Relationship between fluorodeoxyglucose uptake and overexpression of glucose transport protein 1 and hexokinase-Ⅱ in early-stage nasopharyngeal carcinoma

Objective To discuss the molecular mechanism of 18F-fluorodeoxyglucose (FDG) uptake in tumor and to assess its value to identify pathologic type and cancer staging in patients with earlystage nasopharyngeal carcinoma.Methods Forty patients with nasopharyngeal carcinoma of early-stage,including 12 cases with T1 stage and 28 cases with T2 stage, underwent FDG PET imaging.The maximum standardized uptake value ( SUVmax ) and mean standardized uptake value ( SUVmean ) of FDG uptake of each patient were measured and compared between T1 and T2 stage by t-test.The expression of glucose transport protein 1 ( Glut1 ) and hexokinase- Ⅱ ( HK- Ⅱ ) of each case was measured in paraffin sections by streptavidin-perosidase (SP) immunohistochemistry.The positive expression rate of Glut1 and HK- Ⅱ was calculated and compared between T1 and T2 by x2 test.Meanwhile, the correlation between the expression of Glut1 or HK-Ⅱ and the SUVmax was tested by Pearson analysis.Results The SUVmax and SUVmean in 40 patients were 9.45 ± 1.87 and 6.04 ± 1.09, respectively.The SUVmax of patients with T1 stage (8.95 ± 1.91 ) was significantly lower (t =4.46, P＜0.001 ) than that of patients with T2 stage (11.55 ± 1.70), and the SUVmean of patients with T1 stage (5.61 ± 1.08) was significantly lower ( t = 6.76, P ＜ 0.001 ) than that of patients with T2 stage (7.98 ± 1.10) too.Among 40 patients, all patients showed positive expression of Glut1 and HK-Ⅱ , and the positive expression rate of Glut1 and HK-Ⅱ was ( 45.2 ± 10.9 )% and ( 68.3 ±9.5)%, respectively.The positive expression rate of Glut1 was (38.4 ±8.1)% in T1 stage and (49.7 ±12.6)% in T2 stage, which displayed no difference (x2 =40.58, P＞0.05), but the HK-Ⅱ positive expression rate showed significant difference (x2 =58.71, P＜0.05) between T1 stage (60.1 ±11.1)% and T2 stage (77.9 ± 14.7 )%.The correlation analysis indicated that there was low-degree positive correlation (r =0.369, P=0.019) between the SUVmax and Glut1 expression, and there was medium-degree positive correlation (r = 0.549, P = 0.001 ) between the SUVmax and HK-Ⅱ expression.Conclusion Expression of Glut1 and HK-Ⅱ was positively correlated with FDG uptake in patients with early-stage nasopharyngeal carcinoma.