Nishimura Takafumi, Nishida Naoshi, Itoh Teruaki, Kuno Masato, Minata Mutsuko, Komeda Toshiki, Fukuda Yoshihiro, Ikai Iwao, Yamaoka Yoshio, Nakao Kazuwa
Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto, Japan.
Genes Chromosomes Cancer. 2002 Dec;35(4):329-39. doi: 10.1002/gcc.10126.
Allelic imbalance (AI), which represents certain chromosomal gains or losses, has been described in human hepatocellular carcinoma (HCC), but the impact of AI on the early stage of hepatocarcinogenesis has not been fully clarified. Moreover, no previous allelotype studies have identified the difference in chromosomal gain and loss that results in AI. To resolve these problems, we examined 18 well-differentiated HCCs with comprehensive allelotyping by using 400 microsatellite markers with semiquantitative assessment of chromosomal gain or loss. To detect allelic gain effectively, the cutoff value of the allelic imbalance index was set at 0.70. Each allele showing imbalance was subjected to multiplex PCR with use of a retained allele as an internal control to determine whether the imbalance was the result of chromosomal gain or loss. High frequencies of chromosomal gains were detected at 1q (D1S196-D1S2785, 56%), 5q (D5S647-D5S2027, 44%), 6p (6pter-D6S309, 33%), 7 (7pter-D7S657, 22%), and 8q (D8S514-qter, 44%), whereas chromosomal losses were frequently observed at 1p (1pter-D1S234, 22%), 8p (8pter-D8S549, 44%), and 17p (17pter-D17S921, 28%). The extent of overall chromosomal aberration was closely related to the maximum tumor diameter (P = 0.002) and the presence of hepatitis B surface antigen (P = 0.03). Recurrent chromosomal losses at 1p and 8p and gains at 1q and 8q, even in HCCs with a minimal extent of aberrant chromosomes, indicate that these alterations were critical in the early stage of hepatocarcinogenesis. On the other hand, deletions of 13q and 16q were infrequent and were seen only in the most aberrant cases, which suggested that these were late events.
等位基因失衡（AI）代表特定的染色体增加或缺失，已在人类肝细胞癌（HCC）中被描述，但AI对肝癌发生早期阶段的影响尚未完全阐明。此外，以前的等位基因分型研究均未确定导致AI的染色体增加和缺失的差异。为了解决这些问题，我们通过使用400个微卫星标记对18例高分化HCC进行了全面的等位基因分型，并对染色体增加或缺失进行了半定量评估。为了有效检测等位基因增加，将等位基因失衡指数的临界值设定为0.70。对每个显示失衡的等位基因进行多重PCR，以保留的等位基因为内部对照，以确定失衡是染色体增加还是缺失的结果。在1q（D1S196 - D1S2785，56%）、5q（D5S647 - D5S2027，44%）、6p（6pter - D6S309，33%）、7（7pter - D7S657，22%）和8q（D8S514 - qter，44%）检测到高频率的染色体增加，而在1p（1pter - D1S234，22%）、8p（8pter - D8S549，44%）和17p（17pter - D17S921，28%）经常观察到染色体缺失。总体染色体畸变程度与最大肿瘤直径密切相关（P = 0.002），与乙肝表面抗原的存在也密切相关（P = 0.03）。即使在染色体畸变程度最小的HCC中，1p和8p的反复染色体缺失以及1q和8q的增加，表明这些改变在肝癌发生的早期阶段至关重要。另一方面，13q和16q的缺失很少见，仅在最畸变的病例中出现，这表明这些是晚期事件。
