Southern blotting was used to detect rearrangement of the bcl-2 gene in 104 cases of non-Hodgkin's lymphoma subclassified by the Working Formulation, 24 cases of B cell chronic lymphocytic leukemia (B-CLL) and 14 cases of T cell malignancy. Earlier workers reported rearrangement of this gene (located on chromosome 18) in a major fraction of follicular lymphomas, lymphomas in which a 14;18 chromosome translocation is frequently observed. In the present study, bcl-2 was rearranged in 30% (11 of 37) of follicular lymphomas and 19% (11 of 58) of diffuse lymphomas of follicle center cell lineage. In 18 of 19 samples studied, the rearranged bcl-2 fragment also hybridized with a probe for the joining region of the immunoglobulin heavy chain gene located on chromosome 14, indicating a 14;18 translocation. In lymphomas not derived from follicle center cells, ie, diffuse lymphomas of small B lymphocytes, B-CLL and T cell neoplasms, the bcl-2 gene was always in germline configuration. The frequent rearrangement of bcl-2 in a variety of B cell lymphomas of diffuse morphology (small cleaved cell, large cell, small noncleaved cell and immunoblastic) is noteworthy.
The cell lineage of suspensions prepared from 85 non-Hodgkin's lymphomas was investigated with a panel of 10 monoclonal antibodies and conventional surface marker techniques. Surface immunoglobulin, assessed with specific heteroantisera, proved to be the most useful characteristic and defined the clonal character and B-cell lineage of 63 specimens: almost all nodular lymphocytic (21 of 22) and diffuse lymphocytic (11 of 13) lymphomas, most diffuse histiocytic (29 of 33) and diffuse mixed (2 of 2) lymphomas, and a few nodular mixed (2 of 12) and nodular histiocytic (0 of 3) lymphomas. Monoclonal antibodies provided useful ancillary surface marker criteria. Thus, positivity with OKT1 (which detects both thymic and peripheral T cells) in the absence of reactivity with monoclonal antisera, which detect only peripheral T cells (OKT3, OKT4, OKT8, and OKT11), was seen only in diffuse lymphocytic lymphoma of B lineage. Ia-like antigen could be demonstrated in all B-cell lymphocytic lymphomas and most B-cell diffuse histiocytic lymphomas. Approximately one-half of diffuse histiocytic lymphomas also reacted with OKT9, which detects the transferrin receptor, while few lymph nodes involved by other conditions displayed this reactivity. Most diffuse histiocytic lymphomas and many non-Hodgkin's lymphomas of other subtypes reacted with OKT10, an antiserum that detects an antigen on replicating lymphoid cells. The lineage of approximately one-fourth of the lymphoma suspensions was not resolved conclusively: In most of these, T lymphocytes predominated with a normal proportion of inducer-helper (OKT4) and cytotoxic-suppressor (OKT8) cells. The inability to establish the clonal character of T-cell proliferation in cell suspensions remains an obstacle to completely defining the lineage of non-Hodgkin's lymphomas.
We used Southern blot analysis to investigate the T cell receptor and immunoglobulin (Ig) genes in tumor DNA derived from 13 patients with acute lymphoblastic leukemia (ALL). Rearrangement of both alleles of the T cell receptor beta chain gene was demonstrated in the three individuals with T cell ALL, while the Ig genes remained in germline configuration. In contrast, in nine of ten patients with non-T, non-B ALL (seven common ALL antigen [CALLA]-positive), Ig genes were rearranged while the T cell receptor genes were intact: the noteworthy exception was a CALLA-positive individual in whom one allele of the T cell receptor was rearranged and in whom a minor rearranged Ig band was detected as well. This exception indicates that CALLA-positive non-T, non-B ALL includes proliferations that have undergone an initial genetic step toward T cell differentiation. With probes now available for both the Ig and T cell receptor genes, analysis of genomic tumor DNA is useful in all variants of ALL.
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