t(1;19)(q21 or 23;p13)
The t(1;19) or the der(19) from the t(1;19) rearrangement is almost exclusively observed in pre-B cell acute lymphocytic leukemia (ALL) with FAB-L1 morphology.  The t(1;19) ALL does not usually show extreme leukocytosis and suggests a relatively poor patient prognosis.

t(4;11)(q21;q23)
The t(4;11) is almost exclusively observed in early B-cell acute lymphocytic leukemia (ALL-L2).  Most patients with the t(4;11) ALL are less than two years old and present with  an extremely elevated white blood cell count along with a high percentage of blasts and hepatospenomegaly.  It is not uncommon for the t(4;11) ALL to show a biphenotypic immunologic presentation and to develop additional chromosome abnormalities as the disease progresses or during relapse.  The prognosis of t(4;11) ALL patients has been reported to be poor.

del (6q)(multiple breakpoint)
Deletion of the chromosome 6 long arm (6q-) is almost exclusively observed in lymphoid disease, including non-Hodgkin’s lymphoma.  The 6q- is rarely observed in Hodgkin’s disease.  The 6q- is usually accompanied by other chromosome changes and has been reported to indicate a relatively poor patient prognosis.

del(9)(p21 or 22)
Loss of material from the chromosome short arm (9p-) or rearrangements involving the 9 short arm has been most frequently observed in T-cell “lymphomatous” acute lymphocytic leukemia (ALL).  Patients usually present with elevated white blood cell counts and enlargement of  lymph nodes and spleen.  del(9) patients have also been reported to have a relatively poor patient prognosis and frequently exhibit CNS involvement.

t(9;22)(q34;q11 or 12)
When found in ALL, the t(9;22) indicates an extremely poor patient prognosis, particularly if accompanied by monosomy 7.

Hyperdiploidy with 50+ chromosomes
The presence of 50+ chromosomes without chromosome rearrangements or other clinically significant chromosome changes (e.g. 5q- or -7), is usually observed in acute lymphocytic leukemia (ALL) and frequently present in young patients, ages 3-5 years old.  Hyperdiploidy of this type has been reported to suggest a relatively poor patient prognosis.  The presence of chromosome rearrangements generally suggests a prognosis relative to the type of rearrangement.

Near-haploidy with 26-29 chromosomes
Near-haploidy is a relatively rare and possibly under-reported finding usually observed in early B-cell acute lymphoblastic leukemia (ALL-L2) in children under the age of 17 years.  Near-haploidy is frequently associated with extremely poor prognosis.