Page 444 - Clinical Hematology_ Theory _ Procedures ( PDFDrive )

428 PART 6 ■ Neoplastic Disorders

TABLE 22.7 Genetic Features of Selected B-Cell Neoplasms

Type of Neoplasm Chromosomal Abnormality Ig Genes

Chronic lymphocytic leukemia Trisomy 12; 13q R, U (50%), M (50%)

Hairy cell leukemia None known R, M

Burkitt lymphoma t(8;14)m t(2;8) R, M

t(8;22); c-myc; EBV /+

Lymphoplasmacytic lymphoma t(9;14) R, M

del 6 (q23)

Diffuse large B-cell lymphoma t(8;14), 3q R, M

BCL2, myc, BCL6

Ig, immunoglobulin genes; R, rearranged; M, mutated, U, unmutated; EBV Epstein-Barr virus.
,
Source: Handin RI, et al. (eds.). Blood: Principles and Practice of Hematology, 2nd ed, Philadelphia, PA: Lippincott Williams & Wilkins, 2003:75.

ly pho . A secon or , ixe cellul rity (MC), is ost light ch in v ri ble-region genes th t c n be tr nsl te into

co only i gnose in chil ren younger th n 10. T e thir protein bec use they preserve the correct re ing r e.

subtype, ly phocyte pre o in nce (LP) is lso ore co - Cells with out-o - r e V(D)J re rr nge ents ie by pop-

on in younger chil ren. tosis. In ture B cells, the expression o n ntigen recep-

tor is lso essenti l or cellul r surviv l bec use in uce
Non-Ho gkin ly pho (NHL) is ore co on

in boys th n girls. B se on the w y th t the tu ors eletion o the receptor in vivo le s to r pi poptosis.

beh ve, the subtypes o non-Ho gkin ly pho Most ture B-cell ly pho s, inclu ing Ho gkin ly -

i gnose in chil ren i er ro those th t evelop pho s, evelop s result o lign nt tr ns or tion o

in ults. T e two in subtypes o tu ors th t ger in l center or postger in l center B cells. Nor l B-cell

ect chil ren re the highly ggressive (high-gr e) evelop ent n B-cell tu ors epen on the expression o

tu ors: Burkitt ly pho , non-Burkitt ly pho , ntigen receptor or surviv l n growth o the B cells, with

n ly phobl stic ly pho . Although NHL types the exception o Ree -Sternberg cells in cl ssic Ho gkin is-

o tu ors re ore co on in ults, they re e se. T e ger in l center h s centr l role in both nor l

so eti es seen in chil ren. Pe i tric NHL exists s B-cell i erenti tion n the genesis o B-cell tu ors. T e

inter e i te-gr e tu ors: ollicul r l rge-cell ly - benef t o the ger in l center re ction is th t the e ense

pho , i use s ll cle ve cell ly pho , ntle g inst p thogens outweighs the incre se risk o lign nt

cell ly pho , peripher l cell ly pho , i u- tr ns or tion o the respon ing cells.

nobl stic i use l rge cell ly pho , n n pl stic Laboratory Analysis: Immunophenotyping,

Ki-1 l rge-cell ly pho (CD30+).
Genotyping, and Karyotyping

Pathophysiology Ly phoi neopl s s v ry in clinic l present tion n l bor -
tory ch r cteristics such s orphologic cellul r ppe r nce,

Although the etiology o ost ly pho s is unknown, the i unophenotypes, n genotypes. I unophenotype

potenti l role o virus in the p thogenesis o ly pho s is n lysis uses ntibo ies o v ri ble specif city to etect cel-

strongly suspecte . In hu ns, the evelop ent o B cells lul r ntigens in cell suspensions or in rozen or p r n-

in the bone rrow is initi te by the sse bly o genes or e be e tissue sections o ly ph no e or ss lesions

the v ri ble regions o the he vy n light ch ins o ntibo - ro surgic l biopsy. Flow cyto etry is the pri ry tool

ies in B-cell progenitors, e i te by process c lle V(D) use or phenotyping ost NHL n leuke i s th t rese -

J reco bin tion. In this process, the DNA loc te between ble one or ore st ges o nor l ly phocyte evelop ent

the re rr nging gene ele ents is elete ro the chro o- n ust be istinguishe ro re ctive proli er tions o

so e (or so eti es inverte ). Distinct gene re rr nge ents ly phocytes.

equip e ch B cell with in ivi u l olecul r clon l rkers.

Te expression ntibo y s n ntigen receptor on the Non-Hodgkin Lymphomas

sur ce o B cells is critic lly i port nt or the evelop ent

n surviv l o B cells. In evelop ent, the cells go through T e our ost co on subtypes o non-Ho gkin

n or ere progr o V(D)J re rr nge ents in which the Ly pho s (NHL) in chil ren inclu e three erive ro

only surviving cells re those th t h ve cquire he vy n ture cells: i use l rge B-cell ly pho (LBCL), Burkitt’s