Wu A H, Sell S
University of Texas Medical School, Houston.
Immunol Ser. 1990;53:403-22.
Markers for hepatocellular cancer include the best and worst of cancer detection. Although hepatocellular cancer is relatively infrequent compared to other cancers in the western world, HCC has a very high incidence in parts of Asia and Africa. It is estimated to be one of the most common cancer worldwide. High risk factors for HCC include previous hepatitis B infection, heavy alcohol consumption, cirrhosis, and aflatoxin exposure. Alpha fetoprotein may be the best human cancer marker that appears in the serum, but levels of this marker are often not elevated until the tumor is beyond surgical treatment. No other serum or tissue marker is particularly useful. Screening of high-risk populations in China has detected previously undiagnosed HCC in 1,000 of 5 million individuals tested and has led to an increase in survival from 5.5 to 61.6% with surgical resection over those who are later diagnosed with HCC without screening. Elevations of AFP due to yolk sac tumors may be differentiated from those due to HCC on the basis of Concanavalin A reactivity. Immunodetection using radiolabeled anti-AFP and immunoscintigraphy have given inconsistent results that are not as sensitive as ultrasonography in detecting HCC in the liver. Various enzymes, isoenzymes, and other markers may be useful as adjuncts to diagnosis in selected cases, but are not generally as good as AFP alone. If a patient has an AFP-producing tumor, the serum levels of AFP provide an excellent means of monitoring its progression. If the serum AFP levels drop to normal and stay there, cure is almost certain. If, however, the serum AFP level does not fall at the normal catabolic rate after therapy, or subsequently rises, regrowth of metastases are indicated. Immunotherapy using anti-AFP has not been shown to induce remission, but experimental studies indicate that drug-conjugated anti-AFP is effective in inhibiting growth of AFP-producing tumors. Clinical trials using drug-conjugated anti-AFP are now underway. Monoclonal antibodies have not yet identified the "antigens" useful for the diagnosis or treatment of HCC, but epitopes identified by monoclonal antibodies have been studied experimentally in rats which indicate multiple cellular lineages to HCC in cases of experimental chemically induced hepatocarcinoma.
肝细胞癌的标志物体现了癌症检测中最好和最差的情况。尽管在西方世界，肝细胞癌相较于其他癌症相对少见，但在亚洲和非洲部分地区，肝癌的发病率却非常高。据估计，它是全球最常见的癌症之一。肝癌的高危因素包括既往乙肝感染、大量饮酒、肝硬化以及黄曲霉毒素暴露。甲胎蛋白可能是出现在血清中的最佳人类癌症标志物，但通常直到肿瘤无法进行手术治疗时，该标志物水平才会升高。没有其他血清或组织标志物特别有用。在中国，对高危人群进行筛查，在500万受检个体中发现了1000例此前未被诊断出的肝癌患者，并且与那些未经过筛查而后来被诊断出肝癌的患者相比，手术切除后的生存率从5.5%提高到了61.6%。卵黄囊瘤导致的甲胎蛋白升高可根据伴刀豆球蛋白A反应性与肝癌导致的甲胎蛋白升高相区分。使用放射性标记的抗甲胎蛋白进行免疫检测以及免疫闪烁造影所得到的结果并不一致，在检测肝脏中的肝癌时不如超声检查敏感。各种酶、同工酶和其他标志物在某些特定病例中可能作为诊断辅助手段有用，但总体上不如单独使用甲胎蛋白。如果患者患有产生甲胎蛋白的肿瘤，血清中甲胎蛋白水平为监测其进展提供了极佳的手段。如果血清甲胎蛋白水平降至正常并保持在正常水平，几乎可以确定已治愈。然而，如果治疗后血清甲胎蛋白水平未以正常分解代谢速率下降，或者随后升高，则表明有转移灶复发。使用抗甲胎蛋白的免疫疗法尚未显示能诱导缓解，但实验研究表明，药物偶联的抗甲胎蛋白在抑制产生甲胎蛋白的肿瘤生长方面有效。目前正在进行使用药物偶联抗甲胎蛋白的临床试验。单克隆抗体尚未确定对肝癌诊断或治疗有用的“抗原”，但单克隆抗体识别出的表位已在大鼠中进行了实验研究，这表明在实验性化学诱导肝癌病例中，肝癌存在多个细胞谱系。
