Preliminary application of 125 I–nivolumab to detect PD-1 expression in colon cancer via SPECT

The precise detection of PD-1/PD-L1 biomarkers helps to predict the prognosis of corresponding immunotherapy. 125I-labeled nivolumab targeting activated immune cells infiltrating the tumorous tissues was developed to evaluate the expression of PD-1 immune checkpoints. SPECT images indicated that 125I–nivolumab preferentially targeted to tumor-surrounded immune cells. This radiotracer can dynamically and quantitatively characterize the in vivo expression of immune checkpoints for colorectal cancer, thereby potentially enabling the early screening of patients, monitoring the efficacy of treatment, and assessing potential immunotoxicity.