Abstract 4925: Development of a novel PTK7 immunohistochemistry (IHC) assay and analytical validation in epithelial malignancies of lung, breast and ovary

An immunohistochemistry (IHC) assay was developed to detect protein tyrosine kinase 7 (PTK7) membrane staining in formalin-fixed paraffin embedded (FFPE) human tumors with the intention of selecting non-small cell lung carcinoma (NSCLC) patients, breast cancer (BrCa) patients, or ovarian cancer (OVCA) patients for enrollment in an early stage clinical trial for a PTK7-ADC (antibody drug conjugate) experimental therapeutic. The IHC assay was developed using an anti-PTK7 specific antibody and a panel of five cancer cell lines with a range of constitutive PTK7 expression as characterized by gene transcript and protein based assays. PTK7 messenger RNA (mRNA) and protein levels were highly correlative in the control cell lines in vitro and the corresponding cell line xenografts. A pre-analytic variables study (PAV) using these characterized control cell line xenografts demonstrated that the PTK7 IHC assay was robust to the pre-analytic variables of under-fixation and ischemia. This IHC assay was used to profile PTK7 levels in human lung cancers, breast cancers, and ovarian cancers, and a dynamic range of PTK7 H-scores was detected (see Table 1). The resulting PTK7 H-scores correlated with orthogonal methods for measuring PTK7 protein and gene transcript levels in the human tumors. Table 1.PTK7 H-scoresNumber of SamplesMinimum H-scoreMaximum H-scoreMean H-scoreMedian H-scoreNSCLC3034230117.4117OvCa2424240151151 Citation Format: Pamela M. Whalen, Amy Jackson-Fisher, Pamela Vizcarra, Cory Painter, Steven Pirie-Shepherd, Diane R. Fernandez, Joseph Lee, Eric L. Powell. Development of a novel PTK7 immunohistochemistry (IHC) assay and analytical validation in epithelial malignancies of lung, breast and ovary [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4925.