| Summary: | 碩士 === 國立臺灣大學 === 職業醫學與工業衛生研究所 === 101 === Background：The upper tract urothelial carcinoma accounted for more than half of kidney cancer in Taiwan, and its incidence was higher than those of the western countries. Previous studies indicated that chromium, manganese, copper, arsenic, cadmium, lead and nickel may cause adverse health effects in kidney and urinary tract. People with deficit in arsenic metabolism tended to develop peripheral vascular disease after exposing to high level of arsenic. The goals of this study were set to explore the association between the occurrence of kidney cancers and the concentrations of arsenic or other relevant metals in various kidney tissues, and between the occurrence of kidney cancers and the efficacy of arsenic metabolism in human body.
Methods：One hundred and two patients with excision surgery for kidney cancers, including renal cell carcinoma, upper tract urothelial cancer, and controls were recruited from the National Taiwan University Hospital. Urine samples and renal cortex, pelvis samples and urothelial tract samples from the excised organs were collected from each study subject. Concentrations of chromium, manganese, copper, arsenic, selenium, strontium, cadmium, lead, nickel in the collected tissue and urine samples were analyzed by inductively coupled plasma mass spectrometer while the levels of trivalent arsenic, pentavalent arsenic, monomethylarsonic acid, dimethylarsinic acid in urine samples were analyzed with high performance liquid chromatography along with inductively coupled plasma mass spectrometry. Demographics and environmental metal exposure factors of the study subjects were collected by questionnaire administration in order to compare their effects on the study metal levels in urine and kidney tissue samples.
Results: Average cadmium concentration in urine samples of the renal cell carcinoma cases, 6.77 ± 13.3 μg/L, was higher than that of upper tract urothelial cancer cases, 2.30 ± 4.60 μg/L (p <0.05). The average concentrations of manganese and copper in the renal cortex in the cases of renal cell carcinoma were significantly higher than those of the upper tract urothelial cancer cases. Average manganese and copper concentrations in renal cortex samples of the renal cell carcinoma cases were 3.24 ± 2.05 μg/g and 9.51 ± 3.98 μg/g, respectively, both significantly higher than those of the upper tract urothelial cancer cases; 2.07 ± 1.52 μg/g and 6.10 ± 4.84 μg/g, respectively. In addition, concentrations of copper, selenium, cadmium and lead in tumor tissues of the renal cortex samples of the renal cell carcinoma cases were all lower than those in the adjacent normal tissues with differences of 6.21 ± 6.46 µg/g (p=0.01), 2.65±2.81 µg/g (p=0.01), 87.5±73.8 µg/g (p=0.003), 1.97±2.69 µg/g (p=0.04). Furthermore, there was no difference in total arsenic levels in various renal tissue samples, and in proportion of arsenic species, PMI and SMI index for urine samples, among the renal cell carcinoma cases, the upper tract urothelial carcinoma cases, and the controls.
Conclusions: Previous studies reported that exposure to chromium, manganese, copper, arsenic, cadmium, lead and nickel might be associated with urinary tract related diseases. However, although this study found there were differences in urinary cadmium concentration and in manganese, copper concentrations in renal cortex samples between renal cell carcinoma cases and upper tract urothelial cancer cases, there was no difference observed for total urinary arsenic levels and urinary arsenic species among the renal cell carcinoma cases, the upper tract urothelial cancer cases and the control cases. Therefore, results of the present study might not be appropriate to support the use of total urinary arsenic level and urinary arsenic species levels as indicators for renal cancer related risk. Besides, the concentrations of copper, selenium, cadmium, lead in tumor tissue of the renal cell carcinoma cases were found higher than those of their adjacent normal tissue. The mechanism leading to such metal concentration gradient between tumor and normal tissues in kidney is deserved of future study for further exploration.
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