents. All treatments were administered in accordance with the Declaration of Helsinki and approved by the institutional local review board of ethnics. Among this cohort, 94 patients had been newly diagnosed with B-cell ALL and 28 patients with T-cell ALL. Disease was classified as high risk (HR) if a patient had any one of the following features: (i) age
