Test ID: COGTF    
T-Cell Acute Lymphoblastic Leukemia (T-ALL), Children's Oncology Group Enrollment Testing, FISH, Varies

Evaluation of pediatric bone marrow and peripheral blood specimens by FISH probe analysis for classic rearrangements and chromosomal copy number changes associated with T-cell acute lymphoblastic leukemia (T-ALL) in patients being considered for enrollment in Children's Oncology Group (COG) clinical trials and research protocols.

Cytogenetic testing is important for the diagnostic and prognostic classification of pediatric neoplasia and it is a critical element for the enrollment of children into clinical trials affiliated with the Children's Oncology Group (COG). For over 25 years, the Mayo Clinic Genomics Laboratory has served as one of a select number of laboratories in the United States approved by the COG for the conventional chromosome analysis and FISH analysis of pediatric bone marrow, peripheral blood, and tissue specimens. All enrollment-required elements of cytogenetic testing will be electronically submitted by the Mayo Clinic Genomics Laboratory within the guidelines of COG.

This test is only performed on specimens from pediatric patients who are candidates for enrollment in Children's Oncology Group clinical trials and research protocols.

We recommend the following testing algorithm for patients with T-cell acute lymphoblastic leukemia (T-ALL):

-At diagnosis, standard (diagnostic) T-ALL FISH panel and/or conventional chromosome studies COGBM / Chromosome Analysis, Hematologic Disorders, Children's Oncology Group Enrollment Testing, Bone Marrow should be performed. If there is limited specimen available, only the COGTF / T-Cell Acute Lymphoblastic Leukemia (T-ALL), Children's Oncology Group Enrollment Testing, FISH, Varies test will be performed.

Panel includes testing for the following abnormalities using the probes listed:

1p33 rearrangement, TAL1/STIL

t(5;14) TLX3/BCL11B

7q34 rearrangement, TRB

9p-, CDKN2A/D9Z1

t(9;22) or ABL1 amplification, BCR/ABL1

t(10;11), MLLT10/PICALM

11q23 rearrangement, MLL (KMT2A)

14q11.2 rearrangement, TRAD

17p-, TP53/D17Z1

When an MLL (KMT2A) rearrangement is identified, reflex testing will be performed to identify the translocation partner. Probes include identification of t(4;11)(q21;q23) AFF1/MLL, t(6;11)(q27;q23) MLLT4/MLL, t(9;11)(p22;q23) MLLT3/MLL, t(10;11)(p13;q23) MLLT10/MLL, t(11;19)(q23;p13.1) MLL/ELL or t(11;19)(q23;p13.3) MLL/MLLT1.

When a TRAD rearrangement is identified, reflex testing will be performed to identify the translocation partner. Probes include identification of t(8;14)(q24.1;q11.2) MYC/TRAD, t(10;14)(q24;q11.2) TLX1/TRAD, t(11;14)(p15;q11.2) LMO1/TRAD or t(11;14)(p13;q11.2) LMO2/TRAD.

When a TRB rearrangement is identified, reflex testing will be performed to identify the translocation partner. Probes include identification of t(7;10)(q34;q24) TRB/HOX11, t(7;11)(q34;p15) TRB/LMO1, t(7;11)(q34;p13) TRB/LMO2, or t(6;7)(q27;q34) TRB/MYB.

-If this test is ordered and the laboratory is informed that the patient is not on a COG protocol, this test will be canceled and automatically reordered by the laboratory as TALLF / T-Cell Acute Lymphoblastic Leukemia (T-ALL), FISH, Varies.

Fluorescence In Situ Hybridization (FISH)