Rusz O, et al. - Researchers ascertained the relationships between lysosomal-associated transmembrane protein 4b (LAPTM4B) gene copy number and response to different chemotherapy regimens in hormone receptor negative (HR-) primary breast carcinomas. Findings confirmed that LAPTM4B gene could have a possible role in anthracycline resistance in hormone receptor negative (HR-) breast cancer. Future treatment decision could be supported by the analysis of LAPTM4B copy number pattern. A significant difference of average LAPTM4B copy number between the non-responder and pathological complete responder groups was seen.