ALL and CLL Flashcards
Does ALL commonly involve B or T cells?
Predominantly B cells
In what age group is ALL commonly seen?
Children under the age of ten
Is the ALL outcome more or less favourable in children compared to adults?
- More favourable in children
- children who are diagnosed early respond well
What cytogenetic risk group(s) give a good prognosis in Acute Lymphoblastic Leukaemia (ALL)?
- High hyperdiploidy (51-65 chromosomes)
- ETV6-RUNX1 (t(12;21))
What are the high risk cytogenetics (i.e. those with a poor prognosis) involved with ALL?
- intrachromosomal amplification of chr21 (iAMP21)
- Philadelphia chr: t(9;22)
- MLL rearrangements (e.g. t(4;11))
- Near haploidy (less than 30chr)
- low hypoploidy (30-39 chr)
- near triploidy (60-78 chr)
- complex karyotype
Provide details on use of ETV6-RUNX1 FISH probe to detect t(12;21) in ALL
- Probe covers ETV6 (chr12; green signal) and RUNX1 (chr21; red signal)
- Normal interphase signal pattern would be 2R2G
- Positive = 2 red/1 green/1 fusion = one normal copy of RUNX1 on 21q (one red), other red separated into two parts, one translocated onto der12 (one small red) and the other in the ETV6-RUNX1 fusion on der21. Also have one normal copy of ETV6 on 12p (one green)
Provide details on use of ETV6-RUNX1 FISH probe to detect high hyperdiploidy in ALL
- 51-65chr instead of 46
- Usually contains additional copies of chr21 therefore when this probe is used you get additional signals from extra chr21
- e.g. 4R2G signal pattern = two normal copies of ETV6 on chr12 and four normal copies of RUNX1 on chr21, confirming +21,+21 part of the karyotype
What cytogenetic abnormality is present in around 25% of ALL cases?
- t(12;21)
- marker of favourable outcome
- Detected by FISH as would be cryptic on g-banding
Provide details on use of ETV6-RUNX1 FISH probe to detect iAMP21 in ALL
- Consistently show five or more RUNX1 signals by FISH corresponding to 3 or more extra copies of RUNX1 on single abnormal chr21
- Signal pattern = cluster of red signals for iAMP21, one red for normal copy of chr21 and two green for two normal copies of chr12
What is the difference in FISH signal patterns observed when using ETV-RUNX1 probe in:
- t(12;21)
- High hyperdiploidy
- iAMP21
- 2 red, 1 green, 1 fusion
- 4 red, 2 green
- 2 green, 1 normal red, 1 amplified cluster of reds
Why is it crucial to distinguish between findings for ETV6-RUNX1 probe?
Because even though the FISH nomenclature can look similar the outcomes are so different:
- t(12;21)/high hyperdiploidy = good outcome
- iAMP21 = poor outcome
What age group is CLL more commonly seen in?
The older generation
In which population is CLL rare?
- Asian population
Of the various chromosomal anomalies seen in CLL, which is the most detrimental?
Deletion of 17p or mutation of the P53 gene
Other than del 17p or P53 mut, name three other prognostic markers in CLL
- Del 13q14 (favourable outcome)
- Trisomy 12 (intermediate outcome)
- Deletion of segment of ATM gene on chr11 (poor outcome)
