Aberrant sialylation of
glycoproteins has been detected in many
tumors, and upregulation of the beta-galactosamide alpha-2,6-sialyltransferase 1 (ST6GAL1) has been implicated with
tumor aggressiveness and chemoresistance in experimental models. In our present study, we aimed to study the prognostic or predictive role of ST6GAL1 in ovarian
carcinoma, using two independent
ovarian cancer cohorts. ST6GAL1
mRNA levels were retrieved from a publicly available database (n = 517), and ST6GAL1
protein levels were analyzed by western blot analysis in a cohort of 204 ovarian
tumor samples. The results were correlated with clinical and histological
tumor parameters and follow-up information. High ST6GAL1
mRNA levels significantly correlated with lymphovascular invasion and shorter survival, whereas high ST6GAL1
protein expression was associated with advanced stage, distant
metastasis and shorter recurrence-free intervals. In both cohorts the prognostic role was most pronounced in
tumors without macroscopically visible
residual tumor after surgery. In these cases, ST6GAL1 expression levels might help to identify cases with a higher risk of chemoresistance and metastatic relapse that might require an adapted therapeutic regime.