Shared and Differential Gene Expression Profiles between Anaplastic Large Cell Lymphoma and Hodgkin Lymphoma Revealed by Supervised Clustering Analyses.

Although anaplastic large cell lymphoma (ALCL) and Hodgkin’s lymphoma (HL) are distinctive disease entities, there is a considerable overlap in morphological and immunophenotypical features between the two lymphoma subtypes. We performed a supervised clustering analysis comparing gene expression profiles of ALCL/HL cell lines with those of a variety of B-cell tumor cell lines. The result showed that the genes, expressions of which in the ALCL/HL cluster were lower than those in B-cell tumors, included a set of genes for protein tyrosine kinases. It is suggested that in ALCL/HL, genes encoding for signal transduction molecules downstream of T- and B- cell receptor are down-regulated, even though both diseases are of lymphoid cell origin. On the other hand, we found a total of 21 genes whose expressions were shared with ALCL and HL, including JUN, ems 1 oncogene (EMS1), cyclin-dependent kinase 6 (CDK6), and integrin alpha 4 (ITGA4). We next performed a second supervised clustering to effectively separate ALCL and HL. Of 87 genes differentially expressed between ALCL and HL, 54 genes were expressed to a higher degree in ALCL than HL, whereas expression levels of 33 genes were higher in HL than ALCL. The ALCL-associated genes included cdk inhibitors, p19^INK4d and p21^WAF1/CIP1, suggesting that genes involved in cell cycle-regulating pathways are differentially expressed between ALCL and HL. Our study provided potentially interesting molecules that can account for the similarity and difference of ALCL and HL.