Schauenstein E, Rabl H, Steinschifter W, Hirschmann C, Estelberger W, Schauenstein K
Department of Biochemistry, University of Graz, Austria.
Cancer. 1997 Apr 15;79(8):1482-6.
Malignant diseases of various origins were previously shown to be associated with a characteristic and highly significant change in the serum pattern of immunoglobulin (Ig)G subclasses, comprised of a decrease in %IgG1 and an increase in %IgG2 relative to and independent of the absolute concentration of total IgG. The goal of the current study was to evaluate this phenomenon as an indirect marker in the primary diagnosis of colorectal carcinoma.
Using affinity chromatography, IgG1, IgG2, and total IgG were determined in 36 patients with colorectal carcinoma of different stages and compared with 162 apparently healthy controls.
It was found that: 1) the mean values for %IgG1 and %IgG2 of all carcinoma patients differed significantly from those of the controls; 2) no quantitative association was found with tumor stages, and four of five patients with incipient adenocarcinoma within a polyp exhibited the characteristic shift in IgG subclasses; 3) based on a calculated cutoff, the specificity and sensitivity of %IgG1 to discriminate between controls and carcinoma patients was found to be 88% and 74%, respectively; and 4) a quantitative correlation between individual %IgG1 values and the probability of correct assignment to carcinoma patients or controls was established.
The significant decrease in %IgG1 accompanied by an increase in %IgG2 in total serum IgG represents an indirect, tissue nonspecific, and early marker of malignant proliferation that distinguishes colorectal carcinoma patients from healthy controls with a specificity of 88% and sensitivity of 74%.
先前研究表明，各种起源的恶性疾病与血清免疫球蛋白（Ig）G亚类模式的特征性且高度显著变化相关，表现为相对于总IgG绝对浓度且与之无关的IgG1百分比降低和IgG2百分比升高。本研究的目的是评估这种现象作为结直肠癌初步诊断的间接标志物。
采用亲和色谱法测定36例不同分期的结直肠癌患者的IgG1、IgG2和总IgG，并与162名明显健康的对照者进行比较。
发现：1）所有癌症患者的IgG1百分比和IgG2百分比平均值与对照组有显著差异；2）未发现与肿瘤分期有定量关联，息肉内早期腺癌的五名患者中有四名表现出IgG亚类的特征性变化；3）根据计算出的临界值，发现IgG1百分比区分对照者和癌症患者的特异性和敏感性分别为88%和74%；4）建立了个体IgG1值与正确归类为癌症患者或对照者概率之间的定量相关性。
血清总IgG中IgG1百分比显著降低伴IgG2百分比升高，代表了一种间接的、组织非特异性的恶性增殖早期标志物，可将结直肠癌患者与健康对照者区分开来，特异性为88%，敏感性为74%。
