TNF and osteoarthritis: The results of IPA analysis identified the osteoarthritis pathway as the most highly enriched canonical pathway among these dysregulated genes, with 23 differentially expressed genes involved in this pathway (p = 4.72 × 10−10, Z score = 1.342), and tumor necrosis factor (TNF) as the most highly predicted upstream regulator (p = 2.20 × 10−22, Z score = −0.159).