FLRG (FOLLISTATIN-RELATED GENE), A NEW TARGET OF CHROMOSOMAL REARRANGEMENT IN MALIGNANT BLOOD DISORDERS

We report here the molecular study of t(11;19)(q13;p13) translocation observed in a case of B-cell chronic lymphocytic leukemia. This transl ocation leads to the juxtaposition of the CCND1 gene on chromosome 11 to a new transcriptionnal unit on chromosome 19. The cDNA of this new evolutionarily conserved gene (named FLRG for Follistatin-Related Gene ) codes for a secreted glycoprotein of the follistatin-module-protein family. FLRG is expressed in a wide range of human and murine adult ti ssues and its expression seems to be tightly regulated during murine e mbryogenesis. Its transcripts could not be detected in hematopoietic c ells from all lineages and in particular in cells from lymphoid B and T lineage except in the t(11;19)-carrying leukemia described here. A g reat variability of expression is observed among the other tumoral cel l lines analysed. Besides the t(11;19)-carrying leukemia described in this work, structural rearrangements of the FLRG locus have been found in a non-Hodgkin lymphoma, suggesting that it may play a role in leuk emogenesis.