Jaïs P, Kapel N, Chosidow D, Rupaire N, Rougier P, Lasser P, Mignon M, Lewin M J, Gobert J G
INSERM Unité 10, Hôpital Bichat, Paris.
Gastroenterol Clin Biol. 1997;21(10):754-9.
Mutations of TP53, a tumor suppressor gene, are found in 60% to 70% of colorectal cancers. These mutations usually induce an overexpression caused by modification of the p53 protein conformation. The aim of this study was to investigate whether stool specimens of patients with colorectal cancer contain increased amounts of p53 protein.
p53 protein was measured using a sandwich enzyme immunoassay in the stool specimens of 52 patients: 25 with colorectal cancer, 4 with colorectal adenomas and 23 apparently free of gastrointestinal disease. Results were expressed as pg/mg of total protein. The presence of fecal occult-blood was searched using Hemoccult II and Hemolex (an immunochemical assay for human hemoglobin).
Median concentrations of stool p53 protein were 16.6 pg/mg (range: 0-591 pg/mg) in patients with colorectal cancers, 39.1 pg/mg (range: 5-72 pg/mg) in patients with adenomas and 5.9 pg/mg (range: 0-65 pg/mg) in control subjects. Resection of colorectal cancers caused a marked decrease of stool p53 protein concentrations. When the cut-off value for stool p53 protein was set at 60 pg/mg of fecal protein (concentrations over the 95th percentile), the positivity of the assay was independent of tumor size and Astler-Coller stage, but weakly associated with rectal location of cancer. The sensitivity of stool p53 protein for colorectal cancer was 44%, and the specificity was 96%. In contrast, the sensitivity of Hemoccult II and Hemolex tests was 48% and 44%, whereas their specificity was 91% and 96%, respectively.
The detection of p53 protein is achievable in stool, but this assay is not more efficient than fecal occult blood tests for detection of colorectal cancer.
肿瘤抑制基因TP53的突变见于60%至70%的结直肠癌中。这些突变通常会因p53蛋白构象改变而导致其过度表达。本研究的目的是调查结直肠癌患者的粪便标本中p53蛋白含量是否增加。
采用夹心酶免疫测定法检测52例患者粪便标本中的p53蛋白：25例结直肠癌患者、4例结直肠腺瘤患者和23例明显无胃肠道疾病的患者。结果以每毫克总蛋白中的皮克数表示。使用Hemoccult II和Hemolex（一种人血红蛋白免疫化学测定法）检测粪便潜血。
结直肠癌患者粪便p53蛋白的中位浓度为16.6 pg/mg（范围：0 - 591 pg/mg），腺瘤患者为39.1 pg/mg（范围：5 - 72 pg/mg），对照受试者为5.9 pg/mg（范围：0 - 65 pg/mg）。结直肠癌切除术后粪便p53蛋白浓度显著降低。当粪便p53蛋白的临界值设定为每毫克粪便蛋白60 pg（浓度超过第95百分位数）时，该检测的阳性结果与肿瘤大小和阿斯特勒-科勒分期无关，但与癌症的直肠部位弱相关。粪便p53蛋白检测结直肠癌的敏感性为44%，特异性为96%。相比之下，Hemoccult II和Hemolex检测的敏感性分别为48%和44%，而其特异性分别为91%和96%。
粪便中可检测到p53蛋白，但该检测在结直肠癌检测方面并不比粪便潜血检测更有效。
