Decreased green autofluorescence in cancerous tissues is a potential biomarker for diagnosis of renal cell carcinomas.

This study primarily focuses on the potential sources of autofluorescence, including keratins (KRT) encoded by KRT1, KRT7, and KRT8, to investigate their contributions to the differences in autofluorescence between cancerous tissues and adjacent non-tumor tissues, as well as their potential for real-time diagnosis of RCC. First, the autofluorescence of renal cell carcinoma (RCC) tissues under 488 nm laser excitation was observed and compared with the autofluorescence of neighboring non-tumor tissues. Then, the effect on the autofluorescence intensity was analyzed by knocking down the KRT1/KRT7 gene. In addition, autofluorescence data were collected from 174 pairs of tumor and adjacent non-tumor tissue samples (from 60 RCC patients). Diagnostic performance was evaluated using ROC analysis to determine the threshold value for tumor autofluorescence intensity. Under 488 nm laser excitation, the intensity of green autofluorescence in cancerous tissues of RCC patients was significantly lower than that in non-tumor tissues. Further analysis showed that KRT1 knockdown resulted in a 73% reduction in autofluorescence intensity, suggesting that KRT1 plays a key role in the reduced autofluorescence observed in tumor tissues. In addition, analysis of autofluorescence data from 174 tumor and adjacent non-tumor tissue samples showed an AUC of 0.880 for ROC analysis, a diagnostic sensitivity and specificity of 0.843 and 0.835, respectively, and a threshold value of 27.45 for using tumor autofluorescence intensity. KRT1 is a major contributor to the tumor autofluorescence observed in RCC. An autofluorescence-based diagnostic model facilitates real-time assessment of surgical margins during partial nephrectomy, thereby potentially improving surgical success rates.