CD24-Targeted NIR-II Fluorescence Imaging Enables Early Detection of Colorectal Neoplasia.

Colorectal cancer continues to be a major health issue even though screening methods have facilitated early detection. Despite the high sensitivity of white-light colonoscopy, it frequently overlooks invasive flat or depressed lesions, which can lead to the development of larger, advanced tumors. Fluorescence molecular imaging offers a promising approach for early tumor detection by targeting specific molecular characteristics of lesions. CD24 is upregulated during the adenoma-to-colorectal cancer transition, providing a potential target for fluorescence molecular imaging. In this study, we developed a second near-infrared window (NIR-II) fluorescent probe with a high affinity for CD24 and evaluated its efficacy and targeting ability in cellular models, murine models, and clinical samples of colorectal cancer. CD24 expression was elevated in 76% of adenomas and 80% of colorectal cancers. In a colitis-associated cancer mouse model, NIR-II imaging with the CD24-targeted probe achieved a significantly higher tumor-to-background ratio compared with conventional NIR-I imaging. The probe demonstrated exceptional sensitivity (92%) and specificity (92%) for detecting colorectal cancer, including small lesions less than 1 mm in size. This led to the identification of precancerous lesions missed by white-light detection and lesions missed by NIR-I imaging. Moreover, ex vivo human tissue incubation with the probe supported the potential for intraprocedural lesion identification via topical probe application during colonoscopy. In conclusion, this study successfully demonstrates the potential of CD24-targeted NIR-II imaging for identifying colorectal neoplasia, highlighting its significance for early colorectal cancer detection in the gastrointestinal tract. Significance: Overexpression of CD24 in colorectal dysplasia provides the opportunity to use an NIR-II fluorescent probe targeting CD24 to detect colorectal neoplasms, including invisible lesions that are missed by white-light colonoscopy.