Effect of intraperitoneally administered recombinant murine granulocyte-macrophage colony-stimulating factor (rmGM-CSF) on the cytotoxic potential of murine peritoneal cells

We studied the effect of recombinant murine granulocyte–macrophage colony-stimulating factor(rmGM-CSF) on the cytotoxic potential of murine peritoneal cells. Mice received rmGM-CSF intraperitoneally using different dosages and injection schemes. At different time points after the last injection, mice were sacrificed, peritoneal cells isolated and their tumour cytotoxicity was determined by a cytotoxicity assay using syngeneic [methyl-3H]thymidine-labelled colon carcinoma cells. Also, the cytotoxic response to a subsequent in vitro stimulation with lipopolysaccharide was determined. Upon daily injection of 6000–54 000 U rmGM-CSF over a 6-day period, the number of peritoneal cells increased over ten fold with the highest rmGM-CSF dose. Increases in cell numbers was mainly due to increases in macrophage numbers. Upon injection of three doses of 3000 U rmGM-CSF per day for 3 consecutive days, the number of macrophages remained elevated for minimally 6 days. Although the peritoneal cells from rmGM-CSF-treated mice were not activated to a tumoricidal state, they could be activated to high levels of cytotoxicity with an additional in vitro stimulation of lipopolysaccharide. Resident cells isolated from control mice could be activated only to low levels of tumour cytotoxicity with lipopolysaccharide. Tumour cytotoxicity strongly correlated with nitric oxide secretion. When inhibiting nitric oxide synthase, tumour cell lysis decreased. Thus, the expanded peritoneal cell population induced by multiple injections of rmGM-CSF has a strong tumour cytotoxic potential and might provide a favourable condition for immunotherapeutic treatment of peritoneal neoplasms. © 1999 Cancer Research Campaig

Residual masses after chemotherapy for metastatic testicular cancer:The clinical implications of the association between retroperitoneal and pulmonary histology

Purpose: We determined the need and sequence of retroperitoneal lymph node dissection and thoracotomy in patients with nonseminomatous testicular cancer, and with residual retroperitoneal and pulmonary masses after chemotherapy. Materials and Methods: We studied 159 patients undergoing retroperitoneal lymph node dissection and a thoracotomy following cisplatin based induction chemotherapy for metastatic testicular nonseminomatous germ cell tumor. Several well-known predictors for residual histology (necrosis, mature teratoma and cancer) were evaluated. Results: As expected, necrosis was found more often at retroperitoneal lymph node dissection if the primary tumor was negative for teratoma, the residual mass was small or the decrease in size was great. Contrary, neither residual mass size nor the decrease in size was predictive of the histological status of the residual lung lesion. Histological findings in the retroperitoneum and lung were strongly correlated, such that necrosis at retroperitoneal lymph node dissection was associated with an 89% probability of necrosis in the lung. Conclusions: Retroperitoneal lymph node dissection should be performed before thoracotomy is considered, since the histological status at dissection is a strong predictor of that at thoracotomy