Tissue Platinum Concentrations Research Articles

Pilot study of neo-adjuvant intra-arterial (i/a) chemotherapy in patients with sarcomas of a head and neck

We developed a new technique of superselective intra-arterial chemotherapy for tongue cancer using a modified (1.35 mm) angiographic catheter. The catheter was confirmed to be inserted into the lingual artery by the new technique. We measured the platinum concentrations in resected tumour tissues after infusion of carboplatin (CBDCA) at 20 mg/m2 over 30 min from 30 min before tumour resection in 12 patients with cancer of the tongue (6 patients: superselective intra-arterial infusion; 6 patients: conventional intra-arterial infusion). The mean platinum concentration in tumour tissue was 10.5±1.2 μg/g wet, which was more than twice higher than, and significantly different from, 4.3±3.8 μg/g wet by the conventional intra-arterial infusion method. This new superselective intra-arterial infusion method allows direct infusion of the anticancer agent into the artery supplying the tumour and is expected to become a new therapeutic modality for cancer of the tongue.

Transarterial Chemoembolization Using Cisplatin Powder in a Rabbit Model of Liver Cancer

The purpose of this study was to investigate the pharmacological advantages of transarterial chemoembolization (TACE) with cisplatin powder for hypervascular hepatic tumors in animal experiments. VX2 tumors were transplanted to the livers of nine rabbits. Cisplatin (1 mg/kg) was infused into the proper hepatic artery. In the cisplatin-HAI group, cisplatin solution was infused. In the cisplatin-GS-TACE group, after infusion of cisplatin solution, gelatin sponge particles were used for embolization. In the cisplatin-Lp-TACE group, after infusion of a cisplatin powder and lipiodol (10 mg/ml) suspension, gelatin sponge particles were used for embolization. Before and after administration, platinum concentrations in plasma were measured. Using liver specimens that were excised 60 min after infusion, platinum concentrations in tumorous and nontumorous liver tissues were measured. The mean platinum concentration in tumorous tissue was 0.88 microg/ml for the cisplatin-HAI group, 1.23 microg/ml for the cisplatin-GS-TACE group, and 12.65 microg/ml for the cisplatin-Lp-TACE group. The platinum concentration for the cisplatin-Lp-TACE group was significantly higher than that for the cisplatin-HAI group (p = 0.004) and the cisplatin-GS-TAE group (p = 0.004). The mean platinum concentration in nontumorous liver tissue was 0.98 microg/ml for the cisplatin-HAI group, 1.13 microg/ml for the cisplatin-GS-TACE group, and 1.09 microg/ml for the cisplatin-Lp-TACE group; no significant differences were seen. At both 5 and 10 min after infusion, the platinum concentrations for the cisplatin-Lp-TACE group were lower than those for the other two groups. The present results suggest that TACE using cisplatin powder/lipiodol suspension and gelatin sponge for hypervascular hepatic tumors has a number of pharmacological advantages.

Pharmacokinetics and tissue distribution of novel traditional Chinese medicine-platinum anticancer agents in rats

The pharmacokinetics and tissue distribution profiles of a novel series of traditional Chinese medicine-platinum (TCM-Pt) compounds [Pt(C 8H 8O 5)(NH 2R) 2]: 1 (where R = H), 3 (R = CH 3) and 5 (R = C 6H 10), were studied in Sprague–Dawley rats following a single bolus intravenous (i.v.) injection. Platinum concentrations in total plasma, plasma ultrafiltrate, urine and tissues were measured by flameless atomic absorption spectroscopy. Pharmacokinetic studies showed that plasma concentrations of total and free platinum for the novel TCM-Pt compounds as well as cisplatin and carboplatin declined in a biexponential manner with a short distribution half-life ( t 1/2 α : 0.12–0.34 h). Compared with cisplatin, the novel TCM-Pt compounds had a longer elimination half-life ( t 1/2 β ), larger dose normalized area under the curve (AUC/D), larger volume of distribution at steady-state ( V ss), slower clearance (CL) of free platinum and higher percentage of cumulative urinary excretion (CUE), which can be attributed to their lower chemical reactivities. In tissues, the highest Pt concentrations were found in the kidney, followed by the liver and the lowest in the heart; no Pt was detected in the brain. Twenty-four hours after drug administration, platinum concentrations in tissues were significantly lower for the novel TCM-Pt compounds. These findings suggest that the novel compounds might afford higher clinical efficacy and reduced systemic side effects, when compared with cisplatin.

Comments on Total Platinum Concentration and Platinum Oxidation States in Body Fluids, Tissue, and Explants from Women Exposed to Silicone and Saline Breast Implants by IC−ICPMS

The paper by Lykissa and Maharaj (Lykissa, E. D.; Maharaj, S. V. M. Anal. Chem. 2006, 78, 2925-2933) comes to two main conclusions: platinum is found at elevated levels in women who have received breast implants, and the platinum is present in unusual oxidation states. The authors make clear their view that these are very surprising and disturbing results, both because of the quantity of platinum found and the association between higher oxidation states of platinum and toxicity of various types (sensitization-contact dermatitis, carcinogencity, among others). However, the conclusions arrived at by the authors are unsupported by the Experimental Section of the paper and the data that are reported there, and contravene the well-established chemistry of platinum.

Comments on Total Platinum Concentration and Platinum Oxidation States in Body Fluids, Tissue, and Explants from Women Exposed to Silicone and Saline Breast Implants by IC−ICPMS

The paper by Lykissa and Maharaj (Lykissa, E. D.; Maharaj, S. V. M Anal. Chem. 2006, 78, 2925-2933) purports to provide evidence that the urine of women with silicone breast implants contain 60 to over 1700 times more platinum in their urine that the urine of people with no known exposure to platinum. Further, they purport to show evidence that the platinum used in the manufacture of breast implants (Pt0) is converted by a unknown process to yield highly oxidized platinum species, stable in biological matrixes, up to and including Pt6+. This correspondence poses three questions associated with the work and directs the reader's attention to the data, which clearly show that the blood and urine platinum levels in implanted women and their healthy control group were not significantly different from one another.

Total Platinum Concentration and Platinum Oxidation States in Body Fluids, Tissue, and Explants from Women Exposed to Silicone and Saline Breast Implants by IC−ICPMS

Ion chromatography-inductively coupled plasma-mass spectrometry was used to determine the total platinum concentration and platinum oxidation states in samples from women exposed to silicone and saline breast implants. Samples included the following: whole blood, urine, hair, nails, sweat, brain tissue, breast milk, and explants. Mean Pt concentration in samples from women exposed to silicone breast implants were as follows: whole blood, 568.1 +/- 74.77 pmol/L (n = 9); urine, 1.77 +/- 0.847 mug/g of creatinine (n = 10); hair, 2.13 +/- 2.984 ng/g (n = 9); nails, 0.88 +/- 0.335 ng/g (n = 9); sweat, 1.90 +/- 1.691 ng/g (n = 9); breast milk, 1.09 +/- 0.316 mug/L (n = 6). Pt in explanted silicone breast implant gel (n = 9) occurred mainly in the +2, +4, and +6 oxidation states. Pt in whole blood (n = 7) and breast milk samples (n = 6) from women exposed to silicone breast implants occurred mainly in the +2 and +4 oxidation states. Saline breast implant fluid (n = 2) did not contain detectable levels of Pt. This is the most comprehensive report, to date, to show that women exposed to silicone breast implants have Pt levels that exceed that of the general population, and the first report, to date, to document the various Pt oxidation states present in samples from women exposed to silicone breast implants.

Platinum Concentration and Platinum Oxidation States in Body Fluids, Tissue, and Explants from Women Exposed to Silicone and Saline Breast Implants

Comments on a previous study necessitate a response on our part. Descriptive statistics were the most appropriate statistical tool for data analysis, given the small number of samples studied, and conclusions based on inferential statistics applied to the control subsets would have been inappropriate. Cross-study comparisons and drawing conclusions based on the published literature are commonly used standard methods for exposure analysis and interpretation. No oxidation artifacts were observed for the digestion conditions used. Since standards only exist for Pt 0, +2, and +4, Pt +1, +3, +5, and +6 were inferred. We hypothesize that the catalyst may be deteriorating due to the interaction at 37 degrees C with miscelles of mainly unsaturated fatty acids. The miscelles, through hydro-phobicity, may dissociate the aged Pt catalyst from the silicone cross-linkage and facilitate migration into the tissues. The conclusions, that the study was the most comprehensive report to show that women exposed to silicone breast implants have Pt levels that exceed that of the general population, and the first report to show oxidized forms of Pt present in samples from exposed women, are entirely supported by the data and are robust.

Effects of Irradiation Combined with Cis‐diamminedichloroplatinum (CDDP) Suppository in Rabbit VX2 Rectal Tumors

To decrease local recurrence and increase disease free survival, various preoperative therapies for patients with advanced rectal cancer have been studied. Cis-diamminedichloroplatinum (II) (CDDP) has become one of the most widely used cancer chemotherapeutic drugs. It has also been found to have radiosensitizing properties. In this experimental study, the efficacy of chemoradiotherapy using a novel CDDP suppository, and one with mixed micelles, was examined in a rabbit VX2 rectal tumor model. Rabbits were divided into four groups: control group, irradiation (R) group, CDDP suppository plus irradiation (CR) group, and mixed micelles plus CDDP suppository plus irradiation (CMR) group. Tumor growth ratios were reduced significantly in the CR and CMR groups as compared with the ratio in the control group. Microscopically, response rates of main tumors were 0%, 33.3%, 70.0%, and 91. 7%, respectively. The number of metastatic lymph nodes in the CR and CMR groups decreased significantly compared to the control group and the R group. The microscopic response rates of metastatic lymph nodes were 0%, 11.1%, 40.0%, and 41.7%, respectively. Lung metastases were observed in three rabbits in the R group, and in one rabbit in the CMR group. Tissue platinum concentrations both in tumors and in regional lymph nodes increased significantly when mixed micelles were used. Chemoradiotherapy using the CDDP suppository and mixed micelles was effective for local control in the rabbit VX2 rectal tumor model.

Comparative Studies of Platinum Concentrations in the Neck Tissues of Rats between Intraarterial and Intravenous Infusion of CDDP

We studied the comparative pharmacokinetics of platinum between intraarterial and intravenous CDDP infusion in male rats. Platinum concentrations in cervical tissues, serum, and tongue tissues were measured by a single intraarterial infusion or an intravenous infusion at a CDDP dose of 10 mg/kg. Intraarterial infusion was conducted through the left common carotid artery and intravenous infusion through the left external cervical vein. Tissues and blood samples were collected from bilateral sides every 30 minute for 120 minutes after completion of CDDP infusion. Platinum levels in serum showed no significant difference between the 2 routes. Platinum levels in tongue tissue showed a significant difference between the 2 routes favoring of intraarterial administration 30 minutes after infusion. Platinum levels in left cervical tissue following intraarterial administration peaked 90 minutes after infusion, significantly higher than that in right cervical tissue or that following intravenous administration. These findings suggest that CDDP transfers from target organs to neck tissues of the dosage side via the lymphatic duct, and that intraarterial infusion chemotherapy is effective at the target organ and at cervical lymph nodes or cervical tissues.

Digitonin enhances the antitumor effect of cisplatin during isolated lung perfusion

Background. The antitumor effect of isolated lung perfusion with cisplatin was limited because the intracellular platinum concentration did not increase sufficiently. To solve this problem, digitonin, a detergent, was chosen to increase cell permeability and enhance intracellular uptake and antitumor effect. This study was designed to investigate toxicity, pharmacokinetics, and efficacy of isolated lung perfusion with the combined use of digitonin and cisplatin in Fischer 344 rats. Methods. Systemic and local toxicities of isolated lung perfusion treatment were evaluated on the basis of body weight change, survival rate, and histologic findings. The maximal tolerated dose of digitonin was determined by assessing survival on day 21 after contralateral pneumonectomy, body weight change, and histologic findings. Pharmacokinetics were observed in a solitary lung tumor nodule model by measuring platinum concentration in tumor and normal lung tissue. The antitumor effect was evaluated by the number of tumor nodules in the left lung 21 days after isolated lung perfusion. Isolated lung perfusion was performed 7 days after 1.0 × 10 6 methylcholanthrene sarcoma cells were injected into the external jugular vein. Results. The maximal tolerated dose of digitonin was 20 μmol/L. Platinum concentration of tumor nodules in the digitonin-cisplatin–treated rats was 20% higher than in the cisplatin-only group (5.48 ± 0.64 μg/g tissue versus 4.50 ± 1.09 μg/g tissue; p = 0.067). The number of pulmonary nodules decreased significantly by digitonin use (1.3 ± 1.5 versus 9.7 ± 2; p < 0.0001). Conclusions. Isolated lung perfusion with digitonin and cisplatin in combination was performed safely and enhanced the antitumor effect. These drugs in combination show promise for enhancing the effect of clinical isolated lung perfusion.

Relationships Between Hydrophobicity, Reactivity, Accumulation And Peripheral Nerve Toxicity Of A Series Of Platinum Drugs

Previous work has shown platinum drugs to differ in their effects on the peripheral nervous system. To test whether their differential toxicity was due to differences in their partitioning into the peripheral nervous system, we correlated the hydrophobicity, reactivity, tissue accumulation and neurotoxicity of a series of eight platinum analogues. Neurotoxicity was detected by measuring sensory nerve conduction velocity (SNCV) in Wistar rats treated twice per week at the maximum tolerated dose. Tissue platinum concentrations were measured by inductively coupled plasma mass spectrometry. Hydrophobicity (log P) was measured using an octanol‐aqueous shake‐flask method. The half‐life of platinum drug binding to plasma proteins in vitro was determined. The cumulative dose causing altered SNCV ranged from 15 to &gt; 2050 micromol kg(‐1). Ranking of the compounds by their neurotoxic potency in rats (oxaliplatin &gt; R,R‐(DACH)PtC4 &gt; ormaplatin &gt; S,S‐ (DACH)PtCl4 &gt; S,S‐(DACH)Pt oxalato &gt; cisplatin &gt; carboplatin &gt; JM216) correlated with the frequency of neurotoxicity in patients (r &gt; 0.99, P &lt; 0.05). Ranking the compounds by their peripheral nerve accumulation was cisplatin &gt; carboplatin &gt; oxaliplatin &gt; R,R‐(DACH)PtCl4 approximate to S,S‐(DACH)PtCl4 and did not correlate with neurotoxicity. Log P ranged from −2.53 to −0.16 but did not correlate with neurotoxicity. Log P correlated inversely with platinum accumulation in dorsal root ganglia (r2 = 0.99, P = 0.04), sural nerve (r2 = 0.85, P = 0.025), sciatic nerve (r2 = 0.98, P = 0.0012), spinal cord (r2 = 0.97, P = 0.018) and brain (r2 = 0.98, P = 0.001). Reactivity correlated with neurotoxicity potency in rats (r2 = 0.89, P = 0.0005) and with the frequency of neurotoxicity in patients (r2 = 0.99, P = 0.0002). The hydrophilicity of platinum drugs correlates with platinum sequestration in the peripheral nervous system but not with neurotoxicity. Differences in the reactivity of platinum complexes accounts for some of the variation in their neurotoxicity.

Relationships between hydrophobicity, reactivity, accumulation and peripheral nerve toxicity of a series of platinum drugs.

Previous work has shown platinum drugs to differ in their effects on the peripheral nervous system. To test whether their differential toxicity was due to differences in their partitioning into the peripheral nervous system, we correlated the hydrophobicity, reactivity, tissue accumulation and neurotoxicity of a series of eight platinum analogues. Neurotoxicity was detected by measuring sensory nerve conduction velocity (SNCV) in Wistar rats treated twice per week at the maximum tolerated dose. Tissue platinum concentrations were measured by inductively coupled plasma mass spectrometry. Hydrophobicity (log P) was measured using an octanol-aqueous shake-flask method. The half-life of platinum drug binding to plasma proteins in vitro was determined. The cumulative dose causing altered SNCV ranged from 15 to > 2050 μmol kg−1. Ranking of the compounds by their neurotoxic potency in rats (oxaliplatin >R,R -(DACH)PtC4> ormaplatin >S,S -(DACH)PtCl4>S,S -(DACH)Pt oxalato > cisplatin > carboplatin > JM216) correlated with the frequency of neurotoxicity in patients (r> 0.99;P< 0.05). Ranking the compounds by their peripheral nerve accumulation was cisplatin > carboplatin > oxaliplatin >R,R -(DACH)PtCl4≈S,S -(DACH)PtCl4and did not correlate with neurotoxicity. Log P ranged from – 2.53 to –0.16 but did not correlate with neurotoxicity. Log P correlated inversely with platinum accumulation in dorsal root ganglia (r2= 0.99;P = 0.04), sural nerve (r2= 0.85;P = 0.025), sciatic nerve (r2= 0.98;P = 0.0012), spinal cord (r2= 0.97, P = 0.018) and brain (r2= 0.98, P = 0.001). Reactivity correlated with neurotoxicity potency in rats (r2= 0.89, P = 0.0005) and with the frequency of neurotoxicity in patients (r2= 0.99, P = 0.0002). The hydrophilicity of platinum drugs correlates with platinum sequestration in the peripheral nervous system but not with neurotoxicity. Differences in the reactivity of platinum complexes accounts for some of the variation in their neurotoxicity. © 2000 Cancer Research Campaign

Effects of lipo prostaglandin E 1 on distribution of cis-diamminedichloroplatinum in lung metastasis derived from Dunn osteosarcoma cell-inoculated mouse foot-pad

This study was designed to determine the effect of lipid microspheres containing prostaglandin E 1 (lipo PGE 1) on cis-diamminedichloroplatinum (CDDP) accumulation in primary and lung metastatic lesions. Sixty mice were divided into four groups, depending on whether or not an intra-foot-pad injection of Dunn osteosarcoma cells had been administered and on whether or not an intraperitoneal injection of lipo PGE 1 had been administered. CDDP was injected intraperitoneally into all the mice 6 weeks after the inoculation. Tumor colonies of spontaneous metastases in the left lung were found in 21 out of 30 tumor-inoculated mice at autopsy. Tissue platinum concentrations in the lungs with metastatic colonies and in the foot-pad tumors were significantly higher in the lipo PGE 1-administered mice than in those without treatment. Terminal deoxytransferase-mediated dUTP nick end labeling (TUNEL) assay showed marked localization of dying cells in the lung metastatic lesions of the lipo PGE 1-administered mice. The results of this study showed that pretreatment with lipo PGE 1 may augment the anti-tumor effects of CDDP at the tumor site.

口腔癌に対する浅側頭動脈より超選択的動注法を用いた化学療法の検討 組織内濃度と病理的効果

口腔癌に対する浅側頭動脈より超選択的動注法を用いた化学療法の検討 組織内濃度と病理的効果

Changes of tissue platinum concentration in human ovarian cancer-bearing nude mice who received an immunoconjugate consisting of an anti-cytokeratin-8 Mab and carboplatin.

Changes of tissue platinum concentration in human ovarian cancer-bearing nude mice who received an immunoconjugate consisting of an anti-cytokeratin-8 Mab and carboplatin.

New superselective intra-arterial infusion via superficial temporal artery for cancer of the tongue and tumour tissue platinum concentration after carboplatin (CBDCA) infusion.

We developed a new technique of superselective intra-arterial chemotherapy for tongue cancer using a modified (1.35 mm) angiographic catheter. The catheter was confirmed to be inserted into the lingual artery by the new technique. We measured the platinum concentrations in resected tumour tissues after infusion of carboplatin (CBDCA) at 20 mg/m2 over 30 min from 30 min before tumour resection in 12 patients with cancer of the tongue (6 patients: superselective intra-arterial infusion; 6 patients: conventional intra-arterial infusion). The mean platinum concentration in tumour tissue was 10.5 +/- 1.2 micrograms/g wet, which was more than twice higher than, and significantly different from, 4.3 +/- 3.8 micrograms/g wet by the conventional intra-arterial infusion method. This new superselective intra-arterial infusion method allows direct infusion of the anticancer agent into the artery supplying the tumour and is expected to become a new therapeutic modality for cancer of the tongue.

Pharmacokinetics of cisplatin with and without amifostine in tumour-bearing nude mice.

Amifostine (Ethyol, WR-2721) is in use in the clinic as a protector against platinum-induced toxicities. We have previously reported that amifostine induced a potentiation of the antitumour activity of carboplatin in human ovarian cancer xenografts. An influence of amifostine on the pharmacokinetics of carboplatin, resulting in higher platinum concentrations in plasma and tissues of the tumour-bearing nude mice, was thought to be the cause of enhancement of the antitumour activity. Therefore, the pharmacokinetics of cisplatin were investigated in tumour-bearing nude mice treated with cisplatin alone or in combination with amifostine. A significant increase in the area under the curve (AUC) of the total platinum concentration in mice treated with amifostine was only observed in the kidney (from 355 to 398 nmol h/g), whereas in the other tissues and plasma no significant changes were measured. The selective protection of normal tissues by amifostine was confirmed by a decrease in the AUC of the cisplatin-DNA adduct levels in normal tissues. The decrease was only significant in the liver (282-240 fmol h/microgram DNA), whereas in tumour tissue a slight increase in the AUC of the cisplatin-DNA adducts could be detected (91.3-110.1 fmol h/microgram DNA). The minor influence of amifostine on the pharmacokinetics of cisplatin may be the reason why amifostine did not potentiate the antitumour activity of cisplatin. The influence of amifostine on cisplatin-DNA adduct levels in normal tissues versus tumour tissues is further evidence for the usefulness of this toxicity modulator in cancer patients.

Pilot study for preoperative administration of 1-OHP to patients with advanced scirrhous type gastric cancer

A new DACH platinum complex, l-OHP, was developed by Kidani as an anticancer agent. A clinical trial took place in Europe which demonstrated its therapeutic efficacy for colorectal cancer. An effective treatment, especially chemotherapy for patients with a advanced scirrhous type gastric cancer, has not yet been established. An in vitro study showed that l-HOP inhibited cell growth in human gastric cancer cell lines. Our pilot study determined the efficacy of preoperative administration of l-OHP, 67 mg/m2 to 100 mg/m2, every 2-3 weeks, for two to three cycles, in five patients with this disease (Stage III and IV) roentogenoscopically and histologically. The platinum concentration in the tissues was also measured. By X-ray examination of the stomach at the time of pre- and post-administration of l-OHP, extension of the lesional gastric wall was observed. Histologically three Grade 2 responses and two Grade 1a responses were obtained according to the criteria presented by Japanese Research Society for Gastric Cancer. The mean platinum concentrations in the lesional tissues were 0.98 ppm and 0.5 ppm in the patients administered l-OHP for three and two cycles respectively. There was no toxicity that prevented surgery. These preliminary results showed the possibility that 1-OHP would be effective for patients with advanced scirrhous type gastric cancer as a neoadjuvant therapy.

Continuous local injection of carboplatin into the uterine cervix for cervical and endometrial cancer: preliminary study.

Platinum compounds are thought to be concentration- and time-dependent, but intravenous (i.v.) administration does not afford prolonged high platinum concentration in tumor tissue. In order to examine the influence of long-term local continuous (LC) injection of carboplatin, a pharmacokinetic study was performed. Twenty-six patients with uterine cancer were included. I.v. administration (11 patients): carboplatin (210 mg) was given i.v. and samples of target tissue were obtained at operation about 2 or 24 h after administration. LC administration (15 patients): the 21-gauge needle was implanted at the uterine cervix, and carboplatin was injected continuously (30 mg/day) for 3, 7 or 14 days using an external pump. The tissue platinum concentration was measured in the pelvic organs. The mean platinum levels at the cervix and vaginal wall in the LC (7 days) group were higher than those in the i.v. (2 h) group (p < 0.01). With LC injection, sustained platinum levels were maintained in the pelvic organs for a long time, with very few side effects. LC injection may be advantageous on the basis of pharmacokinetics.

A study on the relationship between sensitivity to CDDP and inducibility of metallothionein and glutathione of genitourinary tumors

In this paper we demonstrate the relationship between the antitumor activity of cis-diamminedichloroplatinum (II) (CDDP) and inducibility of metallothionein (MT) and glutathione (GSH) of genitourinary tumors. The chemosensitivity test was performed in athymic mice bearing tumors derived from the human tumor cell lines: ACHN (renal cell carcinoma), NMB-1 (urinary bladder transitional cell carcinoma), and NMT-1 (testicular embryonal cell carcinoma). A single dose of CDDP (25 mumol/kg body weight), was administered i.p. to athymic tumor bearing mice. Concentrations of platinum, MT, and GSH were measured in organ and tumor homogenates 24 h after CDDP administration. We observed that tumors derived from NMB-1 and NMT-1 were very sensitive to CDDP, but ACHN derived tumors were resistant to CDDP. Measurement of platinum concentrations in tumor tissues revealed no correlation to the observed chemosensitivities of the tumors. Furthermore, 24 h after CDDP administration, the levels of MT and GSH in NMB-1 and NMT-1 derived tumors were lower them or equal to those of control mice. In contrast, mice bearing tumors derived from ACHN exhibited a 1.7-fold and a 2.1-fold increase in MT and GSH, respectively, as compared to control mice. These findings suggest that the inducibility of MT and GSH in tumor tissues following CDDP administration may be a contributing factor in the development of CDDP resistance in renal cell carcinoma.