R. Suzuki et al., Prognostic significance of CD56 expression for ALK-positive and ALK-negative anaplastic large-cell lymphoma of T/null cell phenotype, BLOOD, 96(9), 2000, pp. 2993-3000
Anaplastic large cell lymphoma (ALCL) is a distinct entity of non-Hodgkin l
ymphoma, characterized by a proliferation of pleomorphic large lymphoid cel
ls that express CD30, Recent studies have found that a subset of ALCL aberr
antly expresses a chimeric anaplastic lymphoma kinase (ALK) protein as a re
sult of t(2; 5)(p23;q35) or variant translocations. ALK-positive ALCLs feat
ure good prognosis, but some of them lead to poor outcomes. Since CD56 is e
xpressed in some ALCLs, its clinical significance was examined in a series
of T/null cell type ALCLs. Of 143 patients, 83 (58%) showed ALK-positive st
aining, and of 140 patients, 25 (18%) expressed CD56. The ALK-positive subg
roup was characterized by a younger age of onset (P < .0001), lower serum l
actate dehydrogenase level (P = .01), better performance status (P = .03),
less frequent extranodal involvement (P = .01), lower international prognos
tic index (IPI) categories (P = .002), and superior survival (P = .0009) in
comparison with the ALK-negative group, suggesting that ALK is a specific
marker defining a distinct subtype. CD56(+) cases showed a significantly po
or prognosis overall (P = .002) as well as in both ALK-positive and ALK-neg
ative subgroups (P = .02 and P = .04, respectively). Multivariate analysis
con-firmed that CD56 is independent of other prognostic factors, including
IPI. Although CD56(+) cases showed a higher incidence of bone involvement,
no other differences in clinicopathologic parameters were found between the
CD56(+) and CD56(-) groups. These findings suggest that CD56 is not a mark
er to identify a distinct subtype of ALCL, but a strong clinical prognostic
factor. Effective therapeutic approaches should be explored for high-risk
ALCL patients, who can be identified by means of a prognostic model, includ
ing CD56. (C) 2000 by The American Society of Hematology.