MMP9 and neoplasm: Moreover, several transcripts of matrix metalloproteases (MMPs), such as MMP2, MMP9 and MMP12, involved in the degradation of extracellular matrix and promotion of metastasis were upregulated in both subpopulations of tissue-resident macrophages when compared to their LP counterparts (Fig. 6f), suggesting a possible contribution of these cells in tumour progression.