The Chromosome Location of the Human Homolog of the Mouse Mammary Tumor-Associated GeneINT6and Its Status in Human Breast Carcinomas

TheINT6gene is a common integration site for the mouse mammary tumor virus in mouse mammary tumors. We have determined that the human homolog ofINT6is located on chromosome region 8q22–q23. A processedINT6pseudogene is located on chromosome 6q.INT6is composed of 13 exons that span 45 kb of genomic DNA. The deduced amino acid sequence of the gene product is identical to the mouse protein and contains three potential translation start signals. We have examined 100 primary breast carcinoma DNAs for evidence of genetic alteration affectingINT6.Loss of heterozyosity (LOH) was detected in 11 of 39 (28%) of the tumor samples informative for a polymorphic sequence in intron 7 ofINT6.Since single-strand conformation and hybrid mismatch analysis of the remaining allele in these tumor DNAs failed to detect any mutations, we conclude that the target gene for LOH must be closely linked toINT6.