Construction of Evaluating system of serum markers for Gastric Cancer.

截至1994年底，共收集胃癌病例735例，对照组1005例。检测受试者血清胃蛋白酶原I、II和血清抗幽门螺杆菌IgG抗体。剩余血清保存在-80ºC。采用ROC （Receiver Operator characteristic）曲线对6个年龄-性别组进行胃癌诊断，寻找血清胃蛋白酶原的最佳截断值。<<表>>敏感性和特异性与年龄呈负相关，但没有年龄-性别分组，在大规模筛查中具有足够的实际应用价值。分析中部分患者为无法治愈的晚期癌症，应将患者限定在可治愈的癌症中进行精确分析，以便最终评估血清胃蛋白酶原。当两种或两种以上标记物同时使用时，还应寻找最佳的灵敏度和特异性。计算5个年龄组胃癌与血清抗幽门螺杆菌抗体阳性之间的比值比（OR）。20 ~ 29岁的OR为23.1,30 ~ 39岁为11.0,40 ~ 49岁为9.6,50 ~ 59岁为3.3,60 ~ 69岁为1.6。

Until the end of 1994,735 gastric cancer cases and 1005 controls were collected. As for the subjects, serum pepsinogen I,II and serum anti-Helicobacter pylori IgG antibody were measured. The residual sera habe been stored at -80ﾟC.Optimum cut off values of serum pepsinogen for diagnosis of gastric cancer were searched for by ROC (Receiver Operator Characteristics) curve regarding 6 age-sex groups.<<table>>The sensitivity and specificity were negatively related to age, but for no age-sex group, adequate value for practical use in mass-screening was obtained. Some of the patients in the analysis were incurable advanced cancer and precise analysis should be done limiting the patients to those with curable cancer in order to evaluate serum pepsinogen finally. Optimum sensitivity and specificity when two or more markers are used together should also be searched for.Odds ratios (OR) for the association between gastric cancer and seropositivity of anti-Helicobacter antibody were calculated regarding 5 age groups. For those aged 20-29 years, OR was 23.1, for 30-39 it was 11.0, for 40-49 it was 9.6, for 50-59 it was 3.3 and for 60-69 it was 1.6.