Shalitin C, Epelbaum R, Valansi C, Segal R, Mekori T, Lover B, Robinson E
Department of Biology, Technion-Israel Institute of Technology, Haifa.
Int J Cancer. 1991 Dec 2;49(6):861-6. doi: 10.1002/ijc.2910490610.
A novel 21-kDa protein (p21) was isolated from auto-immune complexes, found in sera of 14 patients with malignant urogenital tumors and isolated on Protein A-Sepharose. Isolated complexes were analyzed in 15% polyacrylamide-SDS minigels. After staining with Coomassie blue R, the bands were scanned with a clinical densitometer. The level of p21 in sera of cancer patients was 3 times higher than that found in normal individuals. An attempt was made to correlate consecutive levels of p21 in the sera of these cancer patients with the clinical course. In 4 cases a significant decrease (57-75%) in the level of p21 was observed in parallel with response to treatment. In 9 of 10 cases where no response or tumor progression was observed, the relative abundance of p21 increased or remained unchanged. Thus, the level of p21 was indicative of progression or regression of the disease in 13 out of 14 patients. Similar high levels of p21 in sera were also found in 22 patients with benign hyperplasia of prostate. The p21 protein was not immunoreactive with known anti-ras antibodies such as Y13-259, 142-24E05 and anti-rap1. Partial amino acid analysis of this protein showed no complete homology to any known protein, but a partial homology to known bacterial proteins involved in DNA replication or transcription was observed. Monitoring of the novel p21 levels before and after treatment may be useful in follow-up of cancer patients, providing evidence of response to treatment.
从自身免疫复合物中分离出一种新型的21 kDa蛋白（p21），该复合物存在于14例泌尿生殖系统恶性肿瘤患者的血清中，并通过蛋白A-琼脂糖凝胶进行分离。分离出的复合物在15%聚丙烯酰胺-SDS迷你凝胶中进行分析。用考马斯亮蓝R染色后，用临床密度计扫描条带。癌症患者血清中p21的水平比正常个体高3倍。尝试将这些癌症患者血清中p21的连续水平与临床病程相关联。在4例患者中，观察到p21水平显著下降（57-75%），同时伴有对治疗的反应。在10例未观察到反应或肿瘤进展的患者中，有9例p21的相对丰度增加或保持不变。因此，在14例患者中的13例中，p21水平可指示疾病的进展或消退。在22例前列腺良性增生患者的血清中也发现了类似的高水平p21。p21蛋白与已知的抗ras抗体如Y13-259、142-24E05和抗rap1没有免疫反应性。对该蛋白的部分氨基酸分析显示，它与任何已知蛋白都没有完全同源性，但与参与DNA复制或转录的已知细菌蛋白有部分同源性。治疗前后监测新型p21水平可能对癌症患者的随访有用，可为治疗反应提供证据。
