To investigate the influence of ETV6/CBFA2 on cellular transformation, the fusion gene was cloned into a murine ecotropic retroviral vector and transduced into IL-3-dependent Ba/F3 and 32Dcl.3 and IL-7-dependent IxN/2b murine hematopoietic cell lines.     ///    We further investigated the effect of ETV6/CBFA2 expression in vivo by generating transgenic mice in which expression of the fusion was directed to lymphoid cells using the immunoglobulin heavy chain enhancer/promoter.     ///    We conclude that the expression of ETV6/CBFA2 alone is not sufficient for induction of growth factor independence in hematopoietic cell lines or hematologic disease in transgenic mice..     ///    " ETV6/CBFA2 (TEL/AML1) is the most frequent genetic abnormality associated with acute lymphoblastic leukemias in children, and is associated with a favorable prognosis. "    ///    "The mice did not develop a malignant hematologic disorder, nor did they display histopathologic, morphologic, or immunophenotypic abnormalities, although ETV6/CBFA2 expression was confirmed in each line. "    ///    The expression of ETV6/CBFA2 (TEL/AML1) is not sufficient for the transformation of hematopoietic cell lines in vitro or the induction of hematologic disease in vivo..     ///    "However, although Western blot analysis demonstrated expression of each variant, none of the stable cell lines expressing CBFA2/ETV6 or the variants conferred factor-independent growth. "    ///    "Different variants of ETV6/CBFA2, corresponding to CBFA2 alternatively spliced variants, and the reciprocal product CBFA2/ETV6, were stably expressed in each of these cell lines. "