The invention relates to linkers and methods for generating arrays with linkers. The invention also relates to methods for identifying agents that bind to various types of molecules on the arrays and to defining the structural elements of the molecules on the arrays that bind to those agents. The arrays and methods provided herein may be used for epitope identification, drug discovery and as analytical tools. The invention provides useful glycans and epitope determinants that are useful in detecting, diagnosing, recurrence monitoring and preventing cancer.