PTK7 and invasive breast carcinoma: The functions of PTK7 positively-correlated genes were predicted by the analysis of Kyoto Encyclopedia of Genes and Genomes (KEGG) by DAVID: Functional Annotation Tools (https://david.ncifcrf.gov/tools.jsp) and 9 pathways related to the functions of PTK7 alterations in invasive breast cancer were found (Figure 4B, right panel).