Sorted By Test Name - Mayo Medical Laboratories

CD40
89009
conventional cytogenetic studies, and at least 36 chromosome anomalies are common in this disorder.(1)
The most common karyotype among children with ALL is hyperdiploidy, which is associated with a good
prognosis in the absence of any structural anomalies and when associated with trisomies of chromosomes
4, 10, and 17. The most common chromosome translocations in pediatric ALL include t(9;22)(q34;q11.2),
t(12;21)(p13;q22), t(1;19)(q23;p13), t(8;14)(q24;q32), t(14;var)(q32;var), and t(11;var)(q23;var). The
t(12;21)(p13;q22) is associated with ETV6/RUNX1 fusion and is impossible to detect by conventional
cytogenetic studies. This translocation, along with other common translocations, can be successfully
detected by FISH. All of these translocations are important to detect as they are critical prognostic
markers. The decision for early transplantation may be made if t(9;22)(q34;q11.2) is detected. In contrast,
if t(12;21)(p13;q22) or ETV6/RUNX1 fusion is detected, the patient has an excellent prognosis and
transplantation is rarely considered. Deletions of chromosome 9 p-arm are also common, though the
clinical significance of this finding is still uncertain. Cytogenetic and/or FISH testing is critical in the
workup of patients with ALL to ensure the most appropriate treatment.(2) We recommend the following
testing for patients with ALL(1): -At diagnosis, conventional cytogenetic studies (eg, BM/8506
Chromosome Analysis, Hematologic Disorders, Bone Marrow) should be performed, especially for
pediatric individuals, where solely numeric anomalies occur in 25% of patients. -FISH is valuable in some
cases to detect certain cryptic chromosome anomalies such as ETV6/RUNX1 fusion associated with
t(12;21)(p12;q22). -FISH studies should be done at diagnosis whenever results of chromosome studies do
not demonstrate a classical chromosome anomaly (ie, chromosome studies are normal or complex); FISH
studies should also be considered when results of chromosome studies are unsuccessful. -FISH can be
performed at diagnosis and after treatment to establish a benchmark for the percentage of neoplastic cells
to help assess the effectiveness of therapy. -If the patient relapses, a conventional chromosome study is
useful to identify prognostic changes in the neoplastic clone and identify any newly arisen clones.
Useful For: As an adjunct to conventional chromosome studies in patients with acute lymphoblastic
leukemia (ALL), especially: -When conventional chromosome studies do not demonstrate a classic
chromosome anomaly -For pediatric patients -When results for conventional chromosome studies are
normal or unavailable because of an unsuccessful study Detecting clones with t(1;19), t(9;22), t(12;21),
t(11;var), t(14;var), del(9p), +4, +10, or +17 Quantifying disease before and after treatment for patients
with ALL Assessing residual disease after treatment (in this situation, it is cost effective to order only
those FISH probes that produced abnormal results prior to treatment)
Interpretation: An interpretive report is provided. A neoplastic clone is detected when the percent of
cells with any given chromosome abnormality exceeds the normal cutoff. This method detects neoplastic
clones with chromosome abnormalities in more than 80% of patients with acute lymphoblastic leukemia.
Disease can be quantified by determining the percentage of cells demonstrating anomalies. The effect of
treatment can be assessed by comparing the percentage of cells demonstrating anomalies before and after
therapy.
Reference Values:
An interpretive report will be provided.
Clinical References: 1. Dewald GW, Ketterling RP: Conventional cytogenetics and molecular
cytogenetics in hematological malignancies. In Hematology. Basic Principles and Practice. 4th edition.
Edited by R Hoffman, E Benz, S Shattil, et al. Philadelphia, Churchill Livingston, 2005, pp 928-939 2.
Pui CH, Relling MV, Downing JR: Acute lymphoblastic leukemia. N Engl J Med 2004
Apr;350(15):1535-1548
B-Cell CD40 Expression by Flow Cytometry, Blood
Clinical Information: The adaptive immune response includes both cell-mediated (mediated by T
cells and natural killer [NK] cells) and humoral (mediated by B cells) immunity. After antigen recognition
and maturation in secondary lymphoid organs, some antigen-specific B cells terminally differentiate into
antibody-secreting plasma cells. Decreased numbers or aberrant function of B cells result in humoral
immune deficiency states with increased susceptibility to infections, and these may be either primary
(genetic) or secondary immunodeficiencies. Secondary causes include medications, malignancies,
infections, and autoimmune disorders (this does not cause immunodeficiency with increased infection).
CD40 is a member of the tumor necrosis factor receptor superfamily, expressed on a wide range of cell
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