title: Follicular origin of a subset of CD5+ diffuse large B-cell lymphomas.
abstract: Most follicular lymphomas (FLs) have a phenotype consistent with the origin from CD5-, CD10+, bcl-6+ follicular center cells and can progress to diffuse large B-cell lymphoma (DLBCL). CD5 is expressed in about 10% of DLBCLs, showing prognostic value, whereas expression is rare in FL. We present 6 cases with coexisting features of CD5+ FL and CD5+ DLBCL, supporting a follicular origin for some CD5+ DLBCLs. The follicular areas showed a meshwork of CD21+ follicular dendritic cells that were lacking in the DLBCL areas. All cases showed a clonal CD19+, CD20+, CD5+, and CD10+ population in both follicular and diffuse areas. Molecularly, 4 of 6 cases demonstrated immunoglobulin heavy chain rearrangements and 1 case, a bcl-2/immunoglobulin heavy chain gene rearrangement. Somatic hypermutations were high in all 4 cases, in keeping with their germinal center origin. Four of five patients died of disease within 42 months, consistent with the proposed prognostic value of CD5 expression in DLBCL. Our data describe an aggressive variant of CD5+ FL suggesting the follicular origin of some CD5+ DLBCLs.
authors.affiliation: Center for Experimental Research and Medical Studies and Department of Biomedical Sciences and Human Oncology, University of Turin, Turin, Italy.
authors.forename: Andrea D
authors.initials: AD
authors.lastname: Manazza
authors.forename: Lisa
authors.initials: L
authors.lastname: Bonello
authors.forename: Marco
authors.initials: M
authors.lastname: Pagano
authors.forename: Luigi
authors.initials: L
authors.lastname: Chiusa
authors.forename: Domenico
authors.initials: D
authors.lastname: Novero
authors.forename: Alessandra
authors.initials: A
authors.lastname: Stacchini
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Martini
authors.forename: Umberto
authors.initials: U
authors.lastname: Vitolo
authors.forename: Corrado
authors.initials: C
authors.lastname: Tarella
authors.forename: Giorgio
authors.initials: G
authors.lastname: Inghirami
authors.forename: Giorgio
authors.initials: G
authors.lastname: Palestro
authors.forename: Roberto
authors.initials: R
authors.lastname: Chiarle
mesh_terms: D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism*; D018956:CD5 Antigens / Q000378:metabolism*; D004252:DNA Mutational Analysis; D005260:Female; D015326:Gene Rearrangement, B-Lymphocyte, Heavy Chain; D006801:Humans; D007150:Immunohistochemistry; D016130:Immunophenotyping; D016393:Lymphoma, B-Cell / Q000473:pathology*; D008224:Lymphoma, Follicular / Q000473:pathology*; D016403:Lymphoma, Large B-Cell, Diffuse / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D011379:Prognosis
chemical_list: D014408:Biomarkers, Tumor; D018956:CD5 Antigens