Fig. 1
From: Serum microRNA signatures and metabolomics have high diagnostic value in gastric cancer
Flow diagram of trial selection. Abbreviations: CEA, carcinoembryonic antigen; CA19–9, carbohydrate antigen 19–9; qRT-PCR, quantitative reverse-transcription polymerase chain reaction; GC/MS, gas chromatography/mass spectrometry; PCA, principal component analysis; PLS-DA, partial least squares-discriminate analysis; OPLS-DA, orthogonal partial least squares-discriminant analysis