Sani B P, Condon S M, Brockman R W, Weiland L H, Schutt A J
Cancer. 1980 Mar 15;45(5 Suppl):1199-206. doi: 10.1002/1097-0142(19800315)45:5+<1199::aid-cncr2820451326>3.0.co;2-d.
Retinoic acid-binding protein is present in metastatic murine colon tumors as well as in Lewis lung tumors and in lungs and brains of mice bearing these tumors; however, this protein is below the limits of detection in weakly-metastatic carcinomas and in normal lung, colon, or brains. These observations are interesting since they concern the possibility of measuring the binding protein levels of colon tumors in clinical specimens as biochemical markers in human malignancy. A total of thirty-three human colon tumors and related materials were analyzed for the presence of the binding protein. The interfering serum albumin, which nonspecifically binds retinoic acid, was eliminated by affinity chromatography. Of the twenty colon, cecum, and rectum tumors analyzed, 80% contained the binding protein in detectable amounts, and 20% showed nondetectable or marginally detectable amounts. Twenty-two percent of the human colon segments isolated from patients suspected for colon tumors contained the binding protein in readily detectable amounts, whereas 78% revealed nondetectable to marginally detectable amounts. The retinoic acid-binding protein of human colon tumor shared the same ligand specificity, thiol functions in ligand-binding, and sedimentation coefficient as the binding protein isolated from chick embryo skin. However, the human protein exhibited altered isoelectric pH.
视黄酸结合蛋白存在于转移性小鼠结肠肿瘤、Lewis肺癌以及携带这些肿瘤的小鼠的肺和脑中；然而，在低转移性癌以及正常肺、结肠或脑中，这种蛋白低于检测限。这些观察结果很有意思，因为它们涉及在临床标本中测量结肠肿瘤结合蛋白水平作为人类恶性肿瘤生化标志物的可能性。总共对33份人类结肠肿瘤及相关材料进行了分析，以检测结合蛋白的存在。通过亲和层析消除了非特异性结合视黄酸的干扰性血清白蛋白。在分析的20份结肠、盲肠和直肠肿瘤中，80%含有可检测量的结合蛋白，20%显示不可检测或勉强可检测的量。从疑似患有结肠肿瘤的患者中分离出的22%的人类结肠段含有易于检测到的结合蛋白量，而78%显示不可检测到勉强可检测的量。人类结肠肿瘤的视黄酸结合蛋白与从鸡胚皮肤分离出的结合蛋白具有相同的配体特异性、配体结合中的硫醇功能以及沉降系数。然而，人类蛋白的等电pH值有所改变。
