Genetic rearrangements in leukaemia and lymphoma / J.M. Goldman, D.G. Harnden.

Date:
1986
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Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: Genetic rearrangements in leukaemia and lymphoma / J.M. Goldman, D.G. Harnden. Source: Wellcome Collection.

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    40 GENETIC REARRANGEMENTS information on the production of heavy chain immunoglobulins and translocation on to chromosome 14 have also been described. The findings are discussed in greater detail in Chapters 5 and 8. However, recently published findings raise a number of questions regarding presently held views in BL. Thus, it has been reported^^ that non-endemic BL may be associated with a 6q- anomaly without evidence of involvement of chromosomes 8, 14, 2 or 22. The authors raise questions about the definition of BL, at least in cytogenetic terms, and of the involvement of various DNA sequences as a mechanism in the genesis of BL. In another report^^ cell lines derived from a homosexual patient with probable acquired immunodeficiency syndrome (AIDS) and BL with a consistent t(8;22) produced kappa light chains rather than the expected lambda chains. The findings indicated to the authors that the translocation in BL may occur as an event separate from immunoglobulin gene rearrangement or that the proposed hierarchical sequence of immunoglobulin gene rearrangement is not always adhered to. Furthermore, the authors^' indicated that in cells containing a translocation between the long arm of chromosome 8 and a chromosome bearing an immunoglobulin gene, activation and expression of the c-myc proto-oncogene may occur regardless of the immunoglobulin gene that is expressed. The frequent involvement of chromosome 1 in the karyotypic changes of BL - as it is in other lymphomas, leukaemias and cancers - was related to EBV status. All nine BL cell lines not associated with EBV were shown to contain an abnormahty of the long arm (bands Iq23-q24) of chromosome 1. The authors hypothesized^® that genetic information resembling that contained within the viral genome was present on the long arm of chromosome 1 and may bear upon the relationship between BL cell proliferation and EBV. Malignant lymphomas (other than Burkitt's) In lymphomas other than those of the Burkitt variety, certain karyotypic changes appear to be commonly associated with a particular type of disease (Table 2.10)'''^^'®''®^. Thus, t(8;14) of the same genesis as in BL appears often in the diffuse type of disease - including small noncleaved non-Burkitt lymphoma, as well as immunoblastic lymphoma. On the other hand, t(14;18)(q32.3;q21.3) appears to be commonly associated with follicular types Table 2.10 Types of lymphoma and chromosome changes t(8;14)(q24;q32) t(14;18)(q32;q21) t(ll;14)ql3;q32) del(6)(q21) Diffuse large cell Follicular Diffuse small cell Large cell, diffuse +7 Diffuse, large cell or follicular llq- + 12 Diffuse small cell Diffuse small cell