|
Tumor-associated extracellular vesicles (TEVs), which represent a unique kind of inter-cellular communication carrier, have been found to play vital roles in directing the invasion and metastasis of tumor cells. However, because the human tumor microenvironment and TEVs significantly degrade or lose vitality over relatively brief periods of time after breast cancer surgical excision, lab-based studies with fresh human tissue specimens cannot provide accurate TEV information. By designing and building a portable label-free nonlinear imaging system, we have been able to conduct intraoperative imaging of fresh, unstained breast tissue specimens immediately after excision. Various features of the breast tumor microenvironment from multimodal nonlinear images were characterized to indicate tumor progression, invasiveness, and tumor grade, such as tumor-accommodating collagen structure visualized using second harmonic generation imaging, fibroblasts shown by two photon auto-fluorescence, and TEVs highlighted using third harmonic generation imaging. In particular, we found TEV count as a promising biomarker of tumor aggressiveness and margin distance. A decreasing trend of TEV counts with larger margin distance and lower cancer aggressiveness grades was revealed among 18 breast cancer cases. In addition, clear differences in TEV counts between images collected from breast cancer cases and healthy breast reduction cases, in another aspect, validate the potential of identifying TEVs using our imaging method. Acquisition and interpretation of these intraoperative image data not only provided assessment of the human tumor microenvironment, but also offered the potential to intraoperatively assess tumor margin distance and determine tumor aggressiveness.
|
