¹⁸F-fluorodeoxyglucose uptake predicts MET expression in lung adenocarcinoma

Figures & data

Figure 1 Immunohistochemical analysis showed positive staining: (A) MET, (B) GLUT1, and (C) PKM2 (magnification ×400). Scale bar: 50 μm.

Abbreviations: GLUT1, glucose transporter 1; PKM2, pyruvate kinase M2.

Figure 2 Kaplan–Meier survival analysis according to MET expression. Graph shows that survival time in patients with positive MET expression (n=17) was significantly lower than that in patients with negative MET expression (n=32, P=0.040).

Table 1 Relationship between MET expression and clinical-pathological characteristics (n=57)

Variable	MET expression		P-value
	Negative (n=36)	Positive (n=21)
Age, years			1.000
<60 years	16	10
≥60 years	20	11
Gender			0.520
Male	22	11
Female	14	10
Tumor size (cm)			0.560
<3.0	25	13
≥3.0	11	8
Tumor differentiation			0.089
Well	14	5
Moderate	12	4
Poor	10	12
Pathological N stage			0.037
N0	27	10
N1	9	11
TNM stage			0.081
I + II	27	11
III + IV	9	10
SUVmax			0.002
Mean ± SD	4.60±3.00	9.92±6.62

Abbreviation: SUV_max, maximal standardized uptake value.

Figure 3 Receiver operating characteristic (ROC) curve analysis of SUV_max (maximal standardized uptake value) to predict MET expression. With an SUV_max of 6.2 as the threshold, sensitivity and specificity in the prediction of MET expression were 66.7% and 75%, respectively. The area under the ROC curve was 0.751 (95% CI: 0.609–0.892, P=0.002).

Table 2 Spearman correlation coefficients and P-value between the immunohistochemical staining scores for MET, GLUTI, and PKM2 expression with SUV_max

Variable	SUVmax
	Correlation coefficients	P-value
MET	0.458	<0.001
GLUT1	0.551	<0.001
PKM2	0.176	0.190

Abbreviations: GLUT1, glucose transporter 1; PKM2, pyruvate kinase M2; SUV_max, maximal standardized uptake value.

Table 3 Multivariate analysis of MET expression in 57 patients with lung adenocarcinoma

Parameter	Multivariate analysis		P-value
	OR	95% CI
Age, years	0.963	0.896–1.053	0.307
Gender	0.508	0.130–1.989	0.331
Tumor size (cm)	0.973	0.631–1.500	0.902
Tumor differentiation	0.886	0.360–2.182	0.792
Pathological N stage	1.020	0.191–5.431	0.982
TNM stage	0.584	0.138–2.467	0.464
SUVmax	1.254	1.016–1.548	0.035

Abbreviations: SUV_max, maximal standardized uptake value; OR, odds ratio.

Figure 4 Graphs show influence of MET knockdown on ¹⁸F-FDG (¹⁸F-fluorodeoxyglucose) uptake. Influence of MET on ¹⁸F-FDG uptake in lung adenocarcinoma (A) A549 and (B) H1299 cell lines. MET knockdown by specific siRNA (small silencing RNA) significantly decreased ¹⁸F-FDG uptake in A549 (P=0.035) and H1299 (P=0.010) cells. GLUT1 knockdown by specific siRNA further reduced ¹⁸F-FDG uptake in A549 (P=0.011) and H1299 (P=0.001) cells. However, no additive effect was observed when si-MET was combined with si-GLUT1 in A549 (P=0.708) and H1299 (P=0.764) cells. *P<0.05, **P<0.01.

Abbreviations: GLUT1, glucose transporter 1; NC, negative control; NS, nonsignificant.

Figure 5 Graphs show influence of MET on expression of GLUT1 in lung adenocarcinoma cells. (A and B) Influence of MET on the mRNA levels of GLUT1 in (A) A549 and (B) H1299 cells. MET knockdown by specific siRNA (small silencing RNA) significantly decreased the mRNA levels of GLUT1 in both A549 (P=0.000) and H1299 (P=0.029) cells. (C and D) Influence of MET on the protein levels of GLUT1 in (C) A549 and (D) H1299 cells. MET knockdown by specific siRNA significantly decreased the protein levels of GLUT1 in both A549 and H1299 cells. *P<0.05, **P<0.01.

Abbreviations: GLUT1, glucose transporter 1; NC, negative control.