Meenakshi A, Manoharan V
Department of Biochemical Oncology, Cancer Institute (W.I.A), Chennai, India.
Hum Antibodies. 1999;9(3):171-6.
Immunocytochemical localisation of mutant p53 in breast tumours serves as a potential prognostic molecular marker. In order to study the expression of p53 protein in breast cancer which constitutes the second most common malignancy in the South Indian female population, MAb CIBCVMC12 has been generated against human p53 protein isolated and purified from bacterial cell lysate of E.coli carrying the plasmid T 7-7 Hup53 grown in Luria broth to induce the expression of p53. The positive clones selected by ELISA were found to exhibit strong staining of nuclear p53 in both fresh and archival paraffin embedded breast tumour tissue sections. Commercial MAb D 07 against p53 was used as control. In immunoprecipitation, this MAb of IgG2b isotype was found to bind specifically to a protein of 53 kD. Immuno cyto chemical assay of normal, benign and malignant breast tissues of different histological types revealed that the majority of tumour cells were strong positive in the case of infiltrating ductal and lobular carcinomas, the staining being less intense for in situ carcinoma. The test for normal and benign tissues was negative. The staining patterns were comparable with those of control antibody. These results suggest that the MAb generated is specific to p53. The p53 protein expression was compared with the estrogen receptor (ER) status for 50 breast tumours which revealed that 38% of these were p53 positive and of these two were ER+. Among the p53 negative tumours, 48% were found to be ER+. A comparison of the p53 expression for 100 breast cancer patients indicated that 57% of the tumours were p53 negative and these patients had a longer overall 5 year survival rate and recurrent free interval which is statistically very significant. These results might suggest that p53 positive tumours are more aggressive biologically with poor prognosis.
乳腺肿瘤中突变型p53的免疫细胞化学定位可作为一种潜在的预后分子标志物。为了研究构成南印度女性人群中第二常见恶性肿瘤的乳腺癌中p53蛋白的表达情况，制备了单克隆抗体CIBCVMC12，该抗体针对从携带在Luria肉汤中生长以诱导p53表达的质粒T 7-7 Hup53的大肠杆菌细菌细胞裂解物中分离和纯化的人p53蛋白产生。通过酶联免疫吸附测定（ELISA）选择的阳性克隆在新鲜和存档石蜡包埋的乳腺肿瘤组织切片中均显示出核p53的强染色。使用针对p53的商业单克隆抗体D 07作为对照。在免疫沉淀中，发现这种IgG2b同种型的单克隆抗体与一种53 kD的蛋白质特异性结合。对不同组织学类型的正常、良性和恶性乳腺组织进行免疫细胞化学分析发现，在浸润性导管癌和小叶癌中，大多数肿瘤细胞呈强阳性，原位癌的染色强度较低。正常和良性组织检测为阴性。染色模式与对照抗体的相似。这些结果表明所产生的单克隆抗体对p53具有特异性。对50例乳腺肿瘤的p53蛋白表达与雌激素受体（ER）状态进行了比较，结果显示其中38%为p53阳性，其中2例为ER阳性。在p53阴性肿瘤中，48%被发现为ER阳性。对100例乳腺癌患者的p53表达进行比较表明，57%的肿瘤为p53阴性，这些患者的5年总生存率和无复发间隔期更长，这在统计学上具有非常显著的意义。这些结果可能表明p53阳性肿瘤在生物学上更具侵袭性，预后较差。
