We have adapted the biosensor for the rapid (15 min to result), sensitive (< 200 femtomolar) and specific (low non-specific binding) detection of carcinoembryonic antigen (CEA), a cancer biomarker. Whereas the presence of this antigen in serum is indicative of several cancerous and non-cancerous conditions, its presence in the aspirate fluid extracted from the breast is a definitive indicator of breast cancer (BC). However, detection of the antigen in the protein rich nipple aspirate fluid (NAF) is a challenge because of the small sample size (1-50 microliter). We have completed a pilot study of 15 serum samples and 5 NAF samples from individuals with abnormal mammograms. The CEA concentrations measured have been sent to our collaborators at the City of Hope Hospitals in California for corroboration. In addition, we are currently developing a multi-channel waveguide, which will allow us parallel evaluation of three different biomarkers. We hope to develop assays for a suite of BC biomarkers for simultaneous detection on the multi-channel waveguide. This will provide a more comprehensive diagnostic tool and can serve as a supplement to the current BC detection methods such as mammograms.