Waldenström's macroglobulinemia pathophysiology: Difference between revisions

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::*Gains of 3q13-q28, 6p and 18q
::*Gains of 3q13-q28, 6p and 18q
===Associated Conditions===
===Associated Conditions===
Several studies showed an increased incidence of second cancers in patients with Waldenström macroglobulinemia.<ref name="Acs">{{cite journal |vauthors=Morra E, Varettoni M, Tedeschi A, Arcaini L, Ricci F, Pascutto C, Rattotti S, Vismara E, Paris L, Cazzola M |title=Associated cancers in Waldenström macroglobulinemia: clues for common genetic predisposition |journal=Clin Lymphoma Myeloma Leuk |volume=13 |issue=6 |pages=700–3 |year=2013 |pmid=24070824 |doi=10.1016/j.clml.2013.05.008 |url=}}</ref>
:*Diffuse large B-cell lymphoma
:*Myelodysplastic syndrome/Acute myeloid leukemia
:*Brain tumor
:*Renal MALT lymphoma <ref name="AC">{{cite journal |vauthors=Chi PJ, Pei SN, Huang TL, Huang SC, Ng HY, Lee CT |title=Renal MALT lymphoma associated with Waldenström macroglobulinemia |journal=J. Formos. Med. Assoc. |volume=113 |issue=4 |pages=255–7 |year=2014 |pmid=24685302 |doi=10.1016/j.jfma.2011.02.007 |url=}}</ref>
:*Renal MALT lymphoma <ref name="AC">{{cite journal |vauthors=Chi PJ, Pei SN, Huang TL, Huang SC, Ng HY, Lee CT |title=Renal MALT lymphoma associated with Waldenström macroglobulinemia |journal=J. Formos. Med. Assoc. |volume=113 |issue=4 |pages=255–7 |year=2014 |pmid=24685302 |doi=10.1016/j.jfma.2011.02.007 |url=}}</ref>



Revision as of 19:25, 10 November 2015

Pathogenesis

Waldenström Macroglobulinemia is uncontrolled clonal proliferation of terminally differentiated B lymphocytes, which are normally involved in humoral immunity.[1] In Waldenström Macroglobulinemia, peripheral B lymphocyte are stimulated to undergo somatic hypermutation of the immunoglobulin heavy chain gene in the germinal center, without class switching.

Genetics

  • Development of Waldenström Macroglobulinemia is the result of multiple gene mutations.[2]
  • Genes involved in pathogenesis of Waldenström Macroglobulinemia are:
  • MYD88 L265P in chromosome 3p22.2
  • CXCR4
  • MYD88: has a role in toll-like receptor and interleukin-1 receptor signaling causing activation of transcription factors of the NF-kB family. Thus, activating point mutation of MYD88 augments growth and survival of both normal and neoplastic B cells by preventing apoptosis. MYD88 also has role in BTK signaling which also helps in B cell growth and survival. Point mutation of MYD88 leads to leucine (L) to proline (P) substitution in codon 265 (L265P) of MYD88 and produces constantly overactive protein causing proliferation of malignant cells that should normally undergo apoptosis.[2][3]
  • Patients with Waldenström Macroglobulinemia with co-existing mutation of MYD88 & CXCR4 are more likely to have hyperviscosity syndrome and bone marrow involvement.
  • Waldenström Macroglobulinemia is associated with following chromosome abnormalities:[2]
  • Deletions of 6q23 and 13q14, and
  • Gains of 3q13-q28, 6p and 18q

Associated Conditions

Several studies showed an increased incidence of second cancers in patients with Waldenström macroglobulinemia.[4]

  • Diffuse large B-cell lymphoma
  • Myelodysplastic syndrome/Acute myeloid leukemia
  • Brain tumor
  • Renal MALT lymphoma [5]

Pathology

Gross pathology

Microscopic pathology

Immunohistochemistry

Malignant cells in Waldenström Macroglobulinemia:[2]

  • Express Pan B-cell antigens (CD19, CD20, CD22, CD79A)
  • Some express CD5
  • Variable expression of CD11c, CD43, CD25.
  • Most express IgM surface immunoglobulin, while fewer express IgG or IgA and lack IgD.

References:

  1. Waldenström's macroglobulinemia. Wikipedia (2015)https://en.wikipedia.org/wiki/Waldenström%27s_macroglobulinemia#Pathophysiology Accessed on November 6, 2015
  2. 2.0 2.1 2.2 2.3 Epidemiology, pathogenesis, clinical manifestations and diagnosis of Waldenström macroglobulinemia. UpToDate (2015)http://www.uptodate.com/contents/epidemiology-pathogenesis-clinical-manifestations-and-diagnosis-of-waldenstrom-macroglobulinemia?source=see_link Accessed on November 9, 2015
  3. Waldenström macroglobulinemia. Genetics Home Reference (2015)http://ghr.nlm.nih.gov/condition/waldenstrom-macroglobulinemia Accessed on November 9, 2015
  4. Morra E, Varettoni M, Tedeschi A, Arcaini L, Ricci F, Pascutto C, Rattotti S, Vismara E, Paris L, Cazzola M (2013). "Associated cancers in Waldenström macroglobulinemia: clues for common genetic predisposition". Clin Lymphoma Myeloma Leuk. 13 (6): 700–3. doi:10.1016/j.clml.2013.05.008. PMID 24070824.
  5. Chi PJ, Pei SN, Huang TL, Huang SC, Ng HY, Lee CT (2014). "Renal MALT lymphoma associated with Waldenström macroglobulinemia". J. Formos. Med. Assoc. 113 (4): 255–7. doi:10.1016/j.jfma.2011.02.007. PMID 24685302.