Spontaneous regression of human acute myeloid leukaemia xenografts and phenotypic evidence for maturation.
A population of human AML cells which have a characteristic karyotypic marker was cryopreserved and then grown in short-term liquid culture for 2 weeks, during which time the cells increased about 7-fold in number and progressively acquired characteristics of macrophages. 10(7) cells obtained after 1 day in culture, when they were almost devoid of Fc receptors (Fc-), on inoculation into immune-deprived mice gave rise to tumours in more than 90% of the animals. However, after 13 days of culture, when almost all the cells had Fc receptors (Fc+), a similar inoculum did not grow as tumours. After 7 days in culture the cells were heterogeneous, and divided about equally into Fc+ and Fc- cells, both of which were replicating. The Fc- population was capable of producing tumours, whereas the Fc+ was not. Of 23 assessable xenograft tumours produced by the AML cells, 14 regressed completely, 4 grew progressively and 5 grew progressively after initial regression. Progressive tumours could be further transplanted. The regression may arise as a result of maturation in vivo similar to that seen in vitro.
D000818:Animals; D002454:Cell Differentiation; D002455:Cell Division; D002478:Cells, Cultured; D006801:Humans; D007942:Leukemia, Experimental / Q000473:pathology; D015470:Leukemia, Myeloid, Acute / Q000276:immunology / Q000473:pathology*; D008297:Male; D051379:Mice; D008808:Mice, Inbred CBA; D009365:Neoplasm Regression, Spontaneous; D009368:Neoplasm Transplantation; D011961:Receptors, Fc; D014183:Transplantation, Heterologous
D011961:Receptors, Fc