Neuroendocrine carcinomas: Cytological mimics and diagnostic dilemmas

Unravelling the conundrum of nucleolar NR2F1 localization using antibody-based approaches in vitro and in vivo

As a transcription factor, NR2F1 regulates spatiotemporal gene expression in the nucleus particularly during development. Aberrant NR2F1 causes the rare neurodevelopmental disorder Bosch-Boonstra-Schaaf Optic Atrophy Syndrome. In addition, altered NR2F1 expression is frequently observed in various cancers and is considered a prognostic marker or potential therapeutic target. NR2F1 has been found in both the nucleus and nucleoli, suggesting a non-canonical and direct role in the latter compartment. Hence, we studied this phenomenon employing various in vitro and in vivo models using different antibody-dependent approaches. Examination of seven commonly used anti-NR2F1 antibodies in different human cancer and stem cells as well as in wild type and null mice revealed that NR2F1 nucleolar localization is artificial and has no functional role. Our subsequent comparative analysis demonstrated which anti-NR2F1 antibody best fits which approach. The data allow for correct data interpretation and underline the need to optimize any antibody-mediated technique.