Human breast cancer cells, MB-468 (■–■), MB-453 (◆–◆) and MB-231 (▲–▲) or normal human cells, MCF 10A (•–•), MCF 12F (X–X) and HS 68 (*–*) were infected with 300 moi of AdCMV E1A 1-80 C+ and cell viability measured as described in the Materials and Methods. Results are the average of three or more experiments except for HS 68, which is the average of two experiments.