TJP1 and neoplasm: We hypothesized that monocytes regulated tight junctions and increased permeability, considering the well‐characterized role of tight junctions to stabilize vessel integrity and their dysregulation in the tumor microenvironment.30, 31, 32 When cocultured with monocytes, endothelial cells (ECs) presented a remarkable decrease in both mRNA levels of two tight junction proteins, ZO‐1 and occludin (OCLN) (Figure2a).