The growth rate of the ovarian carcinoma tumors (A2780 Pgp− and A2780AD Pgp+) was slower (doubling time: 4 days) than that of the epidermoid carcinoma tumors (KB-3-1 Pgp− and KB-V-1 Pgp+; doubling time: 3 days). The gene discussed is PGP; the disease is squamous cell carcinoma.