SMYD2 is highly expressed in pediatric acute lymphoblastic leukemia and constitutes a bad prognostic factor

Acute lymphoblastic leukemia (ALL) is the most common childhood malignancy. Although several clinical characteristics can be associated with worse prognosis, more robust biological markers still remains uncovered. SMYD2, a member of SMYD protein family, regulates the activity of several proteins through methylation. In this study, we performed quantitative real time PCR to compare the expression of SMYD2 in 83 pediatric ALL patients and non-neoplastic bone marrow samples (BMS). The study revealed that SMYD2 expression is altered in ALL BMS and its high expression was correlated with a bad prognosis. Moreover, we also revealed that SMYD2 expression level significantly decreases in patients that respond to chemotherapy treatment.

Genetic aberrations in paediatric acute leukaemias and implications for management of patients

The process of malignant transformation in paediatric acute leukaemias is complex, requiring at least two deleterious events resulting in DNA damage. This damage ranges from point-mutations to double-strand DNA breaks leading to various types of chromosomal rearrangements. In this review we summarise the most common genetic aberrations for the three main subtypes of paediatric acute leukaemia: B-cell-precursor acute lymphoblastic leukaemia, T-cell acute lymphoblastic leukaemia and acute myeloid leukaemia. Several genetic aberrations are independent prognostic factors, and are now used in risk stratification for treatment. Molecular pathways activated by genetic aberrations could provide potential molecular targets for novel therapies. Some genetic aberrations represent sensitive targets for molecular detection of minimal residual disease. This provides hope for the development of targeted therapies, effective against leukaemic cells.

Where can biology of childhood ALL be attacked by new compounds?

Although the majority of children with acute lymphoblastic leukemia (ALL) can be cured with combination chemotherapy, the challenge remains to salvage patients with resistant disease and to reduce treatment related toxicity. To meet this challenge, it will be essential to incorporate new agents targeting the biological Achilles Heels of this cancer more rapidly into currently available treatment regimen. Here we review the principles of current ALL therapy, recent advances in understanding ALL biology and discuss a selection of promising areas for drug development that may take advantage of the underlying leukemia biology. We focus particularly on strategies to interfere with common effector mechanisms that can be trigged by different individual oncogenic lesions and on new agents from drug development programs in adult oncology, as such agents will come with better chances for sustainable commercial development.

Allogeneic hematopoietic cell transplantation (allogeneic HCT) for treatment of pediatric Philadelphia chromosome-positive acute lymphoblastic leukemia (ALL)

BACKGROUND

Allogeneic hematopoietic cell transplant (HCT) with best available donor for children with Philadelphia positive (Ph+) acute lymphoblastic leukemia (ALL) has previously been considered standard practice. Since the introduction of imatinib into the treatment of this disease, the role of allogeneic HCT is more uncertain.

PROCEDURE

We investigated the impact of remission status, graft source, and imatinib use on transplant outcomes for 37 children with Ph+ ALL who received an allogeneic HCT at the University of Minnesota between 1990 and 2006. The median age at HCT was 7.47 (range; 1.4-16.4) years. Thirteen patients received imatinib therapy pre- and/or post-HCT (imatinib group) and 24 patients, received either no imatinib (n = 23) or only post-HCT relapse (n = 1) (non-imatinib group).

RESULTS

There was no difference in disease-free survival (DFS) or relapse between the imatinib and non-imatinib groups at 3 years (62%/15% vs. 53%/26%; P = 0.99; 0.81, respectively). There was no significant difference in transplant outcomes between matched related donor or unrelated donor (umbilical cord blood or matched unrelated marrow) recipients whereas patients receiving allogeneic HCT in first remission (CR1) had superior DFS and less relapse compared to patients transplanted in >or=CR2 (71%/16% vs. 29%/36%; P = 0.01; P = 0.05).

CONCLUSIONS

Based on this retrospective analysis at a single institution, the use of imatinib either pre- and/or post-transplant does not appear to significantly impact outcomes for children with Ph+ ALL and allogeneic HCT with the best available donor should be encouraged in CR1.

The treatment of pediatric Philadelphia positive (Ph+) leukemias in the imatinib era

BACKGROUND

As the treatment of Philadelphia positive (Ph+) leukemias in the era of imatinib continues to evolve, the role of allogeneic hematopoietic cell transplantation (allogeneic-HCT) in first remission is becoming more unclear.

PROCEDURE

Thirty-two pediatric centers across the United States and Canada were surveyed regarding current treatment practices for Ph+ acute lymphoblastic leukemia (ALL) and chronic myelogenous leukemia (CML). The survey addressed treatment approaches for Ph+ ALL and CML in terms of imatinib therapy and use of allogeneic-HCT.

RESULTS

Twenty-three of the 32 centers returned the survey to provide a 72% response rate. Of the 27 physicians responding to the survey, 22 (81%) recommended a matched sibling donor (MSD) allogeneic-HCT, when available, in first remission for Ph+ ALL compared to 17/27 (63%) for patients with first chronic phase CML. There was universal agreement among survey responders regarding the use of imatinib upfront in Ph+ ALL and CML patients while 13 of 27 (48%) physicians reported using imatinib as maintenance therapy post-HCT for Ph+ ALL compared to 9 of 27 (33%) for CML.

CONCLUSIONS

Although a treatment consensus did not exist based on the results of this small survey, current treatment practices for pediatric Ph+ ALL and CML appear to favor allogeneic-HCT when a MSD is available. The use of post-HCT imatinib as maintenance therapy to avoid relapse for either Ph+ ALL or CML remains uncertain and awaits future prospective studies.

Impact of tyrosine kinase inhibitors on patient outcomes in Philadelphia chromosome-positive acute lymphoblastic leukaemia

Acute lymphoblastic leukaemia (ALL) is a heterogeneous disease that is often associated with several chromosomal and molecular abnormalities. Patients who have the Philadelphia (Ph) chromosome and associated BCR-ABL1 oncogene have a particularly poor prognosis. Currently, allogeneic haematopoietic stem cell transplantation (allo-HSCT) is the only known curative treatment for Ph+ ALL and facilitating allo-HSCT in eligible patients is a key treatment goal. However, many patients relapse after allo-HSCT, particularly those with measurable residual disease prior to transplantation, and a significant percentage of patients are ineligible for allo-HSCT, particularly older patients. Hence, many patients require additional/alternative therapies to prolong survival. Studies are ongoing to determine the most effective first-line drug regimens for patients who subsequently undergo allo-HSCT and ineligible patients. Tyrosine kinase inhibitors targeted to Bcr-Abl are important novel therapies for Ph+ ALL. Although imatinib administered in combination with chemotherapy is established as the current first-line strategy, relapse is common, even among allo-HSCT recipients. Emerging data indicate that more potent multi-targeted kinase inhibitors (including dasatinib, nilotinib, and bosutinib) have promising efficacy in the first- or second-line setting. Here, the evidence base for existing drug treatments for Ph+ ALL is discussed and emerging therapeutic strategies are explored.

Impact of age, leukocyte count and day 21-bone marrow response to chemotherapy on the long-term outcome of children with philadelphia chromosome-positive acute lymphoblastic leukemia in the pre-imatinib era: results of the FRALLE 93 study

BACKGROUND

We explored the heterogeneity of philadelphia chromosome-positive acute lymphoblastic leukemia (Ph1-ALL) in a study of the effect of early features on prognosis in children. Here we report the long-term results of the FRALLE 93 study conducted in the era before the use of tyrosine kinase inhibitors.

METHODS

Between 1993 and 1999, 36 children with Ph1-ALL were enrolled into the FRALLE 93 protocol. After conventional four-drug induction, children were stratified by availability of an HLA-matched sibling.

RESULTS

Complete remission (CR) was observed in 26 children (72%), of which 13 underwent allogeneic bone marrow transplantation (BMT). Thirty-one children were good responders to prednisone, defined on day 8, and 21 were good responders to chemotherapy, defined by day-21 bone marrow (M1). Overall five-year disease-free survival (DFS) was 42 +/- 9.7%. Based on multivariate analysis, two groups showed marked differences in five-year outcome: children with age<10, leukocyte count <100,000/mm3 and day-21 M1 marrow had a more favorable prognosis (14 pts: 100% CR, event free survival [EFS]: 57%, overall survival [OS]: 79%), than the high-risk group (22 patients: 55% CR, EFS: 18%, OS: 27%) (p < 0.005). We also observed a non statistically significant difference (p = 0.14) in outcome between these groups for transplanted patients (5-year DFS: 83 +/- 14% and 33 +/- 15%, respectively).

CONCLUSION

Age, leukocyte count and early response to treatment defined by the D21 bone marrow response provide an accurate model for outcome prediction. The combination of available tools such as minimal residual disease assessment with determination of these simple factors could be useful for refining indications for BMT in the current era of tyrosine-kinase inhibitor-based therapy.