RELATIONSHIP BETWEEN BCL-2 AND MYC GENE-EXPRESSION IN HUMAN NEUROBLASTOMA

We have investigated the relationship between the expression of bcl-2 and myc family genes in primary human neuroblastoma (NB) tumors and ce ll lines, Of 20 NB tumors examined, bcl-2 transcripts were expressed a t variable levels in 16 tumors of all clinical stages. Of the 2 tumors with N-myc amplification, one expressed bcl-2 at a high level, wherea s the other did so at a low level, In contrast, all NB tumors showed t he expression of c-myc and/or N-myc transcripts. Similarly, of 9 NB ce ll lines with N-myc amplification examined, 6 expressed bcl-2 at high levels, whereas the other 3 expressed it at barely detectable levels, The 3 cell lines without N-myc amplification also expressed bcl-2 prot ein at high levels, All NB cell lines tested expressed either c-myc or N-myc protein, These data suggest that in NB, there is no significant association between bcl-2 expression and advanced tumor stages or N-m yc amplification. The data also show that bcl-2 expression does not al ways coincide with myc expression in NE, suggesting that bcl-2-indepen dent mechanisms may exist in the bcl-2-negative NE tumor cells in orde r to suppress the cell death promoting action of high myc expression.