Absolute quantification of potential cancer marker using targeted mass spectrometric analysis of isotope-labeled clinical samples

摘要

MRM enables targeted analysis of proteins of interest in a complex mixture. The mTRAQ technology shows good run-to-run reproducibility as evident by the low standard deviations across the three runs (Table 1). The new labeling technique permitted the absolute quantification of the protein of interest in homogenates of clinical tissue samples. We thus established that the protein of interest in this case was present at between 20 - 25 nmols/g of total protein in the control samples and was present at a minimum of 80 nmols/g of total protein in the cancer tissue. As seen in Fig 4, the other two cancer tissue samples (cancer 1 and cancer 2) showed significantly higher amounts of the protein.