Flashcards in 18.06.17 - Mature B cell neoplasms, CLL, MM Deck (44):
Immunoglobulins are composed of heavy chains (IGH) and light chains; either kappa (IGK) or lamba (IGL). What are the genomic loci of IGH, IGK and IGL?
IGH - 14q32
IGK - 2p12
IGL - 22q11
Give an overview of CLL, including incidence.
1) Chronic mature B-cell neoplasm
2) Caused by proliferation and accumulation of monomorphic B lymphocytes in PB, BM, LN, spleen.
3) Accumulation of mature, dysfunction B cells prevents the haematopoiesis of other normal blood cells leading to cytopaenias.
4) CLL only differentiated from SLL by leukaemic appearance.
5) Most common leukaemia in Western adults 12.8/100,000 by age 65, accounts forr 6.5 of NHL. Hig(2.1:1.5)
6) Highest genetic predisposition of haematological malignancies 5-10% CLL have a family history
What are the presenting features of CLL?
May be asymptomatic with incidental detection, bit can present with:
2) Autoimmune haemolytic anameia
5) Lymphadenopathy or extra-nodal infiltrates
CLL may proceed through distinct clinical phases, describe these.
Pre-malignant - monoclonal B-cell lymphocytosis (MBL)
Transformation to Richter's syndrome - aggressive lymphoma - median survival <1 year.
What percentage of CLL patients develop a lymphoma pre- or post-treatment?
e.g. diffuse large B-cell lymphoma (DLBCL) and classical Hodgkin lymphoma.
What is the potential difficulty of karyotyping for CLL?
Cells may not divide in culture way
Addition of TPA (mitogen) is helpful
What percentage of CLL patients will have a clonal abnormality detected by karyotyping or FISH?
50% by karyotyping
>80% by FISH
What are the most common chromosome abnormalities detected in CLL patients. What is their associated prognosis?
Isolated del 13q14.3 (mono-or biallelic) - 55% - favourable
del(11q23) (ATM) - 18% - poor
trisomy 12 - 16% - intermediate
del(17p13) (TP53) - 7% - poor
Which FISH probes are used for new CLL referrals and to track progression of disease?
ATM/TP53 for detection of gain/loss of signal
12/13 - for detection of gain or loss of signal
Which CLL rearrangements are considered to be 'first-stage' abnomalities, and which rearrangements may indicate progressive disease?
First-step: T12 and del13q14.3 similarly represented through all stages of disease. Clonal driver mutations.
Progression: del 11q23 (ATM deletion)
What is the prognostic significance of a TP53 (17p13) deletion?
Frequently acquired following treatment. Poor prognosis as patients do not respond to standard CLL therapies Associated with a higher genetic complexity. Mutations of TP53 are commonly seen where deletions have been detected on the other allele.
The detection of chromosome abnormalities can help to distinguish CLL from other lymphoproliferative disease. GIve an example of a differential diagnosis for CLL.
Mantle cell lymphoma. IGH-CCND1
- is also seen in atypical CLL
~20% of CLL patients have a rearrangement involving IGH. What is the chromosomal position of IGH, what is the prognosis for CLL patients with IGH rearrangements?
Poor prognosis as often indicative of a complex karyotype
Which IGH rearrangement is commonly seen with trisomy 12 in CLL patients? What is its prognosis?
Give three examples of IGH rearrangements that may be seen in CLL patients, and associated prognosis if known.
1) IGH-BCL11A t(2;14)(p16.1;q32)
2) IGH-BCL2 t(14;18)(q32;q21) - no association with complex karyotype or aggressive features
3) IGH-MYC t(8;14)(q24;q32) -subgroup of CLL with poor prognosis. May be secondary abnormality with role in transformation.
A number of recurrent somatic mutations have been identified in CLL by NGS. Give some examples and their prognostic significance if known.
4-15% have a mutation of NOTCH1. Truncation of NOTCH1 removes the PEST sequence, which leads to the accumulation of an active protein form. Poor prognosis.
SF3B1 (ubiquitously expressed splicing factor) is found to be mutated in 5-17%, associated with a poor prognosis and drug resistance.
With with chromosome aberration are NOTCH1 mutations commonly seen with?
More commonly seen with unmutated IGVH CLL
Four prognostic subgroups have been developed for CLL that are an integration of cyto and molecular finding. What findings are associated with each category?
High risk - TP53del +/or BIRC3 abn. 10 year survival = 29%
Intermediate risk = NOTCH1 +/or SF3B1 +/or ATM del (11q22-23). 10 year survival 37%
Low risk = +12 or normal cyto. 10 year survival = 57%
Very low risk = isolated 13q14.3del. 10 year survival 69.3%.
What diagnostic strategies differentiate CLL from other lymphoproliferative diseases? e.g. hairy-cell leukaemia or leukaemia manifestations of MCL
Immunophenotype of circulating lymphoid cells
- CD5+, CD10-, CD19+, CD23+, CD43+, CD103-, BCL6-
Marrow examination not required for diagnosis, but required to determine complete response.
Why is FISH used for CLL patients?
To determine cytogenetic aberrations that may not be detectable by karyotyping and may inform therapy.
What clinical guidelines are in place for CLL testing.
No ACGS CLL specific guideline
ACGS Haemato-oncology BPG
Other than karyotyping and FISH, what other genetic testing methods may be useful in CLL patients?
NGS - detection of somatic mutation
SNP arrays - LoH detection
Other microarray for CN detection
What are the advantages and disadvantage of using array-based techniques in CLL patients?
Does not require cell culture, therefore issue of low proliferation overcome.
May not detect mosaicism sensitively enough and low level clones are missed.
What is the treatment for CLL?
Patients treated with the onset of symptoms, or disease progression.
Patients usually follow a pattern of remitting and relapsing. Treatment is delivered within context of clinical trial
- FLAIR (fit patients)
- RIAltO (unfit patients)
What are the five of the key recommendations for CLL patients stated by the British Committee for Standards in Haematology?
1. All patients are screened for TP53 abnormality pre-treatment.
2. Cyclophoshamide is recommended for fit, previously untreated or relapsed patients who require treatment and who have not entered a clinical trial
3. Alemtuzumab should be considered for previously untreated or relapsed patients with a TP53 abnormality and those with fludaribine-refractory disease who require treatment
4. Suitable patients with poor risk factors such as a TP53 abnormality and those who relapse early after intensive therapy should be considered for allogentic transplantation
Patients should be offered entry into clinical trials where possible
What are the clinical variants of plasma cell myeloma/multiple myeloma?
1. Nonsecretory myeloma
2. Smoldering myeloma
3. Indolent myeloma
4. Plasma cell leukaemia
Give a brief overview of multiple myeloma.
Accounts for ~1% of tumours and 10-15% of malignant neoplasms.
Annual incidence ~60-70/million
More common in men (1.4:1)
More common in AA population
Median age ~70 (rare in <40)
Genetic predisposition. 3.7 fold increase is first degree relative affected.
What is MGUS?
Monoclonal gammopathy of undertermined significance
Precursor state to myeloma
Non-malignant and usually asymptomatic
Plasma cell content <10%
Patients have 1% risk by year of progression to myeloma and require observation.
What is smoldering myeloma?
Intermediate between MGUS and MM
Stable PC content 10-30%
No osteocytic lesions
No other clinical findings characteristic of MM
What is myeloma?
Plasma cell neoplasm. Accumulation of clonal plasma cells in BM.
PC content >10%
Expansion of a clone of IG-secreting, heavy-chain class-switched, terminally differentiated B-cells that typically secrete a monoclonal immunoglobulin called paraprotein or M-protein detectable in serum and/or urine.
What is the typical presentation of myeloma?
Four leading symptoms:
R - renal failure, due to proteinuria
A - anaemia, due to BM replacement.
B - bone disease - lytic bone lesions, hypercalcaemia, fractures, osteroporosis, bone pain
What is extramedullary MM?
More aggressive form and may be called secondary or primary plasma cell leukaemia.
What proportion of new MM patients will have an abnormality detected by conventional karyotyping? by FISH?
What are the two subgroups of MM patients following cyotgenetic analysis? and what are the associated prognoses?
1) Hyperdiploid (~50%) 48-75 chr (usually trisomy of 8 chromosomes, odd numbers - 3, 5, 7, 9, 11, 15, 19, 21) favourable prognosis
2) Non-hyperdiploid (~50%) <48, >75, usually include translocations (IGH, 70%) and hemizygous 13del, poor prognosis
What are the five major IGH rearrangement partners seen in MM?
t(4;14)(p16.3;q32) - FGFR3
t(11;14)(q13;q32) - CCND1
t(14;16)(q32;q23) - MAF
t(6;14)(p21;q32) - CCND3
t(14;20)(q32;q11) - MAFB
What is the genomic location of FGFR3? What frequency its rearrangement with IGH seen in MM patients, and what is its prognostic significance?
What is the genomic location of CCND1? What frequency its rearrangement with IGH seen in MM patients, and what is its prognostic significance?
What is the genomic location of MAF? What frequency its rearrangement with IGH seen in MM patients, and what is its prognostic significance?
What is the genomic location of CCND3? What frequency its rearrangement with IGH seen in MM patients, and what is its prognostic significance?
What is the genomic location of MAFB? What frequency its rearrangement with IGH seen in MM patients, and what is its prognostic significance?
Poor (some evidence to suggest very aggressive and therefore very poor prognostic indicator).
Which genetic changes indicate disease progression in MM patients?
1) Monosomy/del 13q (50%) - close association with t(4;14)
2) Del 17p/TP53 (10%) - rare, late event, v. poor prognosis
3) Loss 1p/gain 1q - (40% of new, 70% at relapse) - poor prognosis
4) MYC translocation/amplifications (45% in advanced MM) - late event in tumour progression
Summarise the diagnostic strategy for MM patients.
Low proliferation makes karyotyping difficult (3-4 unstimulated culture recommended)
Instead, FISH on plasma cell interphase nuclei for specfic poor prognostic rearragements. Cell selection prior to FISH to ensure myeloma cells are tested. PCE recommended
ImmunoFISH - tagged cells
Which FISH probes are used for MM patients?
t(4;14) - IGH/FGFR3
t(14;16) - IGH/MAF
t(11;14) - IGH/CCND1
t(14;20) - IGH/MAFB