CD4 and neoplasm: As shown in Fig. 11A,B, the expression of GRB2 was significantly negatively associated with tumor purity while significantly positively correlated with immune cells in infiltrating levels, B cells(r = -0.09, P = 4.69e−02), CD8 + T cells(r = 0.4, P = 2.08e−20), CD4 + T cells (r = 0.118, P = 8.61e−03), macrophages(r = 0.403, P = 1.13e−20), neutrophils(r = 0.493, P = 1.39e−31) and myeloid dendritic cells(r = 0.381, P = 1.79e−18), suggesting that the GRB2 expression was mainly related to the immune infiltration of CD8 + T cells, CD4 + T cells, macrophages, neutrophils and myeloid dendritic cells.