Fig. 1: Accumulation of MGAT1, a glycosyltransferase, is dramatically associated with an unfavorable tumor immune response and prognosis in immune-cold breast cancers.

a Heatmap showing hierarchical clustering of row-scaled breast cancer gene expression data from TCGA for a subset of immune-related genes differentially expressed in four breast cancer types. Each column represents a sample; each row represents a protein. b, c Distribution of single sample GSEA scores of BLBC separated by immune subgroup (immune suppressive subgroup, n = 28; immune active subgroup, n = 125), using gene sets involved in immune functions (b) and glycosylation (c). P-values are from two-sided Wilcoxon tests. Box plots are defined as follows: center line indicates the median (middle line), box bounds are 25th and 75th percentile, and whiskers extend to 1.5*interquartile range below the 25th percentile (minima) and above the 75th percentile (maxima), with outliers outside of that range shown. d Pearson correlation plot showing correlations between N-glycosylation genes (y-axis) and immune-related genes (x-axis). N-glycosylation genes are ordered from top to bottom by the number of significant positive correlations. White cells indicate no statistically significant correlation. e Breast cancer TMA stained with anti-MGAT1 antibody and representative pictures of different breast cancer subtypes are shown. Right: quantified TMA consisting of adjacent normal breast tissue (n = 18), Luminal A (n = 68), Luminal B (n = 41), HER2 + (n = 43), and TNBC (n = 54) samples immunostained for MGAT1. f Expression of MGAT1 in normal human mammary epithelial cells and various subtypes of breast cancer cells detected by immunoblotting using anti-MGAT1 antibody. g Representative composite image (left panel) with inset (right) of a breast cancer specimen (n = 41) stained by multicolor IHC comprising CD8, Ki67, CD3, MGAT1, PanCK, and DAPI. Scale bars: 100 μm. h Touching events between CD3⁺CD8⁺ T cells and PanCK⁺ tumor cells, or CD3⁺CD8⁺Ki67⁺ T cells and PanCK⁺ tumor cells among MGAT1hi relative to MGAT1lo tumor regions (n = 44) were measured with R-based PhenoptrReports & Phenoptr. i Kaplan-Meier curves of TNBC and BC patients corresponding MGAT1 expression. The high MGAT1 expression leads to poor prognosis in both TNBC and BC patients. Data (represented as means ± SEM), images, and western blots are representative of three independent experiments. Statistical significance was determined using two-sided Wilcoxon tests (b, c), one-way ANOVA with Tukey’s multiple comparisons test (e) or two-tailed paired t test (h), or two-sided logrank test (i). Source data are provided as a Source Data file.