Accession Numbers
The whole-genome sequencing data reported in this paper have been deposited in the European Genome-phenome Archive under EGA: EGAD00001004088 as a subset of the NIHR BioResource Rare Disease Consortium data.

Web Resources
ClinVar, https://www.ncbi.nlm.nih.gov/clinvar/
Ensembl, http://www.ensembl.org
European Genome-phenome Archive, https://ega-archive.org/
ExAC Browser, http://exac.broadinstitute.org/
GenBank, https://www.ncbi.nlm.nih.gov/genbank/
OMIM, https://www.omim.org/
UCSC Genome Browser, https://genome.ucsc.edu/

Supplemental Data
Document S1. Figures S1 and S2 and Tables S2 and S7
Table S1. Tumor Categorization and Frequency in Series
Table S3. Full and Filtered Gene List
Table S4. American College of Medical Genetics Criteria as Applied to SNV and Indel Analysis
Table S5. Tumor Combinations in Series
Table S6. Filtered SNVs and Indels Deemed Pathogenic or Likely Pathogenic by ACMG Assessment and Structural Variants Passing Filtering Steps
Document S2. Article plus Supplemental Data

Acknowledgments
J.W. is supported by a Clinical Research Training Fellowship from the Cancer Research UK Cambridge Cancer Centre. Funding for the National Institute for Health Research (NIHR) BioResource Rare Diseases project was provided by the NIHR (grant number RG65966). E.R.M. acknowledges support from the European Research Council (Advanced Researcher Award), the NIHR (Senior Investigator Award and Cambridge NIHR Biomedical Research Centre), the Cancer Research UK Cambridge Cancer Centre, and the Medical Research Council (Infrastructure Award). The University of Cambridge has received salary support for E.R.M. from the National Health Service (NHS) in the East of England through the Clinical Academic Reserve. The views expressed herein are those of the authors and not necessarily those of the NHS or the Department of Health. D.G.E. is an NIHR Senior Investigator and is supported by the NIHR Manchester Biomedical Research Centre. Supplemental Data include two figures and seven tables and can be found with this article online at https://doi.org/10.1016/j.ajhg.2018.04.013.