Structural abnormalities affecting band q13 of chromosome 11 have been reported in a variety of human tumors, particularly multiple endocrine neoplasia type 1 (MEN1), certain low-grade B-cell neoplasms, and a significant subset of breast and squamous cell carcinomas. The perturbations of the region are also varied, ranging from allele loss and deletions to specific translocations and DNA amplification. Given their clinical relevance in classifying tumors and identifying patients at increased risk, it is important to locate and characterize the genes on which these aberrations impinge. Here we assess the candidate genes identified thus far and the evidence that implicates them in tumorigenesis.