Prevalence of the SDC4:NRG1 fusion in canine pulmonary adenocarcinoma (cPAC)
Pulmonary carcinoma in humans is the deadliest form of cancer worldwide, causing 1.8 million deaths in 2020. Non-small cell lung cancer (NSCLC) is the most common subtype, accounting for approximately 82% of lung cancer cases in the US. While pulmonary carcinoma in canines is rare, with only 1% of cancers diagnosed being lung cancer, it is lethal: canines diagnosed with NSCLC have a life expectancy of only 3-16 months post-diagnosis. Previous studies identified mutations in HER2 as accounting for 31% of canine pulmonary adenocarcinoma (cPAC) occurrence; additional sequencing has identified a novel, recurrent NRG1:SDC4 fusion in 8% of the cohort. RNA was extracted from 66 frozen canine lung tumors and expanded using primers designed to detect this particular fusion. Out of the samples assayed, five were positive for the fusion and confirmed by Sanger sequencing. Future steps include developing a model system or cell line for SDC4:NRG1-positive cPAC in order to investigate options, therapies, and treatments in canines, such as a drug called Afatinib that is currently used in human NSCLC patients positive for NRG1 fusions.