The (2;5)(p23;q35) translocation which results in the fusion of the NPM (nucleophosmin) gene on chromosome 5q35 with the novel ALK (anaplastic lymphoma kinase) gene on chromosome 2p23 [S.W. Morris et al., Science (Washington DC), 263: 1281–1284, 1994] is associated with Ki-1 (CD30)-positive anaplastic large cell lymphomas (ALCL); a group of morphologically and immunophenotypically heterogeneous high grade large cell lymphomas (LCL), which share many characteristics with Hodgkin's disease (HD), including the presence of variable numbers of Reed-Sternberg-like cells and the expression of CD30 antigen.

Using a DNA probe immediately 5′ to the NPM coding sequences, we have examined NPM gene rearrangements by Southern blotting in 5 Ki-1-positive lymphoma cell lines carrying a translocation involving the 5q35 breakpoint and in 25 Ki-positive lymphoma tumors, including 9 HD. Using this method, we detected rearrangements in all cell lines with apparent clustering of the breakpoints. Analysis of 25 Ki-1-positive lymphomas indicated that only 4 neoplasms, including two HD, had NPM gene rearrangements. Thus, our findings suggest that only a subset of ALCL has detectable involvement of the NPM gene. In addition, the presence of NPM gene rearrangements in HD indicates the involvement of this gene in a fraction of HD. Thus, NPM gene rearrangements may identify a certain subtype in ALCL and HD which may be closely related.


This work was supported by National Cancer Institute Grants CA 39860 (to C. M. C.), K08 CA 01702 (to S. W. M.), the Research Fellowship Award 5 F31 CA60352-02 (to F. B.), and the American Lebanese Syrian Associated Charities of St. Jude Children's Research Hospital.

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