This proposal describes a 5 year mentored research project designed to transition the applicant into an independent translational scientist. During the project period, the Principal Investigator (P.I.) will devote efforts towards broadening her knowledge base and technical skills as necessary to ultimately supervise a successful laboratory based program in cancer biology. The development of the P.I. will be fostered by ongoing mentorship by an established expert in the field of cancer biology, Dr. David Solit, at an institution renowned for training clinician scientists in cancer research, Memorial Sloan-Kettering Cancer Center. To further assist with her research project and career development, the P.I. and her primary mentor have assembled a multi-disciplinary mentorship team composed of Drs. Michael Berger and William Lee, experts in genomic technology development and computational analysis, Dr. Timothy Chan, an expert in epigenomics, Dr. Leonard Saltz, Chief of the Gastrointestinal Oncology Service, Martin Weiser, Associate Member of the GI Surgical Oncology Service, and David Klimstra, Chair of the Department of Pathology. The focus of the applicant's research is the biological characterization of matched primary colorectal carcinomas (CRC) and metastases. In Aim 1, we will use a novel bait-capture, next generation sequencing assay to define the mutational status of 300 cancer associated genes in 100 primary CRC and matched metastases. Matched pairs that show discordant mutational profiles between the primary tumor and the metastasis will be further analyzed using the same bait-capture, next generation sequencing assay, to sequence multiple areas of the primary tumor and metastasis in order to determine whether discordance when present can be attributed to intratumoral genetic heterogeneity. Whole genome analysis will be performed in a select subset of cases. In Aim 2, we will focus on tumor suppressor genes that are found in Aim 1 to be more commonly mutated in the metastatic lesions versus their corresponding primary tumors. These genes will be studied for differences in methylation patterns and protein expression levels. In Aim 3, we will study discordant alterations identified in Aim 1 to determine whether they have a functional role in invasion or metastasis. In these functional studies, we will use isogenic CRC cell lines to assess the effects of gene mutations on cell migration and invasion. Genes will then be further studied in vivo using a tail vein injection tumor metastasis model system. The overall goal of these studies is to define the extent of genetic and epigenetic heterogeneity in metastatic CRC and to identify genetic alterations that drive disease progression in colorectal cancer patients, thus, aiding in the identification of novel therapeutic strategies for this disease.