[1] Chinese Univ Hong Kong, Sch Pharm, Fac Med, Hong Kong, Peoples R China
[2] Hong Kong Childrens Hosp, Dept Paediat & Adolescent Med, Hong Kong, Peoples R China
[3] St Jude Childrens Res Hosp, Epidemiol & Canc Control, Memphis, TN USA
[4] Chinese Univ Hong Kong, Dept Paediat, Hong Kong, Peoples R China