Cytogenetics of Preleukemic Stages in Experimental and Human Leukemogenesis

Abstract

The accessibility of tissue material for diagnostic purposes is an important factor in the early diagnosis of cancer. The human bone marrow as the site of interest in leukemia research is generally considered as accessible. Nevertheless, our knowledge about the early stages of leukemia is sparse. This has several reasons: One is that leukemia is a rare disease; another is that symptoms can develop rather late after the manifestation of the disease; finally, screening programs for populations at risk are nonexistent and even the definition of populations at risk is an unsolved problem. These populations are rather large in view of the expense of the studies needed, and the final incidence of leukemia is too low — benzene-exposed people, patients after Thorotrast (see Seidel 1978), now the population exposed at Chernobyl. For the study of early phases of the leukemogenic process animal models have to be used; they are readily available. A further consideration has to be that leukemic cells, at least in small numbers, are not easy to identify. A proper marker would help and many workers in immunology or molecular research are investigating this problem. We will discuss the presence of abnormal karyotypes in hemopoietic cells as markers of an abnormal cell proliferation which may be itself leukemic or on the way to an expanding malignant population.