As the present technology of cancer treatment cannot cure the diseases, a prospective therapy, named 'systemic therapy', brings forth a new trend in cancer treatment. The aptamer-NASBA-based lab-on-a-chip (LOC) for systemic therapy was designed, fabricated and tested as an ultra-sensitive tool to monitor signaling molecular profiling in serum samples. The chip is divided into four parallel functional areas, corresponding to four groups of signaling molecules (i.e. hormones, neurotransmitters, cytokines and tumor biomarkers). The results can help doctors fully understand the body of patients. The chip is modeled on a 384-well microplate, which is completely compatible with common microplate readers in a biological laboratory. It can distinguish 24 signaling molecules in the same blood sample quantitatively and simultaneously. The chip was made of PDMS and silicon with a deposited gold layer, which was coated by aptamers before bonding; then, the LOC was operated by external valves and a vacuum pump. Its performance was demonstrated by detecting the presence of a synthetic peptide, GnRH (gonadotropin-releasing hormone) in artificial samples. The results indicated that the LOC has the potential to quantify traces of biomarkers even at subfemtomolar levels. Compared with our previous immuno-NASBA LOC, the aptamer-NASBA LOC showed an increased sensitivity and better repeatability.