The following message of the authors has been received July 28, 2008:

Dear Professor Hengstler,

we request to withdraw this review because of the first author's mistake in English writing and reference citation improperly. We apologize for inconvenience to the Journal editors and readers.

Yours sincerely,

Daiming Fan

Director & Professor
State Key Laboratory of Cancer Biology & Institute of Digestive Diseases
Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, P.R.China
Tel: 86-29-84775221
Fax: 86-29-82539041
E-mail: fandaim@fmmu.edu.cn