FREQUENT ALLELIC LOSS AT 7P14-15 ASSOCIATED WITH AGGRESSIVE HISTOLOGIC TYPES OF BREAST-CANCER

We examined 142 primary human breast cancers to determine their patter ns of loss of heterozygosity (LOH) at 19 microsatellite markers over t he entire length of chromosome 7, Allelic loss at one or more loci on the short arm of chromosome 7 was observed in 37 of the tumors (26%), We found a new target region of allelic loss on 7p between D7S1802 and D7S817 at 7p14-15, LOH on 7p was found more frequently in tumors of t he invasive solid tubular and scirrhous type (31 of 87; 36%) than in o ther less aggressive types (2 of 27; 7%) (P=0.0047), The results sugge st that inactivation of putative tumor suppressor gene(s) located at 7 p14-15 may play a role in the development and/or progression of primar y breast cancers, particularly those of the invasive solid tubular and scirrhous type. Allelic loss was also found in 56 of 142 tumors on th e long arm, and a commonly deleted region was defined between D7S522 a nd D7S1801 at 7q31.