Elective vital staining of mouse tumors with labelled dyes

It was shown by vital staining in previous experiments (1) that carcinoma and sarcoma of mice could be selectively stained by certain dyes of the triphenyl methane sulphonic acid group. These findings were now confirmed in the present experiments by using labelled (125I) dyes of the same chemical group. In some mice the tumor tissue was the most radioactive, compared with other tissues. In other mice the tumor tissue was exceeded only by tissues which had a blood supply 5-time to 35-times higher. These were, in addition, excretory organs the excreta of which was highly radioactive (kidney and liver). The urine was 50-times more radioactive than the tumor and the bile was most probably not less. After deduction of the radioactivity of these two components, blood and excreta, from the radioactivity of the parenchyma tissue of the kidney and liver, the tumor tissue proved to be the most radioactive of all tissues tested. This indicates that tumor tissue retained the administered labelled dyes in higher concentration than all other tissues.