Serum Metabolic Profiling of OSCC
Collected 819 serum samples consisting of 241 HC and 578 OSCC were
divided into a development cohort and a validation cohort for serum
marker discovery and confirmation. There were 367 ions selected to
characterize the global metabolic profiles of HC and OSCC. The average
mass spectra of OSCC and HC are shown in Fig. 1A . From the
average mass spectra, it can be clearly observed that the peaks atm/z 135.0029 (lactic acid, [M+2Na-H]+),
203.0527 (glucose, [M+Na]+), 304.2611 (oleamide,
[M+Na]+) were elevated in the OSCC group compared
to the HC group. More discriminative fingerprint peaks had to be found
by statistical tests, which are described later.
To visualize the difference between HC and OSCC metabolite patterns, an
unsupervised machine learning method, t-stochastic neighbor embedding
(t-SNE), was introduced to reduce the high-dimensional metabolite ions
information into a three-dimensional (3D) feature space. In the
constructed 3D feature space, serum cases from the same group were well
clustered whereas those cases from different groups can be separated
(Fig. 1B ). This result demonstrated there exists a substantial
difference in serum metabolic profiles that can be used for OSCC and HC
prediction.