Variation of plasma free amino acids (PFAAs) is an essential feature of protein metabolic abnormalities in cancer patients. But there still little data about the cancer tissue free amino acid (TFAAs) profiles, including their patterns and correlations with PFAAs. To evaluate the variation in PFAAs and cancer TFAAs in patients with lung cancer, including their patterns and correlations, we investigated the concentrations of free amino acids in lung cancer tissues (n=27), paired lung paracarcinomous tissues (n=27) and plasma (n=27) using an automatic amino acid analyzer after pre-treatment. Within the PFAAs, the concentrations of five amino acids (tryptophan, glycine, citrulline, ornithine and proline) were significantly decreased, while that of phenylalanine was markedly increased compared with control subjects. Within the TFAAs, the concentrations of three amino acids (taurine, glutamic acid and glycine) were increased, while the concentrations of two amino acids (lysine and ornithine) were decreased significantly in lung cancer tissues compared with the paracarcinomous tissues. The amino acid patterns in PFAAs and TFAAs had similar trends, but percentage variations were diverse. Additionally, the concentrations of five amino acids (lysine, phenylalanine, threonine, serine, and alanine) in PFAAs correlated with those in lung cancer TFAAs, but no amino acids in PFAAs were correlated with those in lung paracarcinomous TFAAs. Thus, PFAA profiles may reflect the status of cancer tissues, which may provide more information about the metabolic statuses and prognoses of patients with lung cancer.
肿瘤病人体内血浆游离氨基酸变化是其蛋白质代谢异常的一个基本特征。但是 目前很少有研究关注肿瘤组织内部的氨基酸情况，包括它们的模式以及与血浆 氨基酸的浓度相关性。为了评价肺癌病人血浆和肿瘤组织中游离氨基酸的变化 情况，我们使用氨基酸分析仪测定了27 位肺癌肿瘤病人治疗前的血浆、肿瘤 组织以及癌旁组织中的游离氨基酸浓度。跟正常人血浆游离氨基酸浓度相比 较，我们发现肿瘤病人血浆游离氨基酸浓度中色氨酸、甘氨酸、瓜氨酸、鸟氨 酸和脯氨酸显著下降，而蛋氨酸显著上升；与癌旁组织相比，牛磺酸、谷氨酸 和甘氨酸浓度显著增加，而赖氨酸和鸟氨酸浓度显著下降。在血浆和组织中游 离氨基酸有相似的浓度趋势，但是百分比变化是各异的。另外，我们发现血浆 和肺癌组织中的赖氨酸、蛋氨酸、苏氨酸、丝氨酸和丙氨酸有浓度相关性，但 是在血浆中和癌旁组织中没有发现一种氨基酸具有浓度相关性。因此，血浆游 离氨基酸变化可能反应了肿瘤组织中氨基酸水平，这或许会对肺癌病人未来的 代谢状态和预后提供更多信息。