Although histological evaluation is the current gold standard for ECTI assessment, it requires biopsy, tissue fixation and sectioning, and does not allow noninvasive visualization or study. Other methods of imaging, such as electron microscopy, have required both fixation and removal of the epithelium to visualize the ECTI and abnormalities in structure which accompany precancer. The method of optical Enzalutamide CYP17 inhibitor coherence tomography, with axial resolution range of 7�C17 ��m has been used to obtain cross-sectional optical images to encompass both the epithelium and lamina propria in a noninvasive manner and has been investigated in the context of oral dysplasia in several studies. Two of these studies have used advanced segmentation algorithms to delineate the oral epithelium-lamina propria boundary demonstrating the potential for extraction of ECTI features using this modality, however no known OCT studies have extracted ECTI-specific parameters or made direct quantitative comparisons with histology to validate ECTI shape features. In this study we apply nonlinear optical microscopy by the modalities of multiphoton autofluorescence microscopy and second harmonic generation microscopy to image the ECTI as these imaging modalities are capable of performing deep tissue in-vivo imaging at high resolution enabling layer-resolved imaging of tissue EX 527 company morphology at subcellular level. Autofluorescence in label-free MPAM is typically used for morphometric and biochemical analysis of intact tissue. SHG microscopy can be used to image ECM components with noncentrosymmetric molecular structure comprising of fibrillar collagen. Together, these two imaging modalities can provide information about the epithelium as well as the underlying lamina propria architecture on a microscopic level. Further we believe they can be used to specifically delineate the ECTI and features associated with neoplasia that are unique to that interface. The ability to delineate and quantify parameters of ECTI would be useful in studies investigating the interplay between epithelium and lamina propria and examination of alterations relative to each other in neoplasia. Because the BM refers specifically to the layer consisting of Type IV collagen separating the epithelium and lamina propria and itself is not necessarily distinct in MPAMSHGM, we use the term ECTI to describe the uppermost lamina propria interface lining the BM visible by SHGM. The purpose of this study was to evaluate whether changes in the ECTI which occur with dysplasia are visible by MPAM-SHGM and to develop a quantitative approach to describe these early changes using a hamster model of oral carcinogenesis for establishing the concept.