The identification of cancer drivers is a major goal of current cancer research. Finding driver genes within large
chromosomal events is especially challenging because such alterations encompass many genes. Previously, we
demonstrated that zebrafish malignant peripheral nerve sheath tumors (MPNSTs) are highly aneuploid, much like human
tumors. In this study, we examined 147 zebrafish MPNSTs by massively parallel sequencing and identified both large and
focal copy number alterations (CNAs). Given the low degree of conserved synteny between fish and mammals, we reasoned
that comparative analyses of CNAs from fish versus human MPNSTs would enable elimination of a large proportion of
passenger mutations, especially on large CNAs. We established a list of orthologous genes between human and zebrafish,
which includes approximately two-thirds of human protein-coding genes. For the subset of these genes found in human
MPNST CNAs, only one quarter of their orthologues were co-gained or co-lost in zebrafish, dramatically narrowing the list of
candidate cancer drivers for both focal and large CNAs. We conclude that zebrafish-human comparative analysis represents
a powerful, and broadly applicable, tool to enrich for evolutionarily conserved cancer drivers.