Detection of Numerical Alterations of Chromosomes 3, 7, 17 and X in Low-grade Intracystic Papillary Tumors of the Breast by Multi-color Fluorescence In Situ Hybridization.

Intracystic papillary tumors of the breast comprise intraductal papillomas and low-grade papillary carcinomas. To determine chromosomal alterations that may be characteristic of these tumors, chromosomes 3, 7, 17 and X were examined in 10 intraductal papillomas and 14 low-grade papillary carcinomas using multicolor fluorescent in situ hybridization. In papillry carcinomas, numerical/structural alterations in chromosome 17 and the accumulation of numerical alterations in chromosomes 3, 7 and X were detected in 21%(3/14) and 15%(2/13) of the cases, respectively. These changes were not detected in papillomas. Loss of chromosome 17p was detected in only one of the 11 DNA-diploid carcinomas, whereas alterations in all four chromosomes were present in a case of DNA-aneuploid carcinoma. Numerical alterations of chromosomes 3, 7, 17 and X do not appear to be involved in the development of low-grade papillary carcinomas with DNA diploidy, but rather accumulate during the formation of DNA-aneuploid carcinoma cells in association with other chromosome alterations.