Epidemiology and hereditary aspects of acute leukemia

Recent projections for the USA estimate that 6590 patients are diagnosed annually with acute lymphocytic leukemia (ALL) and 19,950 with acute myeloid leukemia (AML), while approximately 1430 patients die from ALL and 10,430 from AML (Siegel et al., CA Cancer J Clin 66(1):7-30, 2016). Together these forms of acute leukemia represent about 1.6% of all newly diagnosed cancers and 2.0% of all cancer deaths in the USA (Siegel et al., CA Cancer J Clin 66(1):7-30, 2016). Advances in the understanding of immunology and molecular/genetic features of the acute leukemias along with laboratory improvements in immunophenotyping and cytogenetic characterization have led to the recognition of molecularly defined subtypes of ALL and AML, targeted therapeutics, and recognition of distinct prognostic groups. The most recent World Health Organization (WHO) classification of hematopoietic malignancies considers three major categories of acute leukemia: AML and related myeloid precursor neoplasms, precursor lymphoid neoplasms (encompassing the entities previously known as ALL), and acute leukemias of ambiguous lineage (World Health Organization classification of tumours of haematopoietic and lymphoid tissues, 4th ed. Lyon: International Agency for Research on Cancer, 2008). Consistent with classifications used in cancer registries, to date most epidemiologic investigations have considered all acute leukemias combined or the broad categories of ALL and AML, although an increasing number of studies, especially those of genetic risk factors, examine cases by molecular subtype. Traditionally pediatric acute leukemias, defined either as those diagnosed at 0-14 or 0-19 years of age, have been studied separately from that in adults.