Background: A clinically significant tumor marker is important for the diagnosis of colorectal cancer (CRC) and its management after the treatment. Laminin (Ln)-
γ2 is expressed in various types of malignant carcinomas, indicating that it may be a potential serum biomarker. We recently developed a quantitative ELISA assay to determine serum Ln-
γ2 levels using the monoclonal antibody to human Ln-
γ2 selectively.
Methods: Using our previously developed ELISA assay, we examined the serum Ln-
γ2 levels in 78 serum specimens from 51 healthy volunteers, 8 patients with benign disease, and 19 CRC patients. Using chemiluminescent immunoassays, we measured carcinoembryonic antigen (CEA) and CA19-9 simultaneously and compared the diagnostic value of a combination of Ln-
γ2 with each of these markers.
Results: The medians of the serum levels of Ln-
γ2 in healthy controls, benign disease patients, and CRC patients were 241.9 pg/mL, 138.8 pg/mL, and 323.0 pg/mL, respectively. Significantly higher Ln-
γ2 levels were observed in patients with CRC than in the other two groups. The optimal cutoff value for Ln-
γ2 that would distinguish CRC cases from non-malignant cases was 315.8 pg/mL. We observed elevated Ln-
γ2 levels (>315.8 pg/mL) in 57.9% of the patients with CRC. The positive rate in patients with CRC for the combination of Ln-
γ2 and CEA was 78.9%, higher than that for either of those markers alone (57.9% and 52.6%). The positive rate in CRC patients was high for all markers in advanced stage CRC, but that for CEA and CA19-9 in Stage I/II was low. On the other hand, the positive rate for Ln-
γ2 in Stage I/II was high at 50.0%.
Conclusions: Serum Ln-
γ2 may be a novel biomarker for CRC that can be used along with existing tumor markers for CRC detection.
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