Department of Surgical Oncology, Fox Chase Cancer Center, Philadelphia, PA 19111, USA.
Transl Oncol. 2010 Feb;3(1):33-42. doi: 10.1593/tlo.09187.
Barrett esophagus is an epithelial metaplasia that predisposes to adenocarcinoma. Better markers of cancer risk are urgently needed to identify those patients who are likely to benefit most from emerging methods of endoscopic ablation. Disease progression is associated with genomic DNA changes (segmental gains, losses, or loss of heterozygosity). Although these changes are not easily assayed directly, we hypothesized that the underlying DNA damage should activate a DNA damage response (DDR), detectable by immunohistochemical (IHC) assays of checkpoint proteins and the resulting replicative phase cell cycle delays. Surgical specimens and endoscopic biopsies (N = 28) were subjected to IHC for the cell cycle markers cyclin A and phosphorylated histone H3 (P-H3), the DDR markers gammaH2AX and phosphorylated ATM/ATR substrates (P-ATM/ATRsub), and the DNA damage-responsive tumor suppressors p16 and p53. Correlations were made with histologic diagnoses. The fractions of cells that stained for cyclin A, P-H3, and gammaH2AX increased in parallel in dysplastic tissue, consistent with checkpoint-mediated cell cycle delays. Foci of nuclear gammaH2AX and P-ATM/ATRsub were demonstrated by standard and confocal immunofluorescence. Staining for p16 was more prevalent in early-stage disease with lower staining for gammaH2AX and P-H3. Staining for p53 was moderately increased in some early-stage disease and strongly increased in some advanced disease, consistent with checkpoint-mediated induction and mutational inactivation of p53, respectively. We suggest that IHC for DDR-associated markers may help stratify risk of disease progression in Barrett.
巴雷特食管是一种上皮化生，易发生腺癌。迫切需要更好的癌症风险标志物来识别那些最有可能从新兴的内镜消融方法中获益的患者。疾病进展与基因组 DNA 变化（片段增益、缺失或杂合性丢失）有关。虽然这些变化不易直接检测，但我们假设潜在的 DNA 损伤应该激活 DNA 损伤反应（DDR），可通过细胞周期蛋白 A 和磷酸化组蛋白 H3（P-H3）、DDR 标志物γH2AX 和磷酸化 ATM/ATR 底物（P-ATM/ATRsub）以及 DNA 损伤反应性肿瘤抑制因子 p16 和 p53 的免疫组织化学（IHC）检测来检测。对 28 例手术标本和内镜活检进行了细胞周期标志物 cyclin A 和磷酸化组蛋白 H3（P-H3）、DDR 标志物γH2AX 和磷酸化 ATM/ATR 底物（P-ATM/ATRsub）以及 DNA 损伤反应性肿瘤抑制因子 p16 和 p53 的 IHC 检测，并与组织学诊断进行了相关性分析。在发育不良组织中，细胞周期蛋白 A、P-H3 和γH2AX 的染色细胞分数平行增加，这与检查点介导的细胞周期延迟一致。通过标准和共聚焦免疫荧光显示核γH2AX 和 P-ATM/ATRsub 的焦点。p16 的染色在疾病早期更为普遍，γH2AX 和 P-H3 的染色较低。p53 的染色在一些早期疾病中中度增加，在一些晚期疾病中强烈增加，分别与检查点介导的 p53 诱导和突变失活一致。我们认为，DDR 相关标志物的 IHC 可能有助于分层 Barrett 疾病进展的风险。
