Amplification of the human putative oncogene INT1 in primary retinoblastoma tumors

We report the amplification of the putative oncogene INT1 in two of four retinoblastomas. In one case, the INT1 signal was amplified 10 to 15-fold, in the other 100-fold. In both cases there were signs of increased tumor aggressiveness with invasion of the choroid and development of metastases. The two cases without INT1 amplification had neither metastases nor locally invasive growth. Our findings indicate that INT1 amplification may be a feature of increased malignant potential in retinoblastomas.