The introduction of next-generation sequencing technologies has dramatically impacted the life sciences, perhaps most profoundly in the area of cancer genomics. Clinical applications of next-generation sequencing and associated methods are emerging from ongoing large-scale discovery projects that have catalogued hundreds of genes as having a role in cancer susceptibility, onset and progression. For example, discovery cancer genomics has confirmed that many of the same genes are altered by mutation, copy number gain or loss, or structural variation across multiple tumor types, resulting in a gain or loss of function that likely contributes to cancer development in these tissues. Beyond these frequently mutated genes, we now know there is a 'long tail' of less frequently mutated, but probably important, genes that play roles in cancer onset or progression. Here, I discuss some of the remaining barriers to clinical translation, and look forward to new applications of these technologies in cancer care.