HCG secretion by human tumor lines was found to occur in the following pattern: Undifferentiated carcinomas, squamous cell carcinomas, and adenocarcinomas--beta HCG subunit; mucoepidermoid carcinomas--alpha HCG subunit; small cell carcinomas, large cell carcinomas, and mesotheliomas--no HCG. Secretion of beta HCG was highly correlated with activation of the Ki-ras or Ha-ras oncogene at codon 12. Activated myc and raf oncogenes in lung tumors and activated Ki-ras and Ha-ras in nonlung tumors were not correlated with HCG secretion. A method was developed for transfecting calcium-sensitive normal human bronchial cells (NHBE) with plasmid and genomic DNAs, using strontium ion to replace calcium. Transfection of the v-Ki-ras gene or an activated cellular-Ki minigene into NHBE did not result in HCG secretion. Infection with Kirsten sarcoma virus to increase the number of affected cells is in progress. Addition of alpha HCG, beta HCG, or alpha+beta HCG did not increase the growth rate of three human tumor cell lines secreting solely alpha or beta HCG subunits.
