Features Editors: Paris: Kate Millar +33 1 4041 4636 Hong Kong: Liz Thomas +852 2829 6211 Twitter: @AFPfeature We are offering the following item: + Europe's guardian of stem cells and hopes, real and unrealistic Poland-health-biotechnology-Switzerland,FEATURE WARSAW Poland has emerged as Europe's leader in stem cell storage, a billion-dollar global industry that is a key part of a therapy that can treat leukaemias but raises excessive hopes. 950 words by Michel Viatteau. Pictures by Wojtek Radwanski. Video by Damien Simonart afp