High cobalamin levels have previously been associated with short-term cancer risk, including lung cancer. We explored whether levels of cobalamin and/or its binding proteins are useful as a diagnostic tool in patients suspected of non-small cell lung cancer. We included 889 patients referred for fast-track diagnosis of lung cancer to Aarhus University Hospital, Denmark. We analyzed plasma concentrations of cobalamin, transcobalamin, holotranscobalamin and haptocorrin. Information on lung cancer diagnosis was retrieved from a national database. The study cohort showed levels above reference intervals for cobalamin 12%, holotranscobalamin 25%, transcobalamin 9% and haptocorrin 36% (all p-values <.05). We observed no difference in cobalamin or holotranscobalamin levels when comparing patients diagnosed with non-small cell lung cancer (n = 161, 18%) to patients without lung cancer (n = 742, 80%), while transcobalamin showed minor differences. Haptocorrin was significantly higher in those with cancer, mainly among patients with adenocarcinoma (n = 94). A comparison of patients with the highest vs. lowest quartile levels of haptocorrin yielded an adjusted odds ratio for adenocarcinoma of 2.39 (95% confidence interval: 1.26-4.55). However, ROC curve analyzes showed haptocorrin (AUC = 0.55) and total transcobalamin (AUC = 0.56) to be poor diagnostic markers for lung cancer. A high proportion of patients suspected for non-small cell lung cancer showed increased levels of cobalamin-binding proteins. We thereby confirm the association between non-small cell lung cancer and high cobalamin levels and found that haptocorrin was the major underlying factor causing high cobalamin levels. However, none of these biomarkers were of diagnostic use among patients referred for suspected lung cancer.

中文翻译：

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非小细胞肺癌患者的维生素B12及其结合蛋白被称为肺癌的快速诊断方法。

钴胺素水平高以前与包括肺癌在内的短期癌症风险有关。我们探讨了钴胺素和/或其结合蛋白的水平是否可用于怀疑非小细胞肺癌患者的诊断工具。我们纳入了889例因肺癌的快速诊断而被转诊至丹麦奥尔胡斯大学医院的患者。我们分析了钴胺素，反式钴胺素，全反式钴胺素和haptocorrin的血浆浓度。从国家数据库中检索到有关肺癌诊断的信息。该研究队列显示钴胺素12％，全反钴胺素25％，反钴胺素9％和触铁连蛋白36％高于参考区间（所有p值<.05）。在比较被诊断为非小细胞肺癌的患者时（n = 161，18％）未患肺癌的患者（n = 742，80％），而转钴胺素显示出较小的差异。肝癌患者的肝素含量显着更高，主要在腺癌患者中（n = 94）。比较最高或最低四分位数的结合蛋白的患者，腺癌的校正比值比为2.39（95％置信区间：1.26-4.55）。但是，ROC曲线分析显示，触角结合蛋白（AUC = 0.55）和总反钴胺素（AUC = 0.56）是肺癌的不良诊断标记。怀疑患有非小细胞肺癌的患者中，有很大比例的钴胺素结合蛋白水平升高。因此，我们证实了非小细胞肺癌与高钴胺素水平之间的关联，并发现haptocorrin是引起高钴胺素水平的主要潜在因素。然而，