In the low-grade gliomas (LGGs), the mRNA expression of COL1A2 and SAMD9 was positively associated with the abundance of B cells (COL1A2: r = 0.163; SAMD9: r = 0.506), macrophages (COL1A2: r = 0.333; SAMD9: r = 0.551), and DCs (COL1A2: r = 0.297; SAMD9: r = 0.571) (P < 0.05, Figure 3). Here, COL1A2 is linked to central nervous system cancer.