The present Inventors demonstrated that the RelB subunit of NFκB plays a crucial role in promoting cell migration. More precisely, they identified that this pro-migratory activity is mediated by the activation of the NFκB pathway through RelB phosphorylation at serine 472. In a first aspect, the present invention proposes to monitor the activation of the NFκB pathway by following the phosphorylation status of said serine. Also, the present invention discloses methods and kits for prognosing the evolution of a disease involving cell migration in a subject—treated or not—suffering thereof, based on the detection of said RelB-S472 phosphorylation.