Cui H, Horon I L, Ohlsson R, Hamilton S R, Feinberg A P
Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
Nat Med. 1998 Nov;4(11):1276-80. doi: 10.1038/3260.
Loss of imprinting (LOI) is an epigenetic alteration of some cancers involving loss of parental origin-specific expression of imprinted genes. We observed LOI of the insulin-like growth factor-II gene in twelve of twenty-seven informative colorectal cancer patients (44%), as well as in the matched normal colonic mucosa of the patients with LOI in their cancers, and in peripheral blood samples of four patients. Ten of eleven cancers (91%) with microsatellite instability showed LOI, compared with only two of sixteen tumors (12%) without microsatellite instability (P < 0.001). Control patients without cancer showed LOI in colonic mucosa of only two of sixteen cases (12%, P < 0.001) and two of fifteen blood samples (13%, P < 0.001). These data suggest that LOI in tumor and normal tissue identifies most colorectal cancer patients with microsatellite instability in their tumors, and that LO! may identify an important subset of the population with cancer or at risk of developing cancer.
印记丢失（LOI）是某些癌症的一种表观遗传改变，涉及印记基因亲本来源特异性表达的丧失。我们在27例信息充足的结直肠癌患者中的12例（44%）中观察到胰岛素样生长因子-II基因的LOI，在癌症中存在LOI的患者的匹配正常结肠黏膜以及4例患者的外周血样本中也观察到了该现象。11例微卫星不稳定的癌症中有10例（91%）显示LOI，而16例无微卫星不稳定的肿瘤中只有2例（12%）显示LOI（P<0.001）。无癌症的对照患者中，16例结肠黏膜中只有2例（12%，P<0.001）显示LOI，15例血液样本中有2例（13%，P<0.001）显示LOI。这些数据表明，肿瘤和正常组织中的LOI可识别出大多数肿瘤存在微卫星不稳定的结直肠癌患者，并且LOI可能识别出癌症患者或有患癌风险人群中的一个重要亚组。
