摘要AIM:To investigate the prognostic value of chromosome 18q microsatellite alterations (MA) in stage Ⅱ colon cancer.METHODS:One hundred and six patients with sporadic stage Ⅱ colon cancer were enrolled in this study.DNA was extracted from formalin-fixed,paraffin-embedded tumor and adjacent normal mucosal tissue samples.MA,including loss of heterozygosity (LOH) and microsatellite instability (MSI),was analyzed by polymerase chain reaction,polyacrylamide gel-electrophoresis and DNA sequencing at 5 microsatellite loci on chromosome 18q (D18S474,D18S55,D18S58,D18S61 and D18S64).RESULTS:Among the 102 patients eligible for MA information,the overall frequencies of LOH,high and low frequency MSI/microsatellite stable were 49.0%,17.6%and 82.4%,respectively.The high frequency of 18q-LOH was significantly associated with the poor 5-year overall survival (OS) (P = 0.008) and disease free survival (P =0.006).High levels of MSI were significantly associated with a longer 5-year OS (P = 0.045) while the higher frequency of 18q-LOH at the loci of D18S474 and D18S61.was significantly associated with a poorer 5-year OS (P= 0.010 and 0.005,respectively).But multivariate analysis showed that only the frequency of 18q-LOH was significantly associated with the prognosis of the disease.CONCLUSION:High frequency of 18q-LOH is an independent prognostic factor indicating poor prognosis of the patients with stage Ⅱ colon cancer.