Analysis of gene expression profiles of hepatocellular carcinomas with regard to ¹⁸F-fluorodeoxyglucose uptake pattern on positron emission tomography

Purpose: ¹⁸F-fluorodeoxyglucose (FDG) uptake on positron emission tomography (PET) scan has been found to reflect tumour aggressiveness and prognosis in various types of cancer. In this study, the gene expression profiles of hepatocellular carcinomas (HCCs) were evaluated to determine whether HCCs with high ¹⁸F-FDG uptake have more aggressive biological potential than those with low uptake. Methods: Surgical specimens were obtained from ten patients with HCC (six males and four females, age range 38-68 years). The tumour samples were divided into two groups based on the ¹⁸F-FDG PET scan findings: high ¹⁸F-FDG uptake (n=4) and low ¹⁸F-FDG uptake (n=6). Results: The pathological tumour grade was closely correlated with the ¹⁸F-FDG uptake pattern: HCCs with high ¹⁸F-FDG uptake were pathologically Edmondson-Steiner grade III, while those with low uptake were either grade II or grade II with a focal area of grade III. The total RNA was extracted from the frozen tissues of all HCCs (n=10) and adjacent non-cancerous tissue (n=7). The gene expression profiles were evaluated using an oligoD-NA microarray. The HCCs with high ¹⁸F-FDG uptake showed increased expression of 11 genes - including vascular cell adhesion molecule-1, vinexin beta and core 1 UDP-galactose:N- acetylgalactosamine-alpha-R-beta 1,3-galactosyltransferase and the natural killer cell inhibitory receptor - compared to those with low uptake (p<0.005). Nine genes, including regulator of mitotic spindle assembly 1, grb2-related adaptor protein and beta-1,3-n-acetylglucosaminyltransferase, were repressed. Conclusion: Gene expression is closely related to cell survival, cell-to-cell adhesion or cell spreading; therefore, HCCs with high ¹⁸F-FDG uptake appear to have more aggressive biological properties than those with low uptake.