Fig 2: The verification of protein expression of IGFBP4 and TAGLN by the immunofluorescence assay. Protein expression of (A) IGFBP4 and (B) TAGLN in the osteosarcoma was lower than the normal. (*P < 0.05).

Fig 3: Verification the strong predictable value of IGFBP4 and TAGLN for the osteosarcoma via the support vector machine (SVM). (A) Verification sample comparison. (B) Absolute error (C) Error histogram with 20 bins. (D) Percentage of error. (E) In the scatter fitting diagram, the relationship between the predicted value and the actual value is that: y = 0.9117*x + 0.1481, R2 = 0.9892, r = 0.9988.

Fig 4: RT-qPCR for hub genes. The relative expression levels of IGFBP4, SERPINE1, ANPEP and TAGLN were significantly lower in the osteosarcoma group compared with the normal group. However, the relative expression levels of LYN, TNC, TGFB2, and IGFBP1 were significantly higher in the osteosarcoma group compared with the normal group. (*P < 0.05).

Fig 5: The protein expression of IGFBP4 and TAGLN in the osteosarcoma by the Human Protein Atlas. (A) Protein expression of IGFBP4 in the osteosarcoma was lower than the normal. (B) The protein expression of TAGLN in the osteosarcoma was lower than the normal (*P < 0.05).