Fig. 1.

Clinical characteristics and spectrum of ERBB2 mutations in breast cancer patients and construction of ERBB2 cell lines. (A) Left: follow-up computed tomography (CT) image taken 2 months after initiation of lapatinib treatment, with significant pulmonary metastasis in multiple regions after two cycles of lapatinib treatment. Right: follow-up CT images taken at 4 months after initiation of lapatinib treatment, with more significant pleural effusion. (B) The gene sequencing result of the tumor after 4-month treatment with lapatinib (whole blood sample by means of ctDNA detection). The insertion mutation (c.2339_2340-ins-CGGCTCCCC, p.P780_Y781insGSP) was found in ERBB2 exon 20. The diagram of insertion mutation of ERBB2. Wild type, WT; P780-Y781 mutation, MT. (C) Three groups of lentiviruses were added to the MDA-MB-231 or MCF-7 culture to the validate the transfection efficacy (through observing the fluorescence under a fluorescence microscope). (D) The expression level of ERBB2-WT and ERBB2-MT were determined by western blot.