FOR CHEMOTHERAPY of cancer, much work has been done on antimetabolites for deoxyribonucleic acid (DNA) but little on attack at the protein associated with DNA. Yet, by analogy with viruses, such an attack on protein coat of nucleic acid may be fruitful, since viral nucleic acid stripped of protein coat can drop in activity to 1/1000 of that of native nucleic acid with intact protein coat. Deliberate attack on the protein coat of DNA is therefore being studied for coordinated surgicalchemical therapy of human cancer.
The protein associated with DNA stains more intensely for protein-sulfhydryl groups than does any other part of the dividing cell. All steps of the mitotic cycle can be delineated by histological stains which react only with sulfhydryl groups. Also, the potent sulfhydryl inhibitor oxophenarsine rapidly causes profound damage to the mitotic apparatus, Roosa and De Lamater1 found in studies on mouse tumors.