China will build the world's largest bone marrow bank for Chinese patients with 500,000 samples in seven years, a senior official of the Red Cross Society of China announced yesterday. 'Once the bank is completed, most overseas Chinese in need of a bone marrow transplant will be able to find their match from the bank,' said Wang Lizhong, the society's vice-president. Mr Wang said the Chinese government had allocated 330 million yuan (HK$311 million) to the society for the project. At present, the marrow bank in China only has about 50,000 samples. The United States has the world's biggest marrow bank with 4.6 million samples. Officials said the project would be divided into two phases. The first phase, which will be completed by 2004, will expand the marrow bank's samples to 100,000. The second phase will be completed in 2009. Bone marrow transplant is currently the most effective cure for blood diseases such as leukaemia and serious anaemia. According to Xinhua, mainland leukaemia sufferers are increasing by about 40,000 a year and some 50,000 people die annually from the disease. The majority of the victims are children. One major reason behind the high fatality rate is the lack of suitable donors. Lu Diao from the Chinese Academy of Sciences told Xinhua that China urgently needed an established bone marrow bank because Chinese leukaemia patients have a difficult time finding donors who have the same human leucocyte antigen (HLA) - genetic markers on white blood cells - compared to other races. According to Professor Lu, the chance of finding a suitable bone marrow among a patient's brothers and sisters is only 25 per cent. At present, China only has 100,000 volunteers who have offered to donate their bone marrow. The expanded marrow bank would also benefit Chinese patients who live outside China because they often have difficulties in finding suitable marrow matches in foreign banks. The Hong Kong Marrow Match Foundation and Taiwan's Tzu Chi Foundation - a Buddhist charity group - have co-operated with their mainland counterparts in the past. Since 1993, the Tzu Chi Foundation has arranged more than 80 marrow transplants in China with samples given by Taiwanese donors. Mainland officials hope that the expanded bone marrow bank will encourage more people to volunteer as donors.