Optical Spectroscopic Markers of Cancer

Disease markers have classically encompassed proteins, gene expressions, proteomics and histological abnormalities (dysplasia). Optical properties of the tissue can provide fundamental insights into tissue properties at structural and molecular levels and hence, serve as novel markers of disease. Biophotonics is an emerging field that bridges biomedical optics to medicine. A particularly exciting application of biophotonics is on the diagnosis, detection and screening for cancer. Recently, non-invasive or minimally invasive biophotonics techniques have been developed that sense changes in tissue at molecular, subcellular, microscopic and macroscopic levels. These optical markers are indicative of alterations in tissue morphology, chemical composition as well as functional changes such as changes in microvasculature. In some cases, optical markers have specific histological determinants. In these cases biophotonics techniques may provide a less invasive and fast means of identifying dysplasia (the 'optical biopsy').
Other groups have focused on using optical techniques to assess the genetic/epigenetic correlates of field carcinogenesis and thus these spectral markers can be used for risk stratification. The purpose of this publication is to highlight the spectrum of approaches and the recent advances in the field of optical markers of carcinogenesis.