Amplification of human int-2 in breast cancers and squamous carcinomas.

Murine int-2 is one of the genetic loci implicated in the induction of mouse breast cancers by murine mammary tumor virus. An homologous gene has recently been identified in the human genome (Casey et al., 1986). The human int-2 locus was found to be amplified 7- to 25-fold in 4 of 46 infiltrating ductal breast cancers and 30- to 60-fold in 2 of 8 squamous carcinomas of the head and neck region, but not in other cancers. All of the involved tumors had metastasized to regional lymphatics at the time of analysis and five exhibited clinically aggressive behavior.