Abstract 2453: Soluble B7H3 has a potential of novel serum biomaker for colorectal cancer

Abstract

Abstract B7H3 (also known as CD276, an immune checkpoint molecule) is aberrantly over expressed in many types of cancer. Recently, several reports indicate a crucial role for B7H3 in promoting carcinogenesis and metastasis. We investigated whether concentration of the soluble B7H3 could be used as a new prognostic predictor of colorectal cancer by measuring serum level of B7H3. Recently we established a new mAb to B7H3 and developed sandwich ELISA-system detecting human serum B7H3 with high sensitivity and specificity. Measuring the levels of B7H3 in the serum specimens of colorectal cancer donors, we examined the usefulness of B7H3 as a novel biomarker for colorectal cancers. We tested the blood from the 82 donors of colorectal cancers and 9 healthy donors who agreed in writing to this research, just before the operation. The mean value + 2SD in 9 healthy donors was set as the cutoff value. We classified cancer patients into 2 groups with high value of B7H3 and low value of B7H3. We also analyzed the relationships between serum B7H3 levels and disease-free survival (DFS) and overall survival (OS). Serum B7H3 levels were also compared with diagnostic biomarkers such as CEA and CA19-9. B7H3 immunostaining was also performed on tissue samples. The serum levels of B7H3 in patients with colorectal cancer were significantly higher than those of healthy donors. However, there were no correlation between B7H3 and other diagnostic markers CEA and CA19-9. Regarding DFS, the higher value group of serum B7H3 showed a tendency for DFS to decrease in Stage II and III. Regarding OS, there was no significant difference of serum levels of B7H3 in Stage I and IV cases, however, in Stage II and III, OS decreased significantly in the high B7H3 group. In B7H3 immunostaining, the tissue was not sufficiently stained. These data indicate that serum B7-H3 should be useful for novel biomarker for a rationale of disease monitoring and prognosis of colorectal cancer. Citation Format: Akihiro Koizumi, Tomoaki Ito, Kazunori Kato, Takumi Iwasawa, Tomoyuki Kushida, Koichi Sato, Chikako Okamoto. Soluble B7H3 has a potential of novel serum biomaker for colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2453.