CCR2 and glioma: The rs7853346 polymorphism in long non coding (lnc) RNA-PTENP1 and the rs1799864 polymorphism in chemokine receptor (CCR)2 could independently affect cognitive impairment after RT, while a more significant combined effect on cognitive impairment was exerted in glioma patients via the signaling pathway of PTENP1/miR-19b/CCR2.