A subtractive cloning procedure was used to characterize the molecular changes involved in transformation of normal myoblasts to rhabdomyosarcoma (RMS) cells. Here we describe the cloning of DRAL, a novel LIM-domain protein expressed in primary myoblasts but down-regulated in the RMS cell line RD. DRAL is a LIM-only protein with five LIM domains whereby one LIM domain consists only of the second half of the consensus motif. Interestingly, down-regulation of DRAL was not confined to the RD RMS cells, but was a phenomenon extended to other RMS cell lines of both embryonal and alveolar subtype, and to some breast cancer cell lines. Analysis of the expression pattern in normal human tissues revealed that DRAL is expressed at high levels in the heart, suggesting an important function in the specification of the terminally differentiated phenotype of heart muscle cells. Immunofluorescence studies using an antibody directed against recombinant DRAL localized the protein predominantly in the nucleus of cultured cells. On the basis of these results, we conclude that down-regulation of DRAL correlates with the tumor phenotype of RMS cells.

o 1996 Wiley-Liss, Inc.

o 1996 Wiley-Liss, Inc.

Chronic myeloid leukemia without the Philadelphia chromosome (Ph1-CML) is described and distinguished from chronic myeloid leukemia with the Philadelphia chromosome (Ph1+CML) on the basis of clinical and autopsy findings of four cases. Ph1-CML showed clinical, hematological, and patho-anatomical features which could be regarded as typical. Patho-anatomically Ph1-CML differed from Ph1+CML in the variable maturation of the leukemic proliferation in the bone marrow and extramedullary infiltrates. Up to the terminal phase Ph1-CML can be of an extremely mature cell type. However, it can also show myeloblastic transformation after an initially mature cell stage. Ph1-CML infiltrates are found in tissues and organs which Ph1+CML usually does not infiltrate or only to a low degree until a blastic crisis. On the basis of its course and clinical and patho-anatomical features Ph1-CML looks like an atypical chronic myeloid leukemia. However, it is better called an acute myeloid leukemia of the mature cell type.

Observations in six adult patients with leukaemic differential white counts, predominantly mature-celled, and with hepatosplenomegaly show that the mature-celled but fulminant (para-)neutrophil leukaemia must be differentiated from Ph1-positive chronic myeloid leukaemia. This (para-)neutrophil leukaemia is probably identical with the previously described atypical chronic myelosis of the adult, chronic myeloid leukaemia of childhood and the Pelger-like chronic myeloid leukaemia. Cardinal signs are a mature-celled differential count, short life expectancy (1 year), initial platelet deficiency, increased activity of granulocyte alkaline phosphatase, absence of Ph1-chromosome, and poor therapeutic response to busulfan. This curious and yet apparently not uncommon disease has been observed in the adult age group predominantly in men. The frequently high HbF level observed in juvenile chronic myeloid leukaemia could not be demonstrated in adults. Some of these neutrophil leukaemias are characterized by medullary fibrosis and terminal increase of immature blast cells (blast crises?) of which the diagnostic reliability is still disputed.