MOLECULAR ANALYSIS OF CUTANEOUS B-CELL AND T-CELL LYMPHOMAS

Among extranodal non-Hodgkin's lymphomas, primary cutaneous lymphomas (CLs) represent a consistent group of B- and T-cell malignancies. We i nvestigated the arrangement of Ig and T-cell receptor (TCR) genes, tog ether with the involvement of several oncogenes and the tumor-suppress or gene p53, in a panel of primary cutaneous B- and T-cell lymphomas ( CBCLs and CTCLs). Southern blot analysis was performed to detect rearr angements of the Ig, c-myc, bcl-1, bcl-2, bcl-3, bcl-6, and the NFKB2/ lyt-10 genes in 52 cases of CBCLs and of the TCR, bcl-3, and NFKB2/lyt -10 genes in 38 cases of CTCLs. tal-1 gene deletions were analyzed in CTCLs by means of polymerase chain reaction (PCR). p53 gene mutations were assayed using PCR, single-strand conformation polymorphism analys is, and direct DNA sequencing in CBCL and CTCL cases. Clonal rearrange ments of Ig genes or oncogenes were found in 25 of the 52 CBCLs. In pa rticular, we detected rearrangements of the bcl-1 locus (2 cases), the bcl-2 gene (2 cases), the NFKB2/lyt-10 gene (2 cases), and the bcl-6 gene (1 case); interestingly, 4 of these cases showed a germline arran gement of the Ig genes. Clonal rearrangements of TCR genes were detect ed in 37 of the 38 CTCLs. Rearrangements of the NFKB2/lyt-10 gene were present in 2 cases and tal-1 gene deletions in 3 CTCL cases; 953 gene mutations were detected in 1 CTCL case. Overall, our data indicate th at(1) clonal rearrangement of Ig genes is frequently undetectable by m eans of Southern blot in CBCLs ( 60%); (2) genetic lesions are involve d in a limited but significant fraction of primary CLs showing a molec ular marker of clonality (13/62; 20%); and (3) rearrangements of the b cl-1, bcl-2, or bcl-6 loci, associated with specific subsets of nodal lymphoid neoplasias, are rarely observed in CBCLs. Moreover, our resul ts suggest that tal-1 gene deletions may play a pathogenetic role in n on-acute T-cell malignancies and that, in the context of lymphoid mali gnancies, CLs may represent a favorable target for the possible oncoge nic potential of the NFKB2/lyt-10 gene. (C) 1995 by The American Socie ty of Hematology.