【中文版】

AFP是甲胎蛋白，是一种糖蛋白，正常情况下，这种蛋白主要来自胚胎的肝细胞。在成人中，AFP可以在正常肝细胞和生殖腺胚胎细胞中表达，但通常在周围血液中含量很低。AFP在肝癌中的表达水平会显著升高，因此AFP是诊断肝癌的重要指标之一。

AFP在肝癌中的表达水平可以用来判断肝癌的恶性程度和预后。一般来说，AFP越高，肝癌的恶性程度越高，预后越差。因此，AFP是肝癌治疗和监测的重要指标之一。

除了肝癌，AFP还可以在其他疾病中表达异常。例如，在一些生殖腺胚胎肿瘤和病毒性肝炎中，AFP的表达水平也可能升高。因此，AFP的检测不仅可以用于诊断肝癌，还可以为其他疾病的诊断和治疗提供参考。

总的来说，AFP是一种重要的肿瘤标志物，可以用于诊断肝癌和其他疾病。在临床实践中，医生通常会结合患者的病史和其他检查指标来判断AFP的表达水平是否具有诊断价值。

【英文版】

AFP is alpha-fetoprotein, a kind of glycoprotein. Under normal circumstances, this protein mainly comes from hepatocytes of embryos. In adults, AFP can be expressed in normal liver cells and germ cells, but it is usually low in peripheral blood. The expression level of AFP in liver cancer can significantly increase, so AFP is an important index for diagnosing liver cancer.

The expression level of AFP in liver cancer can be used to determine the degree of malignancy and prognosis of liver cancer. Generally speaking, the higher the AFP level, the higher the malignancy degree of liver cancer and the worse the prognosis. Therefore, AFP is an important index for the treatment and monitoring of liver cancer.

In addition to liver cancer, AFP can also express abnormally in other diseases. For example, in some germ cell tumors and viral hepatitis, the expression level of AFP may also increase. Therefore, AFP detection can not only be used for diagnosing liver cancer, but also provide reference for the diagnosis and treatment of other diseases.

In summary, AFP is an important tumor marker that can be used to diagnose liver cancer and other diseases. In clinical practice, doctors usually combine the patient's medical history and other examination indexes to determine whether the expression level of AFP is diagnostic.