Gefitinib and EGFR gene copy number aberrations in esophageal cancer by Petty, RD, Dahle-Smith, A, Stevenson, DAJ, Osborne, A, Massie, D, Clark, C, Murray, GI, Dutton, SJ, Roberts, C, Chong, IY, Mansoor, W, Thompson, J, Harrison, M, Chatterjee, A, Falk, SJ, Elyan, S, Garcia-Alonso, A, Fyfe, DW, Wadsley, J, Chau, I, Ferry, DR, Miedzybrodzka, Z