Fig. 4
Different hallmarks of tumor between HER2low TNBC and HER2neg TNBC. (A) Volcano map shows the DEGs between two TNBC groups of tumor cells. Each point represents a gene; genes marked in orange and blue are highly expressed genes in tumor cells of HER2low TNBC and HER2neg TNBC, respectively. (B) The expression levels of four representative immunoglobulin-related genes in tumor cells of HER2neg and HER2low TNBC, respectively. (C) GO (BP) enrichment pathway analysis of the highly expressed DEGs of tumor cells in the two TNBC groups. (D) Representative images of fluorescent staining for the verification of IGHG4, IGKC, APOD and MUCL1 expressions in breast tumor tissues of two groups of clinical TNBC samples. All scale bars, 50 μm. (E) Quantitative analysis of the intensity of staining of IGHG4, IGKC, APOD and MUCL1 expressed in two groups of breast tumor tissues (HER2low TNBC, n = 5) vs. HER2neg TNBC, n = 5) by fluorescent staining. P value, Student’s t test (∗P < 0.05, ∗P < 0.01, ∗∗P < 0.001, ∗∗∗P < 0.0001). Error bars show SEM of single patients. (F) The overall survival of TNBC patients with different mRNA expression levels of IGHG4, IGKC, IGHG1, SCGB2A1, PTN and MUCL1 using Kaplan–Meier-plotter database. The cutoff values were set as the median expression values of all above genes, and P < 0.05 indicates statistical significance, using logrank test