Transferrin receptors on proliferating and malignant cells are well documented. Faulk et al. demonstrated
transferrin receptors in
breast carcinoma by immunofluorescence. Malignant cells requiring more
iron modulate a
transferrin receptor and the
iron transporting
protein transferrin delivers
iron to the cell. We have developed a physiologically active
platinum transferrin complex that has been tested on several cell lines in culture, a
tumor model in the Fischer rat, and five human patients with advanced
breast carcinoma. The complex slowed the rate of growth of feline
lymphoma cells to one-half that of controls and killed human HeLa cell cultures in 7 days. Growth of the rat
tumor was slightly impaired, but treated rats never got systemic disease and controls died. Two patients had dramatic responses to treatment. One had systemic disease and the other advanced locoregional disease. Both patients were on
Tamoxifen, as receptors were positive for
estrogen. Disease was progressing in the former with little improvement in the latter.
After treatment both had a marked response. We postulate that
MPTC-63 may work synergistically with
Tamoxifen and be an effective nontoxic
antitumor agent. More studies are indicated.