恶性肿瘤已跃居中国农村与城市居民死因第一位。从分子水平上看,肿瘤是由于细胞在致癌因素的影响下发生基因突变,失去对生长的正常调控而导致的单克隆性异常增生所致。随着分子生物学技术的迅猛发展,不仅肿瘤组织,其他临床标本如血浆[1]、穿刺液[2]、尿液[3]、粪便[4]等均能检测出肿瘤源性 Malignant tumor has leapt to China’s rural areas and urban residents the first cause of death. At the molecular level, the tumor is due to cell mutations in the gene under the influence of carcinogenic factors, loss of normal regulation of growth caused by the monoclonal abnormal proliferation. With the rapid development of molecular biology technology, not only tumor tissue, but also other clinical samples such as plasma [1], puncture fluid [2], urine [3], stool [4]