A HAMARTOMA OF THE BREAST WITH AN ABERRATION OF 12Q MAPPED TO THE MARREGION BY FLUORESCENCE IN-SITU HYBRIDIZATION

Cytogenetic studies of a breast adenolipoma (hamartoma) of a 58-year-o ld patient revealed a karyotype 46,XX,add(4)(?),add(6)(q?),der(7)t(7;1 2)(q11.1 or q11.2;q11 or q12),der(12). To our knowledge, this is the s econd report of an aberration involving 12q12-15 in a hamartoma of the breast. By FISH studies, we found this chromosome 12 translocation br eakpoint to be mapping within the MAR (Multiple Aberration Region). MA R is known to be a major cluster region of chromosome 12 breakpoints o f benign solid tumors such as uterine leiomyoma, lipoma, and pleomorph ic salivary gland adenomas, therefore raising the possibility that the same gene is involved in hamartoma of the breast as in these three be nign solid tumors.