These RA-influenced genes, in turn, positively affect HNC: CDC42 (5 references; q = 7.74 × 10−4), CTSK (4 references; q = 0.0032), CXCL11 (4 references; q = 0.0032), and CYP2C19 (4 references; q = 0.0032). This evidence concerns the gene CYP2C19 and rheumatoid arthritis.