Next-Generation Sequencing Assisted in Establishing the Diagnosis and Treatment for a Chinese Patient With Breast and Lung Multiple Primary Malignancies

Abstract Introduction A case of primary lung cancer was reported, which was misdiagnosed as breast cancer metastasis to the lung based on pathology in combination with a history of breast cancer. Methods The common driver gene mutation was detected in different lesions by next generation sequencing (NGS), and it was shown that the genomic profiling of lung lesion and breast lesion were inconsistent. Results The typical driver mutation of EGFR L858R in lung cancer was found in lung lesion, and the patient received the first-generation EGFR-TKI, icotinib, as treatment and achieved a partial response. Conclusions With NGS detection in this case, the specific driver gene in the tumor site was identified, which facilitated the diagnosis of a double primary cancer, and resulted in a change in treatment.