Matrix Metalloproteinase 1 Acts as an Independent Prognostic Biomarker Correlated with Immune Infiltration in Breast Cancer

Matrix metalloproteinase 1 (MMP1) is overexpressed in multiple human tumors. However, the role of MMP1 in breast cancer (BRCA) has not been explored. The relationship between MMP1 expression and immune cell infiltration was conducted using Tumor Immune Estimation Resource (TIMER, https://cistrome.shinyapps.io/timer/), and the survival curve was plotted using Kaplan-Meier with log-rank test. The influence of MMP1 on immune infiltration, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses, immunologic infiltration analysis, and drug sensitivity were conducted through R 4.2.0. Immunohistochemistry (IHC) and immunofluorescence (IF) were used to verify MMP1 expression in BC and the correlation between MMP1 and CD20, CD86 immune cells. MMP1 was overexpressed in BRCA tumors (P < 0.05), and its high expression was related to poor prognosis (P = 0.01). In addition, MMP1 was an independent prognostic biomarker in BRCA. Our findings provide information to further understand the biological functions and signaling pathways of MMP1 in BRCA. IHC and IF have proven the relationship between MMP1 and BRCA. These results implied a critical role of MMP1 in the prognosis and immune infiltration of BRCA. In addition, MMP1 expression participated in regulating multiple oncogenes and tumorigenesis.