Philadelphia chromosome in human multiple myeloma.

Four patients with multiple myeloma in whom a Ph1 chromosome was found were described; 1 patient had a (9;22) translocation, 2 had no evidence of a translocation, and 1 had a complex translocation (3;8;22). Ph1 chromosomes with standard (9;22) or with unusual translocations were recently found in various myeloproliferative disorders (other than chronic myelogenous leukemia) and in acute lymphoblastic leukemia. These findings point to the genesis of a Ph1 chromosome in diseases other than chronic myelogenous leukemia and other myeloproliferative disorders.