Loss of the Y chromosome from normal and neoplastic bone marrows

Loss of the Y chromosome is a feature of haematologically normal bone marrow in elderly males, but it is also found in haematological malignancy. We describe — Y as the sole karyotypic abnormality in 147 cases (66 from 802 unselected cases and a further 81 cases selected for — Y) with the following diagnoses: no haematological malignancy (N), myelodysplastic syndrome (MDS), acute myeloid leukaemia (AML), and myeloproliferative disorder (MPD). The frequency of — Y in the 802 unselected N, MDS, and AML cases was 7.7%, 10.7%, and 3.7%, respectively. It could not be evaluated in MPD because there were too few cases. In N and MDS cases the frequency increased in a similar fashion over the age of 60 years. The 147 — Y cases showed a similar increase in distribution with advancing age in all four clinical categories. The degree of loss of Y (% — Y) cells per patient) increased with age in N and MPD patients but not in those with MDS or AML. This study suggests that in elderly men — Y is not indicative of malignancy and should not be considered as a marker of the malignant clone.