In our previous study, 14 sulfated carbohydrate tumor marker candidates were identified by focused glycomic analyses. Here, glycomic analyses focused on internally sialylated glycans to identify novel marker candidates. Internally sialylated glycans were enriched by digestion of pyridylaminated glycans prepared from sera with α-neuraminidase from Salmonella typhimurium, which did not cleave sialic acids linked to internal residues, followed by anion-exchange chromatography. Next, internally sialylated O-glycan profiles were constructed using two types of high performance liquid chromatography, which were compared between 20 healthy controls and 11 patients with gastric cancer and 9 patients with pancreatic cancer. In all, 17 marker candidates were identified. The structures of glycan candidates were precisely analyzed using enzymatic digestion, glycan synthesis, 2D mapping and mass spectrometry. Among 17 candidates, one was STn, and the other 16 comprised 10 core1, 1 core2 and 5 core3 glycans. The various structures included a α2,6-sialylated reducing terminal GalNAc and α2,6-sialylated type1 N-acetyl-lactosamine. Eight candidates possessed the Sd^a/CAD antigen. The levels of these candidate glycans in sera from all 40 subjects were quantified using a selected reaction monitoring assay and found to be elevated in at least one or more patients. Although the serum levels of each candidate glycan varied between patients, those candidates having the same backbone or determinant, such as core3 backbone and core1 structures with extended type1 N-acetyl-lactosamine, displayed similar patterns of elevation. These results suggest that analysis of multiple markers may be an effective means of diagnosing various cancers.

中文翻译：

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通过利用神经氨酸酶底物特异性的聚焦糖分析，鉴定内部唾液酸化的碳水化合物肿瘤标志物候选物，包括Sd ^a / CAD抗原

在我们先前的研究中，通过聚焦糖分析确定了14种硫酸化碳水化合物肿瘤标志物候选物。在这里，血糖分析侧重于内部唾液酸化聚糖，以鉴定新的候选标记。内部唾液酸化聚糖通过用鼠伤寒沙门氏菌的α-神经氨酸酶消化从血清中制备的吡啶基叠合的聚糖进行富集，该酶不能裂解与内部残基相连的唾液酸，然后进行阴离子交换层析。接下来，内部唾液酸化O使用两种类型的高效液相色谱法构建β-聚糖谱，在20位健康对照者和11位胃癌患者和9位胰腺癌患者之间进行了比较。总共确定了17个标记候选物。使用酶消化，聚糖合成，2D作图和质谱法精确分析了候选糖的结构。在17个候选物中，一个是STn，另外16个包含10个core1、1个core2和5个core3聚糖。各种结构包括α2，6-唾液酸化的还原末端GalNAc和α2，6-唾液酸化的1N-乙酰基-乳糖胺。八名候选人拥有Sd ^a/ CAD抗原。使用选定的反应监测测定法对来自所有40名受试者的血清中这些候选聚糖的水平进行定量，发现在至少一名或多名患者中血红蛋白水平升高。尽管每种候选聚糖的血清水平在患者之间有所不同，但具有相同骨架或决定簇（例如具有扩展的1型N-乙酰基-乳糖胺的core3骨架和core1结构）的那些候选者显示出相似的升高模式。这些结果表明，多种标记物的分析可能是诊断各种癌症的有效手段。