定量分析胃粘膜不典型增生MC_5抗原表达及高危界值探讨

Quantitative analysis of MC_5 antigen in gastric mucosal dysplasia and its high risk cut off value

目的：探讨MC5表达状况与癌变关系。方法：应用抗结肠癌单克隆抗体MC5及ABC免疫组化染色检测了64例具有随访结果的胃粘膜异型增生标本，用计算机图象分析系统对MC5抗原的表达进行了定量分析，通过计算约登指数及绘制ROC曲线探讨了高危界值．结果：64例标本中，癌变组30例，未癌变组34例，随访时间6～72个月（平均26个月）。结果：MC5肿瘤抗原在判定不典型增生是否具有癌变倾向的灵敏度（Se）＝66．7％，特异度（Sp）＝76.5％，总符合率（准确度）＝71．9％，阳性似然比＝2．84，阴性似然比＝0．44．图象分析结果胃粘膜异型增生标本平均灰度≥0．22为高危界值。结论：上述研究将为进一步建立胃粘膜癌变概率的判别模式提供资料。

Objective: To discuss the relationship between expression of MC5 and gastric cancer. Methods: By using ABC immunohistochemical method, we studied the expression of MC5Ag in 64 cases of gastric mucosal dysplasia which had been followed-up for an average of 26 months.Furthermore, quantitation analysis of MC5Ag was taken by digital imaging analysis computer program, and the cut off value of high risk of dysplasia was also appraised through operating Youden's Index (Y1) and drawing receiver operation characteristic curve (ROC). Results: Among the 64 cases of dysplasia, 30 were found to have cancer, and 34 no cancer, the duration of following-up period was 6~72 months (average 26 months). Positive expression of MC5Ag was found in 20 out of 30 cases with cancer, and in 8 out of 34 with out cancer. The sensitivity (Se) was 66.7 %, and specificty (Sp) 76.5 %, the accuracy rate was 71.9%, the positive likelihood ratio (+LR)was 2.84, and negative likelihood ratio (-LR) 0.44, The high risk cut off value of dysplasia was 0.22.Conclusions: These findings suggest that the positive expression of MC5Ag may be a good marker to distinguish whether there is tendency of gastric mucosal dysplasia developing into early cancer.Carefuy follow-up study of these patients, in particular, the average grey density≥0.22, may be an early sign of gastric cancer.