LOSS OF CHROMOSOME 8P SEQUENCES IN HUMAN BREAST-CARCINOMA CELL-LINES

Cytogenetic and molecular analyses of human breast cancer cells have i dentified consistent losses of specific chromosomal regions in these t umors, suggesting that such regions harbor tumor suppresser genes whos e homozygous loss or inactivation directly contributes to tumorigenesi s. To date, deletions of chromosome 8 sequences have been described in frequently and only in low percentages of breast carcinomas. We report the identification of a new DNA marker on chromosome 8p that is delet ed in 6 (75%) of 8 breast carcinoma cell lines and in 1 primary breast carcinoma examined. No deletion of this marker was detected in any no rmal or nonbreast carcinoma cell lines analyzed. Southern blot and flu orescence in situ hybridization studies indicate that this clone maps to chromosome 8 between bands p12 and p21. These observations suggest that a new gene, whose loss or inactivation may foster breast carcinom a tumorigenesis, may reside in this chromosome 8p region.