Lung cancer remains the most common cause of cancer-related death worldwide and it continues to lack effective treatment. The increasingly large and diverse public databases of lung cancer gene expression constitute a rich source of candidate oncogenic drivers and therapeutic targets. To define novel targets for lung adenocarcinoma (ADC), we conducted a large scale meta-analysis of genes specifically overexpressed in ADC. We identified an eleven-gene signature that was overexpressed consistently in ADC specimens relative to normal lung tissue. Six genes in this signature were specifically overexpressed in ADC relative to other subtypes of non-small cell lung cancer (NSCLC). Among these genes was the little studied protein tyrosine kinase PTK7. Immunohistochemical analysis confirmed that PTK7 is highly expressed in primary ADC patient samples. RNAi-mediated attenuation of PTK7 decreased cell viability and increased apoptosis in a subset of ADC cell lines. Further, loss of PTK7 activated the MKK7-JNK stress response pathway and impaired tumor growth in xenotransplantation assays. Our work defines PTK7 as a highly and specifically expressed gene in ADC and a potential therapeutic target in this subset of NSCLC.