Monitoring the progression of lobular breast carcinoma using multiphoton microscopy

Atypical lobular hyperplasia and lobular carcinoma in situ are often considered as non-obligate precursor lesions to invasive lobular carcinoma (ILC). The visualization of cell morphology changes during the progression of a lobular carcinoma has an important role in the real-time diagnosis of tumor staging. Also, monitoring the changes of collagen during tumorigenesis is vitally important for studying the efficiency of cancer cells entering surrounding tissues, as well as the metastatic potential. In this study, we compare the imaging quality of histological sections without staining and the haematoxylin and eosin (H&E)-stained samples of normal breast lobules by using multiphoton microscopy (MPM) based on two-photon excited fluorescence and second harmonic generation. It was found that the H&E-stained samples have a higher imaging contrast than the histological sections. Furthermore, we prove that MPM can be used not only to reveal changes in the tissue microstructure but can also provide information about collagen that cannot be rendered directly by the H&E-stained sample. Using Fourier analysis, we found significant differences in the morphology of collagen during the progression of the lobular carcinoma. In addition, at the invasion front of the ILC, we found that collagen was arranged parallel to the fat boundary by MPM. These results indicate that MPM can provide insights into trends of collagen reorganization and histological changes throughout breast tumor development and has potential as a clinical tool for evaluating the pathological character of breast cancer.