SUVmax of 18F-FDG PET/CT correlates to expression of major chemotherapy-related tumor markers and serum tumor markers in gastric adenocarcinoma patients

Abstract

The expression of P53 was previously found by us significantly correlated with maximal standardized uptake value (SUVmax) in non-small cell lung cancer (NSCLC) patients. Hence, the aim of this study was to clarify the relationship between SUVmax and the status of the chemotherapy-related tumor marker expression or serum tumor markers in gastric adenocarcinoma patients. Sixty-four gastric adenocarcinoma patients who underwent 18F-FDG PET/CT prior to treatment were enrolled in this study. Immunohistochemistry was performed to detect changes of Her-2, P53 and Survivin in lesions, and electrochemiluminescence (ECL) method was used to quantify expression of serum CA72-4, CA19-9 and CEA of these patients. Then, the relationships between these parameters above were assessed by Spearman correlation analysis. Also, receiver-operating characteristic (ROC) curve was performed to determine the best cut-off value of SUVmax for suggesting chemotherapy resistant tumor markers. Besides, we identified a linear correlation to estimate the equations between SUVmax and the serum tumor markers. Our results showed that higher SUVmax was detected in patients with positive expression of Her-2 and P53, compared with negative groups. The Spearman correlation analysis showed that SUVmax was associated with Her-2 or P53 with the moderate relevant Pearson correlation coefficient. ROC curve analysis showed that the sensitivity and specificity of SUVmax for suggesting Her-2 or P53-positive, when the cut-off value of SUVmax was set at 3.25 or 5.45, respectively. Moreover, the relationship between SUVmax and serum tumor markers were analyzed by linear correlation analysis, and serum CA72-4 and CA19-9 could be used as independent parameters to establish an equation for SUVmax by the linear regression models. These results suggested that SUVmax of 18F-FDG PET/CT could be used to predict and evaluate Her-2 or P53 related chemotherapy resistance of gastric adenocarcinoma patients. However, before PET/CT scanning, serum tumor markers could be used to calculate the SUVmax approximately.