Altered B cell immunoglobulin signature exhibits potential diagnostic values in human colorectal cancer.

Antibody-secreting B cells have long been considered the central element of gut homeostasis; however, tumor-associated B cells in human colorectal cancer (CRC) have not been well characterized. Here, we show that the clonotype, phenotype, and immunoglobulin subclasses of tumor-infiltrating B cells have changed compared to adjacent normal tissue B cells. Remarkably, the tumor-associated B cell immunoglobulin signature alteration can also be detected in the plasma of patients with CRC, suggesting that a distinct B cell response was also evoked in CRC. We compared the altered plasma immunoglobulin signature with the existing method of CRC diagnosis. Our diagnostic model exhibits improved sensitivity compared to the traditional biomarkers, CEA and CA19-9. These findings disclose the altered B cell immunoglobulin signature in human CRC and highlight the potential of using the plasma immunoglobulin signature as a non-invasive method for the assessment of CRC.