HIGH-LEVELS OF ALLELE LOSS AT THE FHIT AND ATM GENES IN NON-COMEDO DUCTAL CARCINOMA IN-SITU AND GRADE-I TUBULAR INVASIVE BREAST CANCERS

Fifty-four grade I tubular breast cancers and nine non-comedo ductal c arcinoma in situ samples have been analyzed for lass of heterozygosity using a series of microsatellite markers. Markers mapping to regions of the genome for which loss of heterozygosity has been documented pre viously in higher-grade breast cancers were selected for this analysis . Even within this group of goad prognostic early breast cancers, gene tic events are very common. The highest levels of loss were observed f or D3S1300, which maps within an intron of the recently identified FRI T gene. High levels of loss mere also observed within the ATM gene. Th ese findings indicate that allele loss at FHIT and ATM may be an impor tant early event in the development of sporadic breast cancer.