Vagner-Capodano A M, Zattara-Cannoni H, Gambarelli D, Gentet J C, Genitori L, Lena G, Graziani N, Raybaud C, Choux M, Grisoli F
Department of Pediatric Oncology, Hôpital Timone, Marseille, France.
Cancer Genet Cytogenet. 1994 Nov;78(1):1-6. doi: 10.1016/0165-4608(94)90037-x.
Medulloblastomas are the most frequent primitive neurectodermal tumors in children. An isochromosome for the long arm of 17, i(17q), is found in 30% of medulloblastomas. For some authors, this abnormality is observed in cases with a shorter survival time. In our cytogenetic studies of 30 medulloblastomas, we observed i(17q) in only three cases, a monosomy 17 in two cases, a monosomy 22 in four cases, nonspecific numerical or structural abnormalities in five cases, and normal karyotypes in 12 cases. We compared the results of karyotypic analysis after culture and FISH with a chromosome 17 alpha satellite DNA probe on interphase nuclei in five cases of medulloblastoma. In one case, i(17q) was only observed in four cells in karyotypic analysis, in three cases a normal karyotype was found, and in one case karyotypic analysis was impossible. In all of these cases, i(17q) was observed in a great number of nuclei by FISH on interphase nuclei. Our study shows that the FISH on interphase nuclei permitted us to observe i(17q) in the cases where it was not or could not be completely detected by karyotypic analysis. The association of these two techniques is required to detect i(17q), an abnormality whose prognosis value in medulloblastomas is now recognized.
髓母细胞瘤是儿童中最常见的原始神经外胚层肿瘤。17号染色体长臂等臂染色体，即i(17q)，在30%的髓母细胞瘤中被发现。对于一些作者来说，这种异常在生存时间较短的病例中被观察到。在我们对30例髓母细胞瘤的细胞遗传学研究中，我们仅在3例中观察到i(17q)，2例中观察到17号染色体单体，4例中观察到22号染色体单体，5例中观察到非特异性的数目或结构异常，12例核型正常。我们比较了5例髓母细胞瘤培养后核型分析的结果以及用17号染色体α卫星DNA探针在间期核上进行荧光原位杂交（FISH）的结果。在1例中，核型分析仅在4个细胞中观察到i(17q)，3例中发现核型正常，1例无法进行核型分析。在所有这些病例中，通过间期核FISH在大量核中观察到了i(17q)。我们的研究表明，间期核FISH使我们能够在核型分析未检测到或无法完全检测到i(17q)的病例中观察到它。检测i(17q)需要这两种技术联合使用，i(17q)这种异常在髓母细胞瘤中的预后价值现已得到认可。
