The LASP1 gene was initially identified together with three other genes from a cDNA library of metastatic axillary lymph nodes (MLN) from human breast cancer and therefore called MLN50. All four genes were mapped to chromosomal region 17q11-q21.3, a region known to contain the c-erbB-2 and the BRCA1 oncogene and to be altered in 20–30% of all breast cancers [1,2]. This evidence concerns the gene BRCA1 and breast cancer.