Amplification of the int-2 gene in primary human breast tumors.

Proviral activation of the int-2 gene is a frequent occurrence in mammary carcinomas induced by mouse mammary tumor virus (MMTV). Here, we have examined the human homolog of int-2 in 110 primary breast cancer DNAs. The locus was amplified 2- to 15-fold in 18 of the tumor DNA samples. Amplification of int-2 has a highly significant association (P less than 2 X 10(-6] with tumors from patients who subsequently developed a local recurrence of the disease or a distal metastasis.