We previously suggested that laminin plays an important role in metastasis of renal cell carcinoma (RCC) since the serum laminin level was higher in RCC patients that in healthy controls and also significantly higher in RCC patients with metastatic lesions than in those with only primary lesions.
In this study, we investigated of the serum laminin level in a larger number of RC C patients and conducted basic studies assuming that tumor cells produce and excrete serum laminin, thereby affecting the clinical course.
The serum laminin level was higher in RCC patients than in the healthy controls and tended to decrease after nephrectomy. The serum laminin level was significantly higher in patients with metastatic lesions than in those with only primary lesion. Conversely, no clear correlations existed between the serum laminin level and the tumor size, degree of histological malignancy or degree of tumor invasion. The serum laminin concentration tended to be higher in renal venous blood than in renal arterial blood. The supernatant of tumor tissue homogenates contained much laminin, Which correlated positively with the serum laminin concentration. Moreover, the laminin concent ration in the renal carcinoma cell culture supernatant increased with time. Therefore, RCC was surmised to be a laminin-secreting tumor.
The positive correlation between the tumor tissue and serum laminin concentration suggests that a patient's serum laminin level reflects laminin production capacity. The higher serum laminin level in RCC patients with metastatic lasions, suggests that metastasis of RCC is closely related to each patient's laminin production, which can be estimated from the laminin level in the peripheral blood.
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