Development and verification of a new monoclonal OTP specific antibody for pulmonary carcinoid diagnostics

#3462

Introduction: Histology-based grading of pulmonary carcinoids (PC) is problematic and subject to high interobserver variation. Orthopedia homeobox (OTP) has shown to be an excellent prognostic marker for PCs, also indicated by the WHO. However, absence of a reliable routinely applicable monoclonal OTP antibody (mAb) hampers implementation in routine diagnostics.

Aim(s): To develop and verify a new mAb directed against OTP on FFPE tissue of pulmonary neuroendocrine tumors (pNET) for clinical diagnostics.

Materials and methods: An OTP specific mAb was produced from mice immunised with a recombinant human OTP protein fragment. ELISA positive hybridomas were evaluated using immunohistochemistry (IHC). Following epitope-mapping and isotyping, purified mAbs were validated for IHC in FFPE tissues, the optimal dilution was determined and results were cross validated with the OTP polyclonal antibody (pAb) (HPA039365, Atlas Antibodis). Staining protocols were further optimized for three different automated staining platforms (Dako, Ventana, ThermoFisher) and performance was harmonized using a pNET tissue micro array.

Conference:

Presenting Author: Speel E

Authors: Moonen L, Derks J, Lap L, Marijnissen B, van den Bosch T,

Keywords: Orthopedia Homeobox, pulmonary carcinoid, monoclonal antibody, clinical diagnostics,