Correlation of the standardized uptake value in FDG-PET with the expression level of cell-cycle-related molecular biomarkers in resected non-small cell lung cancers.

The aim of this study was to clarify the relationship between the maximum standardized uptake value (maxSUV) and the expression levels of cell-cycle-related molecular biomarkers. Thirty consecutive patients with non-small cell lung cancer (NSCLC) were enrolled in the study. Histologically, the tumors included 23 adenocarcinomas and 7 squamous cell carcinomas. Protein expressions of Ki-67, proliferating cell nuclear antigen (PCNA), and p53 were examined by immunohistochemistry. The maxSUV was higher in poorly differentiated NSCLCs than in well-differentiated and moderately differentiated tumors (p <0.05). The Ki-67 labeling index was higher in squamous cell carcinomas than in adenocarcinomas (p <0.05), and also in poorly differentiated tumors than in well-differentiated and moderately differentiated tumors (p <0.01). A positive correlation was found between the maxSUV and Ki-67 expression level (r = 0.687, p <0.001). No correlation was found between maxSUV and PCNA expression (r = 0.214, p = 0.248) or between maxSUV and p53 expression (r = 0.357, p = 0.09). Among the molecular biomarkers, an association was found between the expression levels of Ki-67 and PCNA (r = 0.515, p <0.01). Immunohistochemical staining with Ki-67 in NSCLC correlates with maxSUV. Measurement of the maxSUV by PET is a simple and noninvasive method to determine the biological cancer cell proliferation potential.