We made use of a new monoclonal antibody recently developed in our laboratory, 1G6-D7, which recognizes the F-5 fragment of Hsp90α and strongly neutralizes the tumour-secreted Hsp90α function (Zou, M., Dong, H., Bhatia, A., Jayaprakash, P. and Li, W. unpublished). This evidence concerns the gene HSP90AA1 and neoplasm.