KLK3 and prostate cancer: The use of microfluidic point-of-care diagnostic devices coupled with paper-based biosensors and optical smartphone colorimetric readout is exemplified by detection of Alpha-fetoprotein (AFP) and Mucin-16 (MUC16) in serum considered potent biomarkers for liver and ovarian cancers [10], and Prostate-Specific Antigen (PSA) for prostate cancer [11].