Nonrandom cell-cycle timing of a somatic chromosomal translocation: The t(X;17) of alveolar soft-part sarcoma occurs in G2
✍ Scribed by Hsuan-Ying Huang; Man Yee Lui; Marc Ladanyi
- Book ID
- 102843068
- Publisher
- John Wiley and Sons
- Year
- 2005
- Tongue
- English
- Weight
- 530 KB
- Volume
- 44
- Category
- Article
- ISSN
- 1045-2257
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✦ Synopsis
Abstract
The cell‐cycle timing of somatic chromosomal translocations in cancer remains poorly understood but may be relevant to their etiology and the mechanism of their formation. Alveolar soft‐part sarcoma (ASPS) is a rare malignant soft‐tissue tumor of uncertain lineage that provides an opportunity to address this question. The great majority of ASPSs have relatively simple near‐diploid karyotypes characterized by an unbalanced der(17)t(X;17)(p11.2;q25), resulting in nonreciprocal fusion of TFE3 with ASPSCR1 (a.k.a. ASPL), with consequent net gain of Xp11.2→pter and loss of 17q25→qter. The presence of a normal X along with the der(17)t(X;17) in ASPSs that occur in men has been well described in previous cytogenetic reports and is most readily explained by a translocation in the G2 phase of the cell cycle. To establish whether formation in G2 is a general feature of the t(X;17), we examined polymorphic loci in Xp11.2→qter in ASPS from 9 women, including 7 with an unbalanced t(X;17). Our analysis showed that all 7 displayed retention of heterozygosity at all informative markers on Xp11.2→qter, supporting preferential formation of the t(X;17) in the G2 phase of the cell cycle. Given that the two derivative chromosomes of a translocation in G2 would be expected to segregate together half the time, the predominance of an unbalanced der(17)t(X;17) also raises the possibility of a selective advantage in ASPS cells for gain of Xp11.2→pter or loss of 17q25.3→qter or retention of an active copy of TFE3. © 2005 Wiley‐Liss, Inc.