Vanni R, Schoenmakers E F, Andria M
Center for Human Genetics, University of Leuven, Belgium.
Cancer Genet Cytogenet. 1999 Sep;113(2):183-7. doi: 10.1016/s0165-4608(99)00025-4.
Deletions of the long arm of chromosome 7 constitute one of the most common clonal chromosomal changes associated with uterine leiomyoma cells. Recently, the molecular cytogenetic refinement of 7q deletions in two myoma-derived cell lines, with the use of a panel of 39 ordered 7q DNA probes corresponding to 87 genetic markers, showed results in line with those obtained by loss of heterozygosity (LOH) analysis. Referring to this panel, we extended fluorescence in situ hybridization (FISH) analysis on primary cytogenetic preparations from three myomas with del(7q), thereby avoiding cell passages. This was fundamental in the maintenance of cells with del(7q) in the two cases showing mosaicism (i.e., the presence of an extra normal clone), which are prone to lose the abnormal clone in the very early passages. The data obtained, together with previously published findings on the two leiomyoma-derived cell lines, indicated a commonly deleted region of 11 cM. If the fact that the presence of normal cells may interfere with LOH analysis is taken into account, the FISH approach seems to be a reliable complementing tool for refining the deletion and analyzing the smallest overlapping region in cases with both normal and del(7q) cells.
7号染色体长臂缺失是与子宫平滑肌瘤细胞相关的最常见的克隆性染色体改变之一。最近，利用一组对应于87个遗传标记的39个有序7q DNA探针，对两个肌瘤来源的细胞系中的7q缺失进行分子细胞遗传学精细定位，结果与通过杂合性缺失（LOH）分析获得的结果一致。参照该探针组，我们对来自三个具有del(7q)的肌瘤的原代细胞遗传学标本进行了荧光原位杂交（FISH）分析，从而避免了细胞传代。在两例显示嵌合体（即存在额外的正常克隆）的病例中，这对于维持具有del(7q)的细胞至关重要，因为这些细胞在非常早期的传代中容易丢失异常克隆。获得的数据，连同先前发表的关于两个平滑肌瘤来源细胞系的研究结果，表明存在一个11 cM的常见缺失区域。如果考虑到正常细胞的存在可能干扰LOH分析这一事实，FISH方法似乎是一种可靠的补充工具，可用于在同时存在正常细胞和del(7q)细胞的情况下，精细定位缺失区域并分析最小重叠区域。
