A VACCINE that could deal a serious blow to seven in 10 lethal cancers has been developed by scientists.

In tests, it shrank breast tumours by 80 percent and researchers believe it could also tackle prostate, pancreatic, bowel and ovarian cancers.

Even tumours that resist treatment with the best medicines on the market, including the "wonder drug" Herceptin, may be susceptible to the vaccine.

The experiments so far have been on mice - but researchers hope to pilot the drug on people within two years. If all goes well, the vaccine could be on the market by 2020.

Rather than attacking cancer cells, like many drugs, the new treatment harnesses the power of the immune system to fight tumours.

The search for vaccines has been hampered by fears that healthy tissue would be destroyed along with tumours.

Researchers from the University of Georgia and the Mayo Clinic in the US focused on a protein called MUC1 that is made in bigger amounts in cancerous cells than in healthy ones.

Not only is there more of it, but a sugar that it is "decorated" with has a distinctive shape.

The vaccine trains the immune system to recognise the rogue sugar and turn its arsenal against the cancer.

"Cancer cells have a special way of thwarting the immune system by putting sugars on the surface of tumour cells so they can travel around the body without being detected," researcher Professor Sandra Gendler said.

"To enable the immune system to recognise the sugar it took a special vaccine that had three parts to it."

She said it was this that "turned out to be a winning combination".
科学家研发出一种疫苗，可有力地抗击70%的致命癌症。

在试验中，这种疫苗让乳腺肿瘤缩小了80%，研究人员认为该疫苗还能治疗前列腺癌、胰腺癌、肠癌和卵巢癌。

就算是市面上药物（包括治疗乳腺癌的“万灵药”赫赛汀）也无法治疗的肿瘤，可能也会屈服于这种疫苗的威力。

到目前为止该疫苗的试验都是在老鼠身上进行的，不过研究人员希望能在两年内将该药物在人身上做小规模试验。如果一切进展顺利，这一疫苗可能将于2020年上市出售。

这种新疗法并不是像其他许多药物一样抗击癌细胞，而是调动免疫系统的力量来对抗肿瘤。

一直以来寻找癌症疫苗最担心的问题，是在摧毁肿瘤细胞的同时，会把健康组织也破坏掉。

来自乔治亚大学和美国梅奥诊所的研究人员将目光聚焦于一种名为MUC1的蛋白质，这种蛋白质在癌细胞中的数量比在健康细胞中的数量大。

这种蛋白质不仅在癌细胞中数量更多，而且这种蛋白质的周边还“点缀”着一种形状独特的糖类物质。

这种疫苗能“训练”免疫系统，让其能够识别这种“恶糖”，并将攻击的矛头转而指向癌症。

研究人员桑德拉•贞德勒教授说：“癌细胞用糖包裹住肿瘤细胞，这样癌细胞就可以在体内到处游走而不被察觉，通过这种特殊的方式来阻挠免疫系统的抗击。

“为了让免疫系统能够识别这种糖，我们需要一种特殊的疫苗，这种疫苗由三个部分组成。”

她说，这种疫苗“经证实是成功的组合”。

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