HMGIY is the target of 6p21.3 rearrangements in various benign mesenchymal tumors.

Specific chromosomal abnormalities of chromosomal region 6p21.3 have been described in subsets of many benign mesenchymal tumors. In the presented study, we investigated a series of 36 such cases by FISH, and Southern blot analyses for HMGIY rearrangements.

Genomic changes in endometrial polyps associated with tamoxifen show no evidence for its action as an external carcinogen.

Eighty-eight endometrial specimens from 36 postmenopausal breast cancer patients treated with tamoxifen were investigated cytogenetically and molecularly using fluorescence in situ hybridization with appropriate probes for the HMGIC and HMGIY genes. Twenty control specimens, 10 endometrial polyps, and 10 endometrial biopsy specimens were investigated in the same way. Of the 88 specimens, 44 were from endometrial polyps; 3 were from endocervical polyps; 7 were from cystic endometrium; 30 were from normal or atrophic endometrium, normal endocervix, or myometrium; and 4 were from endometrial carcinomas.

Amplification and expression of the HMGIC gene in a benign endometrial polyp.

In a totally benign endometrial polyp, double minute chromosomes were shown to contain an amplified and apparently nonrearranged HMGIC gene, expressed in the tumor cells, suggesting amplification of HMGIC through double minute chromosome formation as another hitherto unreported mechanism associated with the development of some mesenchymal tumors.

Cloning and molecular characterization of part of a new gene fused to HMGIC in mesenchymal tumors.

Aberrations of the HMGIC gene, encoding an architectural transcription factor and located in the chromosomal region 12q15, are very frequent among benign mesenchymal tumors, such as lipomas, uterine leiomyomas, or pulmonary chondroid hamartomas. These HMGIC aberrations are caused by characteristic structural chromosomal aberrations, either visible by conventional cytogenetics or as cryptic abnormalities. Some of these aberrations of chromosome 12 are not specific for particular tumor entities but can occur in a variety of tumors with HMGIC abnormalities.

Hamartoma of the breast with involvement of 6p21 and rearrangement of HMGIY.

The first description of involvement of 6p21 and rearrangement of HMGIY in a hamartoma of the breast is in keeping with the emerging role of HMG genes in benign mesenchymal tumors.