Cytogenetic alterations affecting BCL6 are predominantly found in follicular lymphomas grade 3B with a diffuse large B-cell component.
Recently, classical banding cytogenetic studies suggested that follicular lymphomas (FLs) grade 3 with preserved maturation to centrocytes (FL3A) are closely related to FL grades 1 and 2 and frequently harbor the t(14;18), whereas FL grade 3B, consisting of centroblasts exclusively, do frequently show 3q27 alterations. To clarify the prevalence of BCL6 and BCL2 rearrangements in FL and diffuse large B-cell lymphomas (DLBLs), we performed a large scale bicolor interphase cytogenetic (fluorescence in situ hybridization) study on 188 well-characterized B-NHLs classified according to the World Health Organization Classification of Tumors of the Lymphoid Tissues. BCL6 rearrangements were detected in a significantly higher number of FL3B with a DLBL component (12 of 22, 55%) compared with purely diffuse nodal DLBLs (19 of 77, 25%) and DLBLs with a well-documented primary extranodal origin (2 of 27, 7%) (P < 0.001). Five FL3B without a DLBL component were negative for both t(14;18) and 3q27 aberrations. FL grades 1/2 and FL3A were t(14;18)-positive in 88% and 64% of cases, respectively, but 3q27 alterations were identified in only four FL3A. These data exemplify different genetic pathways in the genesis of FLs with a high content of centroblasts and suggest that 3q27 rearrangements are predominantly associated with FL grade 3B harboring a DLBL component.
Katzenberger
Tiemo
T
Institute of Pathology, University of Würzburg, Josef-Schneider-Strasse 2, 97080 Würzburg, Germany. path054@mail.uni-wuerzburg.de.
Ott
German
G
Klein
Thomas
T
Kalla
Jörg
J
Müller-Hermelink
Hans Konrad
HK
Ott
M Michaela
MM
D002883:Chromosomes, Human, Pair 14 / Q000235:genetics; D002887:Chromosomes, Human, Pair 18 / Q000235:genetics; D002893:Chromosomes, Human, Pair 3 / Q000235:genetics; D020732:Cytogenetic Analysis; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D015321:Gene Rearrangement; D006801:Humans; D007124:Immunoenzyme Techniques; D017404:In Situ Hybridization, Fluorescence; D007399:Interphase; D016393:Lymphoma, B-Cell / Q000097:blood / Q000235:genetics* / Q000473:pathology; D008224:Lymphoma, Follicular / Q000097:blood / Q000235:genetics* / Q000473:pathology; D016403:Lymphoma, Large B-Cell, Diffuse / Q000097:blood / Q000235:genetics / Q000473:pathology; D009367:Neoplasm Staging; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics* / Q000378:metabolism; D051560:Proto-Oncogene Proteins c-bcl-6; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D014178:Translocation, Genetic / Q000235:genetics
D004268:DNA-Binding Proteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D051560:Proto-Oncogene Proteins c-bcl-6; D014157:Transcription Factors