We found that angiomyolipomas have very few non-synonymous exonic mutations (4 on average), and almost no recurrently mutated genes beyond TSC1 and TSC2. Although a number of genes with singleton mutations in this data set are mutated in other cancers, we suspect that most are background non-functional mutations that happened to be present in the initiating cells of these tumors, and are not tumor driver events. The gene discussed is TSC1; the disease is cancer.