Does TAL-1 deletion contribute to the high incidence of T-cell acute lymphoblastic leukemia in South Indian patients?

Asian Pac J Cancer Prev. 2008 Jan-Mar;9(1):127-30.


Background: The incidence of T-cell acute lymphoblastic leukemia (T-ALL) in South India is very high (43.1%) when compared to the Western countries (10-20%). TAL-1 deletion is the most common genetic abnormality in T-ALL.

Objectives: The present study was aimed to detect the incidence of type 1 and type 2 TAL-1 deletions and assess whether they might contribute to the high incidence of T-ALL in South India.

Materials and methods: 45 cases of T-ALL (pediatric-32, adolescents-7 and young adults-6) were studied by DNA-PCR and sequencing. Age of the patients ranged from 3 yrs to 29 yrs (median age 14 yrs).

Results: TAL-1 deletion type 1 was detected in 6 (13.3%) cases (3 pediatric and 3 adolescents) and all were males. TAL-1 deletion type 2 was not present. Comparing the clinical features and immunological marker analysis of TAL-1 deletion positive and negative cases did not show any significant differences except in the WBC count, which was significantly higher in cases showing TAL-1 deletion (>100 x 109/L, p value= 0.003). All the positive cases of TAL-1 deletion were confirmed by sequencing, the results showing that the fusion region at SIL gene and TAL-1 gene contained an average 'N region' insertion of 7.8 nucleotides. The numbers of nucleotides deleted at the 5' end and 3' end of TAL-1 gene were averages of 3 and 1, respectively.

Conclusion: Though the incidence of T-ALL is high in South India, the frequency of TAL-1 deletion and their fusion gene sequences are not unique and are similar to those reported in other ethnic and geographic populations. Hence the present study indicates that TAL-1 deletion alone does not contribute to the high incidence of T-ALL in South Indian patients.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Basic Helix-Loop-Helix Transcription Factors / genetics*
  • Child
  • Child, Preschool
  • Female
  • Humans
  • Incidence
  • India / epidemiology
  • Male
  • Polymerase Chain Reaction
  • Precursor T-Cell Lymphoblastic Leukemia-Lymphoma / diagnosis
  • Precursor T-Cell Lymphoblastic Leukemia-Lymphoma / epidemiology
  • Precursor T-Cell Lymphoblastic Leukemia-Lymphoma / genetics*
  • Proto-Oncogene Proteins / genetics*
  • Sequence Deletion
  • T-Cell Acute Lymphocytic Leukemia Protein 1
  • Young Adult


  • Basic Helix-Loop-Helix Transcription Factors
  • Proto-Oncogene Proteins
  • T-Cell Acute Lymphocytic Leukemia Protein 1
  • TAL1 protein, human