JAG1 and neoplasm: We employed a subtractive WCP method for isolating human anti-AGS phage antibodies from a semisynthetic library, Tomlinson I. The selection procedure involved depletion of the library with NIH-3T3 and MKN-45 cells followed by selection on AGS cells in order to increase the likelihood of isolating antibodies that show specificity for the differentiated tumor cells.