Together, these analyses revealed that COL4A1 expression is highly associated with the infiltration of immune-suppressing cells, such as M2 macrophages, TAMs, and Tregs, suggesting the potential role of high COL4A1 expression in poor prognosis of patients via immune modulation of the TME, at least in the tumor types analyzed in this study. Here, COL4A1 is linked to neoplasm.