Since June 1978, 57 patients with primary osteogenic sarcoma of an extremity were treated with high-dose methotrexate (HDMTX) and citrovorum factor rescue (CFR), Adriamycin, and the combination of bleomycin, cyclophosphamide and dactinomycin (BCD) given for 4-16 weeks prior to definitive surgery. Histologic examination of the resected primary tumor determined the effect of preoperative chemotherapy with many primary tumors showing greater than 90% tumor necrosis attributable to preoperative chemotherapy. A l l patients having this favorable effect of chemotherapy on the primary tumor were continued on the same chemotherapy regimen postoperatively (regimen B). However, in those patients not having a good effect of preoperative chemotherapy on the primary tumor, H D M T X with CFR was subsequently deleted from their postoperative chemotherapy and they were placed on a regimen containing cisplatinum at the dose of 120mg/M2 with mannitol diuresis combined with Adriamycin i n addition to BCD (regimen A). In the current study, 35 of the 57 patients did not demonstrate a good effect of chemotherapy on the primary tumor and were assigned to regimen A postoperatively. Of these 35 patients, 32 (91%)) have remained continuously free of recurrent or metastatic disease from 6-34 months following the start of therapy. Among the 22 remaining patients having a good histologic response and treated with regimen B postoperatively, there has been only one relapse in a patient who had a local recurrence in the area of an inadequately resected primary tumor three months after the cessation of chemotherapy. Thus, 53 of 57 patients (93%) are continuously with no evidence of recurrent or metastatic disease from 6-35 months (median, 20 months) from the start of treatment. This study demonstrates the value of thorough histologic examination in predicting survival i n responding patients and i n helping identify patients whose disease-free survival rate can be substantially increased if they are given alternative postoperative adjuvant chemotherapy after failing to have a good response to preoperative chemotherapy. This individualized chemotherapeutic strategy has yielded the highest disease free survival raw reported to date for osteogenic sarcoma.

The kinetics and distribution of methotrexate in intraventricular and intrathecal cerebrospinal-fluid spaces were studied in patients with meningeal leukemia and meningeal carcinomatosis after drug administration by intravenous infusion, indwelling intraventricular subcutaneous reservoir (Ommaya), or standard lumbar puncture. Negligible ventricular concentrations followed a single intravenous dose. During an intravenous infusion (500 mg per square meter for 24 hours) the ventricular cerebrospinal-fluid concentration rose to 6 times 10-minus 7 M. Methotrexate administered by Ommaya reservoir, at a dose of 6.25 mg per square meter, rapidly distributed in the subarachnoid space; the peak ventricular concentration of 2 times 10-minus 4 M declined exponentially over 48 hours. Lumbar cerebrospinal-fluid concentration reached a maximum of 5 times 10-minus 5 M four hours after injection and then fell exponentially. Administration by lumbar puncture occasionally produced epidural and subdural leakage; even with successful lumbar puncture, ventricular methotrexate concentration varied considerably from patient to patient despite similar doses. Administration by Ommaya reservoir more reliably produced adequate cerebrospinal fluid distribution than administration by lumbar puncture.

The overexpression of P-glycoprotein (P-gp) causes resistance to chemotherapy in many tumor types. Here, we report intercellular transfer of functional P-gp from P-gp-positive to P-gp-negative cells in vitro and in vivo. The expression of acquired P-gp is transient in isolated cells but persists in the presence of P-gppositive cells or under the selective pressure of colchicine. The intercellular transfer of functional P-gp occurs between different tumor cell types and results in increased drug resistance both in vitro and in vivo. Most importantly, the acquired resistance permits tumor cells to survive potentially toxic drug concentrations long enough to develop intrinsic P-gp-mediated resistance. P-gp transfer also occurs to putative components of tumor stroma, such as fibroblasts, raising the possibility that multidrug resistance could be conferred by resistant tumor cells to critical stromal elements within the tumor mass. This is the first report, to our knowledge, that a protein transferred between cells retains its function and confers a complex biologic property upon the recipient cell. These findings have important implications for proteomic analyses in tumor samples and resistance to cancer therapy.cell-cell communication ͉ multidrug resistance phenotype C ell-cell communication is an inherent feature of all life forms from bacteria to humans. A frequent result of cell-cell communication is collective population behavior that can potentially lead to complex phenotypes not observed in separate individual cells, e.g., in development or tumor formation (see, for example, ref.

No abstract