Evaluate chemical carcinogens on Detroit 550 cells for in vitro transformation. Investigate the response of primary human fetal tissues to chemical carcinogens. Attempt to enhance the response of cells in culture with substances such as trypsin or methylmethanesulfonate (MMS), prior to treatment with chemical carcinogens. Determine the effects of the active intermediate of unsaturated polycyclic hydrocarbons, formed by treatment with the mixed function oxygenase system from rat liver microsomal fractions, on human cells in vitro. Continue to evaluate in vivo methods such as inoculation of immunosuppressed hamsters or intracerebral inoculation of mice to determine whether transformed cells are malignant.