唾液酸与癌症

唾液酸是指当神经氨酸的氨基被乙醛基或羟乙酰基取代后所产生的衍生物。唾液酸位于糖蛋白或糖脂的末端,本身带负电荷,它对细胞的转运功能、细胞间的排斥反应和细胞膜上糖蛋白的合成有一定作用。在肿瘤细胞的细胞膜上其糖链唾液酸化增强,使肿瘤细胞的细胞膜上糖链混乱,并促进肿瘤细胞的转移、浸润,降低宿主对肿瘤细胞的免疫杀伤作用。唾液酸作为一种高灵敏的肿瘤标志物有大量文献报道,尽管它的特异性不高(如在炎症中其水平也增高),但唾液酸对于癌症的诊断、鉴别诊断、病情监测仍有较大临床应用价值、在血清或血浆中,有多种方法可有效测量唾液酸含量。

Sialic Acid and Cancer

The term sialic acid was used to de-scribed derivatives of neuraminic acid where its aminogroup was substituted by either an acetyl or a gly-colyl group. Location of sialic acid was at the termi-nal position. It played a role in cellular functionsuch as transportion, cell to cell repulsion and con-formation of glycoproteins on cell membranes. Howev-er, on tumor cell memberane, sialylation and sialyltransferase activity are increased. They played a rolein aberrant glycosylation in cancer cell membranes,facilitated tumor cell metastasis, decreased host defensemechanisms to cancer. The high sensitivity of sialic acidas a tumor marker has been reported in a variety of can-cers. But its specificity was relatively low since there isalso an increasing in inflammatory diseases. However, ithas value in cancer diagnosis differential diagnosis andmonitoring cancer patients during treatment. In serum andplasma there were many available methods for measure-ment of sialic acid.