Analysis of primary synchronous breast invasive ductal carcinoma and lung adenocarcinoma with next-generation sequencing: A case report.

Multiple primary cancers (MPCs) have an increasing incidence rate due to the detection of early stages of cancer and the development of effective therapeutic strategies. MPCs are less common compared with metachronous cancers. Therefore, distinguishing synchronous primary tumors from metastasis and developing an individualized treatment strategy can be challenging. In the present study, the case of a 70-year-old female who was referred to The First Hospital of Jilin University (Changchun, China) with an enlarged left cervical lymph node and no other clinical manifestations is reported. Radiography revealed distinct lesions in the left breast, left cervical lymph node and bilateral lungs. Subsequently, a biopsy was performed in all three lesions and then each specimen was subjected to immunohistochemistry, fluorescence hybridization, amplification refractory mutation system-PCR and next-generation sequencing (NGS). Disease-related enrichment of lymph node mutant genes and Gene Ontology Biological Process enrichment of breast, as well as lung, mutant genes were performed using the Database for Annotation, Visualization and Integrated Discovery. Based on the molecular assessment, the patient was finally diagnosed with breast invasive ductal carcinoma, primary lung adenocarcinoma and cervical lymph node metastatic lung adenocarcinoma. Since primary synchronous breast and lung cancer (SBLC) is rare, a molecular assessment, particularly using NGS, could provide important information for both the diagnosis and treatment of SBLC.