Conversely, the five downregulated co-expressed genes showed a significant negative correlation with breast cancer, with ORs and CIs as follows: PIK3R1 (OR = 0.881; 95% CI: [0.806~0.962]; p = 0.005), PNPLA2 (OR = 0.920; 95% CI: [0.866~0.978]; p = 0.007), ATOH8 (OR = 0.960; 95% CI: [0.928~0.993]; p = 0.018), TTC23 (OR = 0.936; 95% CI: [0.883~0.992]; p = 0.028), and CWF19L2 (OR = 0.956; 95% CI: [0.919~0.993]; p = 0.021). Here, PNPLA2 is linked to breast cancer.