The importance of tamoxifen to a cisplatin-containing regimen in the treatment of metastatic melanoma.

The combination of dacarbazine (DTIC, 220 mg/m2) and cisplatin (DDP, 25 mg/m2) IV daily for 3 days every 3 weeks, carmustine (BCNU, 150 mg/m2) IV every 6 weeks, and tamoxifen (TAM, 10 mg orally twice daily) produced a 50% objective response rate in patients with metastatic melanoma. Associated with this treatment, there was a high incidence of deep venous thrombosis (DVT) and pulmonary embolism (PE). In an effort to reduce this toxicity, this regimen minus TAM was studied, and the results are reported. Twenty of twenty patients are evaluable for response and toxicity. There was one complete response (CR) lasting 5+ months and one partial response (PR) lasting 4+ months for an overall response rate of 10% (95% confidence limits, 1.23% to 31.70%). Two patients exhibited a mixed response and three patients developed disease stabilization lasting 4 to 10 months. Toxicity was similar to the original study except that no patients developed DVT or PE. This statistically significant (Fisher's exact test [two-tail] P = 0.008) decrease in the response rate by comparison with that achieved with the TAM-containing regimen may signal an essential role of TAM in this regimen. TAM may be acting in synergy with cisplatin through its calcium channel-blocking properties. TAM should be included as described in the initial reports, and the patients should be carefully observed for vascular complications.

Cultured human umbilical vein endothelial cells contain a membrane glycoprotein immunologically related to platelet glycoprotein Ib.

Using a platelet glycoprotein Ib (GpIb)-specific monoclonal antibody, AP-1, we have studied cultured human umbilical vein endothelial cells (HUVEC) for the presence of GpIb. Radiolabeled AP-1 bound specifically and saturably to HUVEC in suspension and detected a single class of binding sites (100,000/cell). When Triton X-100 extracts of HUVEC were chromatographed on wheat germ agglutinin (WGA)-Sepharose, radioiodinated, precipitated with AP-1, and subjected to reduced sodium dodecyl sulfate-polyacrylamide electrophoresis (SDS-PAGE), major radioactive bands of 228,000, 145,000, and 130,000 were seen. The latter two bands correspond to the 156,000 and 140,000 bands, representing GpIb alpha and glycocalicin, respectively, which are seen when platelets are subjected to the same procedure. The 228,000 band corresponds to a band previously noted in immunoprecipitates of platelet GpIb but not fully explained. When HUVEC were grown in the presence of 35S-methionine, extracted with Triton X-100, chromatographed on WGA-Sepharose, immunoprecipitated with AP-1, and subjected to reduced SDS-PAGE, radioactive bands of 210,000, 156,000, and 90,000 were seen. We conclude that cultured HUVEC synthesize and express on their surface a glycoprotein immunologically related to platelet GpIb.