Increased serum type IV collagen 7-S levels in patients with hepatic metastasis

The purpose of this study was to assess serum type IV collagen 7-S domain (IV 7-S) levels in colorectal cancer patients with hepatic metastasis and to investigate the relation between serum IV 7-S levels and type IV collagenase activities in tumor tissue.

Tissue type IV collagenase activity and serum IV 7-S were measured in 50 colorectal cancer patients without hepatic metastasis and in 26 patients with hepatic metastasis.

Type IV collagenase showed significantly higher activities in colorectal cancer (n = 36) than in colorectal normal mucosa (n = 36) (p < 0.001), but significantly lower activities were shown in the hepatic metastatic tumor (n = 18) than in the primary tumor (n = 36) and normal liver tissue (n = 18) (p < 0.001). No significant correlation was found between type IV collagenase activities in the tumor and serum IV 7-S levels. Colorectal cancer patients with hepatic metastasis (n = 26) had significantly higher serum IV 7-S levels than those without hepatic metastasis (n = 50) (p < 0.001). Moreover, serum IV 7-S levels correlated significantly with hepatic metastatic tumor volume in patients with synchronous (r = 0.719, p < 0.001, n = 26) and in patients with metachronous (r = 0.910, p < 0.001, n = 16) hepatic metastasis.

We suggest that serum IV 7-S levels may increase in hepatic metastasis, not by the degradation of type IV collagen in the primary and secondary tumors, but by the enhanced production of type IV collagen responsive to hepatic metastasis. The measurement of serum IV 7-S levels might be a useful tumor marker of hepatic metastasis reflecting hepatic metastatic tumor volume.