Abstract
In cultures of primary rat kidney cells numerous foci of transformed cells were observed 14 to 18 days after inoculation with adenovirus type 12. These foci were readily identified in medium containing 1.8 mM calcium. Serial lines of transformed cells could only be established in medium with a low calcium concentration. Transformation was apparent because of the altered morphology, loss of contact inhibition, oncogenicity and the presence of virus specific tumour antigen. No infectious virus could be recovered from the transformed cell lines. The induced tumour in rats had the appearance of a poorly differentiated carcinoma with occasional formation of tubules.