A recent report showed that AP4 promotes oncogenic phenotype and drug resistance in breast cancer through the regulation of a novel oncogene, lysosomal-associated protein transmembrane-4 beta (LAPTM4B) (Wang et al., 2018), and induces prostate cancer proliferation though l-plastin regulation (Chen et al., 2017). The gene discussed is LAPTM4B; the disease is prostate cancer.