Identification of transforming genes as hst in DNA samples from two human hepatocellular carcinomas

In a DNA-mediated transfection assay using NIH3T3 cells, the DNAs from two out of twelve human hepatocellular carcinomas gave transformants. The transforming gene was identified as hst, which was originally found in DNAs from stomach cancers and a noncancerous portion of stomach mucosa, the putative product being a growth factor. Transcripts were not detected in the original HCC 1 and HCC2 upon Northern blot analysis. The possible mechanisms involved in the hst gene activation are discussed.