Chromosomes and causation of human cancer and leukemia. VII. The significance of the Ph1 in conditions other than CML

Two cases of Ph1‐positive AML, and one case of Di Guglielmo's syndrome are reported. A review of the literature reveals that the occurrence of a Ph1‐chromosome has been observed in a number of cases with these diseases, indicating that the Ph1‐chromosome is not solely specific for CML. By correlating cytogenetic and histologic bone marrow data, some evidence is presented that the process leading to the genesis of a Ph1‐chromosome may affect the bone marrow cells either at or beyond the stem cell level.