B-cell and T-cell acute lymphoblastic leukemia

Individualized test options for each patient

In the United States, the incidence of acute lymphoblastic leukemia (ALL) is approximately 1 in 50,000. ALL accounts for approximately 70% of all childhood leukemia cases (ages 0 to 19 years), making it the most common type of childhood cancer. Approximately 85% of pediatric cases of ALL are B-cell lineage (B-ALL) and 15% are T-cell lineage (T-ALL). It has a peak incidence at 2 to 5 years of age. The incidence decreases with increasing age, before increasing again at around 50 years of age. 

A combination of cytogenetic and FISH testing is currently recommended in all pediatric and adult patients to characterize the B-ALL and T-ALL clones for the prognostic genetic subgroups. Each of the genetic subgroups are important to detect, can be critical prognostic markers, and also can assist in treatment selection. 

A newly recognized World Health Organization (WHO) entity BCR-ABL1-like ALL, also known as Philadelphia chromosome-like acute lymphoblastic leukemia (Ph-like ALL), is increasing in importance due to the poor prognosis seen in pediatric, adolescent, and young adult ALL. Common features of this entity involve rearrangements with tyrosine kinase genes involving the following genes: ABL2, PDGFRB, JAK2, ABL1, CRLF2, P2RY8, and deletions involving IKZF1. Patients who have failed conventional therapies have demonstrated favorable responses to targeted therapies when rearrangements involving these specific gene regions have been identified.

Mayo Clinic offers a large FISH menu to meet the needs of individual patients including B-ALL, T-ALL, and Ph-like focused FISH panels as well as individual probes for patient monitoring.

Common chromosome abnormalities in
B-acute lymphoblastic leukemia

Common chromosome abnormalities in
T-cell acute lymphoblastic leukemia

Which test should I order?

A Test in Focus

Horatiu Olteanu, M.D., Ph.D., gives an overview of the new T-cell receptor (TCR) β-chain constant region (TRBC1) flow cytometry marker, which is now included in Mayo Clinic Laboratories' routine diagnostic T-cell flow cytometry panel. He discusses when this testing should be ordered, how the addition of TCRBC1 compares to previous testing approaches, and how this marker can assist ordering physicians.

Learn more about how to order these evaluations at your institution.