Kilias D, Macrae F A, Sharpe K, Young G P
Department of Medicine, University of Melbourne, Victoria, Australia.
Cancer Epidemiol Biomarkers Prev. 1997 Oct;6(10):819-24.
Rectal epithelial cell kinetics are used as intermediate markers for colorectal cancer and relate to risk. In this study, measures of proliferation using direct immunohistochemistry for proliferating cell nuclear antigen (PCNA) were compared to in vitro labeling by bromodeoxyuridine (BrdUrd) and incubated biopsies that were later stained for PCNA (PCNA-I) in human rectal biopsies. The study group consisted of 20 sets of biopsies from 12 subjects participating in an intervention trial. Fresh nonincubated biopsies were fixed in methacarn and stained immunohistochemically for PCNA (clone 19A2). In parallel biopsies, BrdUrd was incorporated into the DNA of S-phase cells during a 2-h incubation at 37 degrees C under hyperbaric conditions and localized by immunohistochemistry. Additionally, biopsies were incubated under hyperbaric conditions for 2 h at 37 degrees C, fixed in methacarn, and stained for PCNA (PCNA-I). There was a highly significant difference in the labeling index between the three methods (P < 0.01), but there was no significant difference between subjects (P = 0.439). The mean labeling index was 2.3 +/- 0.1% for PCNA, 2.9 +/- 0.1% for PCNA-I, and 4.1 +/- 0.1% for BrdUrd. The proportion of labeled cells in the top two-fifths was significantly higher (P = 0.01) for BrdUrd (5.5 +/- 0.8%) and PCNA-I (6.4 +/- 1.1%) compared to PCNA (3.1 +/- 0.6%), and a significant difference was seen between subjects (P = 0.038). PCNA-I and BrdUrd methods had similar crypt heights with 73.5 +/- 1.8 and 71.2 +/- 1.3 cells/crypt column, respectively, but were significantly shorter (P < 0.001) than PCNA with 83.4 +/- 1.5 cells/crypt column, indicating a loss of cells during organ culture. The simplicity of the PCNA technique, which avoids potential perturbations occurring during organ culture, has considerable appeal as a marker for colorectal cancer risk, but additional studies are needed to correlate PCNA with neoplastic risk.
直肠上皮细胞动力学被用作结直肠癌的中间标志物并与风险相关。在本研究中，将使用增殖细胞核抗原（PCNA）直接免疫组织化学法进行增殖测量与溴脱氧尿苷（BrdUrd）体外标记以及人直肠活检组织中后续进行PCNA染色（PCNA - I）的孵育活检组织进行了比较。研究组由参与一项干预试验的12名受试者的20组活检组织组成。新鲜未孵育的活检组织用甲醇 - 冰醋酸固定并进行PCNA免疫组织化学染色（克隆19A2）。在平行活检组织中，在37℃高压条件下孵育2小时期间，BrdUrd掺入S期细胞的DNA中，并通过免疫组织化学进行定位。此外，活检组织在37℃高压条件下孵育2小时，用甲醇 - 冰醋酸固定，并进行PCNA染色（PCNA - I）。三种方法之间的标记指数存在高度显著差异（P < 0.01），但受试者之间无显著差异（P = 0.439）。PCNA的平均标记指数为2.3±0.1%，PCNA - I为2.9±0.1%，BrdUrd为4.1±0.1%。与PCNA（3.1±0.6%）相比，BrdUrd（5.5±0.8%）和PCNA - I（6.4±1.1%）在前五分之二的标记细胞比例显著更高（P = 0.01），且受试者之间存在显著差异（P = 0.038）。PCNA - I和BrdUrd方法的隐窝高度相似，分别为73.5±1.8和71.2±1.3个细胞/隐窝柱，但明显短于PCNA的83.4±1.5个细胞/隐窝柱（P < 0.001），表明在器官培养过程中细胞有丢失。PCNA技术的简便性避免了器官培养过程中可能出现的干扰，作为结直肠癌风险标志物具有相当大的吸引力，但需要进一步研究将PCNA与肿瘤风险相关联。
