Glutamine synthetase immunostaining correlates with pathologic features of hepatocellular carcinoma and better survival after radiofrequency thermal ablation.
OBJECTIVE
Activation of the wnt pathway identifies a subgroup of hepatocellular carcinomas (HCC) with specific epidemiologic and genetic profiles. Wnt activation is predicted by mutation and/or nuclear translocation of beta-catenin and by glutamine synthetase (GS) immunoreactivity. We investigated whether GS staining associates with specific pathologic features of HCC and with survival after radiofrequency thermal ablation.


METHODS
Monoistitutional retrospective-prospective study in a tertiary hospital setting. Two hundred and seven cirrhotics (mean age, 70 years; 63% males, 82.1% hepatitis C virus positive) with early HCC were consecutively treated with radiofrequency thermal ablation (RFTA). Mean tumor size was 2.7 cm; 20.3% of patients had multiple nodules; and median follow-up was 36 months with 54.6% overall mortality. Tumor samples were mainly obtained by biopsy (92,5%) and examined by H&E and immunostaining for beta-catenin and GS. Main outcome measures were overall and tumor-specific mortality by Kaplan-Meier analysis and Cox proportional hazard models corrected for competing risks.


RESULTS
Ninety-one patients (43.9%) had GS-positive HCCs by immunostaining. These tumors had larger size (P = 0.012) and characteristic histology (low grade, pseudoacini, hydropic changes, bile staining, lack of steatosis, and fibrosis). Other clinical or treatment variables were similar between groups. Variables correlating with tumor-specific and overall mortality by univariate analysis were tumor recurrence, advanced disease, posttreatment alpha-fetoprotein levels, and GS staining. Yearly, overall mortality rate was lower in GS-positive patients (12.4 versus 20% yearly; P = 0.006). By multivariate analysis, GS immunostaining correlated with reduced specific (hazard ratio, 0.58; 95% confidence interval, 0.34-0.97) and overall mortality (hazard ratio, 0.62; 95% confidence interval, 0.40-0.96).


CONCLUSIONS
Standard histology and GS status identify a HCC subset with distinct clinical and pathologic features.
Dal Bello
Barbara
B
Departments of Pathology, VI Internal Medicine, and Biostatistics, Istituto Di Ricovero e Cura a Carattere Scientifico-Fondazione Policlinico San Matteo and University of Pavia, Pavia, Italy. enricomaria.silini@unipr.it.
Rosa
Laura
L
Campanini
Nicoletta
N
Tinelli
Carmine
C
Torello Viera
Francesca
F
D'Ambrosio
Gioacchino
G
Rossi
Sandro
S
Silini
Enrico M
EM
D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism; D006528:Carcinoma, Hepatocellular / Q000378:metabolism / Q000401:mortality* / Q000473:pathology / Q000601:surgery*; D017115:Catheter Ablation; D005260:Female; D005500:Follow-Up Studies; D005974:Glutamate-Ammonia Ligase / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D008113:Liver Neoplasms / Q000378:metabolism / Q000401:mortality* / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D016019:Survival Analysis
D014408:Biomarkers, Tumor; D005974:Glutamate-Ammonia Ligase