Clinical features, laboratory characteristics, and outcome of ETP and TCRA/D aberrations in pediatric patients with T-acute lymphoblastic leukemia

BACKGROUND

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive malignancy with few accepted prognostic factors that limit the efficiency of therapy. The aim of the current study was to assess the clinical and laboratory features of T-cell receptor (TCR) aberrations and early T-cell precursor (ETP) subtype as well as their outcome to therapy.

METHODS

Sixty-three newly diagnosed pediatric T-ALL patients were assessed for the ETP status using immunophenotyping. Screening of TCRA/D aberrations was done by fluorescent in situ hybridization (FISH). The data were correlated to the patients' clinical features, response to treatment, and survival rates.

RESULTS

Seven patients (11%) had ETP-ALL. The ETP-ALL patients were older (P = 0.013), presented with lower white blood cell (WBC) count (P = 0.001) and lower percentage of peripheral blood (PB) blast cells (P = 0.037), more likely to have hyperdiploid karyotype (P = 0.009), and had been associated with TCRA/D gene amplification (P = 0.014) compared to other T-ALL patients. Of note, the same associations had been significantly observed in patients with TCRA/D gene amplification. Patients with TCRA/D amplification frequently coincided with TCRβ aberrations (P = 0.025). TCR-β aberrations were significantly associated with negative MRD at the end of induction compared to TCR-β-negative patients. There was a nonsignificant trend of ETP-positive cases to have lower overall survival (OS) (P = 0.06). Patients with TCR aberrations had no significant differences regarding disease-free survival (DFS) or OS rates compared to those with normal TCR.

CONCLUSION

ETP-ALL patients tend to have increased mortalities. There was no significant impact of TCR aberrations on the survival rates of the patients.

Early T-cell precursor acute lymphoblastic leukemia and other subtypes: a retrospective case report from a single pediatric center in China

PURPOSE

Early T-cell precursor acute lymphoblastic leukemia (ETP-ALL) is rare in China and case reports are varied. We conducted an in-depth analysis of newly diagnosed children with T-ALL from January 1999 to April 2015 in our center, to show the biological differences between Chinese ETP-ALL children and other immune types of T-ALL.

METHODS

The newly diagnosed children with T-ALL were divided into four groups according to their immunophenotype: ETP-ALL, early non-ETP-ALL, cortical T-ALL and medullary T-ALL. Disease-free survival (DFS), event-free survival (EFS), and overall survival (OS) rates were estimated by the Kaplan-Meier method. The Cox regression model was used for multivariate analysis.

RESULTS

A total of 117 newly diagnosed children with T-ALL were enrolled in this study. The 10-year EFS and OS rates for all patients were 59.0 ± 4.7% and 61.0 ± 4.7%, respectively, with a median follow-up of 64 (5-167) months. Univariate analysis showed that ETP-ALL patients had the lowest 10-year DFS rate of 32.1 ± 11.7%, while cortical T-ALL had the highest DFS rate of 81.3 ± 8.5% compared with early non-ETP-ALL (61.6 ± 7.0%) and medullary T-ALL (59.1 ± 10.6%). Multivariate analysis demonstrated that only ETP-ALL and involvement of the central nervous system were independent prognostic factors.

CONCLUSION

Compared with other subtypes, pediatric ETP-ALL had a poor treatment response and high recurrence rate while cortical T-ALL appeared to have much better outcome. Our observations highlight the need for an individualized treatment regime for ETP-ALL.

T-lymphoblastic leukemia/lymphoma

OBJECTIVES

To review important concepts from the 2013 Society for Hematopathology/European Association for Haematopathology Workshop session on T-acute lymphoblastic leukemia/T-lymphoblastic lymphoma (T-ALL/T-LBL).

METHODS

Twenty-one submitted cases are reviewed and summarized, with emphasis on key diagnostic or biologic points, and supplemented with relevant literature citations.

RESULTS

Early T-cell precursor (ETP)-ALL represented about one-third of all cases submitted. It is important to recognize ETP-ALL, because these patients have a poor prognosis if treated with standard therapy. A consensus immunophenotype has been developed to aid in the recognition of these cases. Other cases submitted illustrated rare entities, including two cases of Philadelphia chromosome-positive T-ALL, two cases of T-ALL associated with MYC translocations, and single cases illustrating various diseases. A subset of cases submitted illustrated issues related to differential diagnosis of T-ALL/T-LBL.

CONCLUSIONS

In view of the growing importance of molecular genetic analysis in the diagnosis and prognosis of T-ALL/T-LBL, it is important for pathologists to keep abreast of these developments. Currently, routine histopathology, immunophenotyping, conventional cytogenetic analysis, fluorescence in situ hybridization, and clonality testing are usually adequate to establish the diagnosis. However, as therapies become more targeted, assessment for relevant genetic abnormalities, either through candidate gene or broad-scale unbiased approaches, may become necessary.

Early T-cell Precursor Acute Lymphoblastic Leukemia/Lymphoma

Discrete diagnostic subtypes of T lymphoblastic leukemia/lymphoma (T-cell acute lymphoblastic leukemia/lymphoma, T-ALL) have historically not been widely recognized. Recently, a novel subset with distinctive immunophenotypic, molecular, and clinical features has been proposed. Termed early T-cell precursor acute lymphoblastic leukemia (ETP-ALL), these cases seem to correspond to a very early stage of T-cell development. ETP-ALL is associated with a poor prognosis using standard protocols, and patients with ETP-ALL may benefit from intensified, alternative, or targeted therapies. Recognizing ETP-ALL and distinguishing it from other forms of acute leukemia are important elements of an up-to-date diagnostic approach to precursor T-cell neoplasms.