ESR1 and neoplasm: Third, CTSW was the only eQTL gene showing negative correlation with the number of risk alleles at the GWAS SNP, whereas other eQTL genes had the opposite trend, indicating that CTSW may play a tumor-suppressive role in TILs, while others may be involved in promoting cancer progression (linear regression coefficient in BRCA ER + eQTL: CTSW, r = –0.22; FIBP, r = 0.09; MUS81, r = 0.08; EIF1AD, r = 0.05; Figure 1B).