Chromosomes of Two Cases of Human Chronic Myeloid Leukæmia

Abstract

THREE reports have described an abnormally small chromosome (Ph¹) replacing one of the four smallest, acrocentric autosomes in the chromosome complement of cells from patients with chronic myeloid leukæmia^1–3. The Ph¹ chromosome has been found in cultured peripheral blood or bone marrow cells from twenty patients with chronic myeloid leukæmia, ranging from untreated cases to those in terminal, acute stages, and a causal relationship between the chromosome abnormality and the disease has been suggested. Tough et al.³ failed to find the Ph¹ chromosome in five cases of this leukæmia. Two of these had entered an acute leukæmia phase where diverse chromosome changes can be expected, whereas the other three cases had in common an unusually long history after diagnosis and followed a relatively benign course. Two of these latter cases had a previous history of radiotherapy for ankylosing spondylitis and there was a high probability that these leukæmias were radiation induced.