Identification of rare variants in the hLIMD1 gene in breast cancer

The hLIMD1 gene is located at chromosome 3p21 and was identified as a putative tumor suppressor gene using an elimination test assay. Chromosome 3p21 loci are frequently deleted in a number of cancers, including breast. The 3p21.3 locus harbors a number of tumor suppressor candidates, including LIMD1, a member of the ZYXIN family of genes. LIMD1 directly interacts with RB and is thought to play a role in suppressing tumor growth. To investigate whether mutations in the LIMD1 gene could potentially be involved in breast cancer, we used single-stranded conformation polymorphism analysis on DNA from 235 breast cancers and 95 controls. We identified four novel coding region alterations, including two amino acid substitutions at positions 255 and 302. The two remaining novel variants were found at amino acid positions 246 and 647 and encoded silent alterations. The rare Ser255Arg variant was identified in only sporadic breast tumors (2/165 tumors). Some ZYXIN proteins are phosphorylated by serine/threonine kinases, and the Ser255Arg change is located in a region phosphorylated on serine residues. Together, the data suggest that this variant may warrant further characterization.