An analysis of leukemic cell chromosomal features in infants

Area of Science:

• Pediatric Oncology
• Cytogenetics
• Hematology

Background:

• Infant leukemia presents unique diagnostic and prognostic challenges.
• Chromosomal abnormalities are common in childhood leukemias but vary in incidence and type in infants.

Purpose of the Study:

• To analyze chromosomal findings in a cohort of 27 infants diagnosed with leukemia.
• To identify nonrandom chromosomal abnormalities and their correlation with leukemia subtypes and phenotypes in infants.

Main Methods:

• Karyotypic analysis of leukemic cells from 27 infants.
• Classification of leukemia into acute lymphoblastic leukemia (ALL) and acute nonlymphoblastic leukemia (ANLL) subtypes.
• Phenotypic analysis including common ALL antigen (CALLA) and cytoplasmic immunoglobulin.

Main Results:

• 25 out of 27 infants (93%) exhibited abnormal karyotypes, with 21 (84%) being pseudodiploid.
• Chromosomal translocations were observed in 67% of ANLL and 78% of ALL cases.
• Recurrent abnormalities included t(9;11)(p21-22;q23) in monocytic leukemia, inv(16) in myelomonocytic leukemia, and t(4;11)(q21;q23) in ALL. The 11q23-25 region was frequently involved.

Conclusions:

• Infant leukemia is characterized by a high frequency of chromosomal abnormalities, including specific translocations.
• The presence of CALLA- or pre-B phenotype and chromosomal translocations in ALL may contribute to the poor prognosis observed in infants.
• The frequent involvement of the 11q23-25 region suggests a potential pathogenetic role in infant leukemia.