Early Identification Of Breast Tumor Based On Multiphoton Microscopy

Breast cancer is the most common cancer in women, which has threatened women's health and survival seriously. It is well known that detection and treatment of early lesions is crucial for lowering the death rate of breast cancer, as well as improving the quality of life of the patients. However, the spatial resolution of current noninvasive clinical techniques is not high enough to visualize pathological changes at the early stage during breast tumor progression. Thus, it is crucial to establish a noninvasive imaging technique that allows for in vivo monitoring of morphological alterations comparable to histopathology.In recent years, multiphoton microscopy (MPM) has opened up new possibilities for tissue imaging at the molecular level, which facilitates the early identification of malignant tumor. MPM has many significant advantages including enhanced axial depth discrimination, enhanced penetration depth in scattering samples, and reduced overall specimen photodamage and photobleaching, because it uses a near-infrared light source. In this work, we focus on the study of early identification of breast tumor based on MPM.First, to achieve the differentiation of neoplastic and non-neoplastic breast lesions, MPM was used to investigate normal breast tissue and several non-neoplastic breast lesions. It was found that nicotinamide adenine dinucleotide hydrogen (NADH) and flavin adenine dinucleotide (FAD) in cells and vessels can generate strong TPEF signals, collagen fibers in basement membrane can emit strong SHG signals, and collagen bundles in stroma have comparable TPEF and SHG signals. Based on the TPEF and SHG signals of these intrinsic fluorescent molecules, MPM can reveal different microstructure of breast tissue. It was also found that MPM can provide cellular and subcellular details to identify different non-neoplastic breast lesions including fibroadenoma, breast cysts, and lobular hyperplasia. In particular, there is significant difference in the collagen content and orientation among different non-neoplastic breast lesions, as well as the circle length of acinus. The related main results have been published in Journal of Microscopy, 258(1),79-85,2015 (SCI, IF=2.3) and Proceedings of SPIE,9230,9230N-1,2014 (EI).Second, MPM was used to investigate two common neoplastic breast lesions, namely breast ductal carcinoma in situ (DCIS) and invasive breast ductal carcinoma (IDC). The results showed that MPM has the capability to identify three different architectural subtypes of DCIS (solid, cribriform and comedo), and evaluate tumor staging during IDC progression (low-grade and high-grade staging). The results also suggested that MPM can establish the diagnostic features, including nuclear area, collagen density, and cellular metabolism, to quantitatively differentiate normal and cancerous breast tissue. The related main results have been published in Journal of Physics D:Applied Physics,48,405401,2015 (SCI, IF=2.7) and Lasers in Medical Science,30,1109-1115,2015 (SCI, IF=2.5).Third, a new approach combing qualitative MPM imaging and quantitative image analysis was developed to monitor the progression of breast ductal carcinoma thoroughly. The results showed that MPM can identify the different stages during breast ductal carcinoma progression, including normal duct, non-invasive ductal carcinoma, and invasive ductal carcinoma. It was also found that this technique can establish a quantitative link between several morphological alterations and breast ductal carcinoma progression, including nuclear area, circle length of basement membrane, and collagen density. These quantitative characterization parameters can serve as intrinsic indicators to effectively evaluate the progression of mammary ductal carcinoma. The related main results have been published in Journal of Biomedical Optics,20(9),096007,2015 (SCI, IF=2.8) and Proceedings of SPIE,9303,93032P,2015 (EI).Last, MPM was used to image lymph node, including both benign human axillary lymph nodes and nodes containing metastatic breast carcinoma, for detecting breast cancer axillary lymph node metastases. It was found that MPM has the capability to reveal nodal structures such as cortex and intranodal vessel, and differentiate malignant tumor cell from lymphocyte in metastatic lymph node. The results open the new way for the identification of metastatic involvement of lymph nodes in breast cancer. The related papers "Distinction of tissue types in axillary lymph node histology based on multiphoton microscopy" and "Detection of breast cancer axillary lymph node metastases using multiphoton microscopy" have been submitted.In summary, MPM was used to investigate the early identification of breast tumor, monitor the progression of mammary ductal carcinoma, and detect the metastatic involvement of lymph nodes in breast cancer in this thesis. The results obtained in this thesis will provide the groundwork for the further use of MPM to perform a realtime noninvasive diagnosis of early breast lesions in clinic.