Oral and oropharyngeal squamous cell carcinoma (OSCC) together rank as the sixth most common cancer worldwide, it is the most common cancer in some low- and middle- income countries (LMICs). The poor survival rate in LMICs and rural regions in developed countries is mainly due to late diagnosis and the resultant progression of disease to an advanced stage at diagnosis. Motivated by the successes in the two different NIH UH2/UH3 projects for detecting and treating pre- and early oral cancers, Light Research Inc (LRI) proposes to develop and commercialize a new integrated mobile oral-cancer screening and treatment (MOST) system, optimized for low-resource settings (LRS). It combines dual-modal oral cancer screening technology and photochemistry-based, FDA approved photodynamic therapy (PDT) modality. We will first develop the MOST system (Aim 1) and then demonstrate the imaging and treatment performance of MOST system with murine subcutaneous xenograft model (Aim 2). This project is significant because early diagnosis of oral cancers and timely treatment can reduce disease progression, reduce morbidity and mortality, and cut costs. It addresses the major barrier to screen high-risk population and treat patients with high risk oral premalignant and malignant lesions (OPML) and early-stage oral cancer in LRS.