Tryptophan, collagen, NADH, and flavin are key molecules in cancer diagnose using spectroscopy.2–4 For breast cancer, the most common grading system used in the United States is the Scarff-Bloom-Richardson (SBR) system,17 which is a breast cancer staging system that examines the cells and tissue structures of tumors to determine how aggressive and invasive the cancer is depending on three features: (1) The percent of the tumor makes the tissue structures change. In cancer, the tissue structures usually become less orderly; (2) the numbers of mitotic figures (dividing cells) observed in a certain magnitude microscope field. One of the hallmarks of cancer is that cells divide uncontrollably; and (3) the nonuniformity of the cell nuclei. The cancerous cells have larger, irregular, and darker cell nuclei than that of normal breast duct epithelial cells.17 Each of these features is assigned a score ranging from 1 to 3. The lowest score 3 () is given to well-differentiated tumors with best prognosis while the highest score 9 () for poorly differentiated tumor is the worst prognosis.17 According to the features described by the SBR system, higher cell density, uncontrollable cells-dividing, and nonuniform larger cellular nuclei are characteristics for cancerous breast cells; therefore the changes of fluorescence from the main fluorophores inside cells (e.g., tryptophan, NADH, and flavin) should be expected. The primary fluorophore in the breast tissue extracellular matrix is type I collagen.18 For invasion and subsequent metastasis, tumor cells degrade the surrounding extracellular matrix, which is composed mainly of type I collagen.18 Understanding these changes during breast cancer evolution is critical to reveal the contributions of the biochemical components in tissue for the spectroscopic features.