These observations indicate that OCT3 protein is selectively expressed in human breast cancer cells, and its expression may be implicated in mammary gland tumorigenesis via up-regulating FGF-4 expression.
To elucidate the role of hst in pituitary tumorigenesis we treated primary rat pituitary and pituitary tumor cell cultures with recombinant FGF-4 and also stably transfected pituitary cell lines with full-length human hst cDNA.
Although hst-1 and int-2 are usually not expressed despite amplification, elevated transcription of the cyclin D gene is accompanied by its amplification, suggesting a role of a G1 cyclin in oesophageal carcinogenesis.
These results suggest that amplification of chromosomal locus of the hst-1 and int-2 genes might participate in carcinogenesis, in progression, and particularly in metastasis of esophageal carcinomas.