The proportion of cells co-expressing Phlpp1 and clCasp3 was increased with varying degeneration grades in both NP (R2 = 0.933; p < 0.001) and AF (R2 = 0.638; p = 0.018) tissues (Fig. 3d), suggesting Phlpp1 as an important contributor to the progression of human IDD via apoptosis. The gene discussed is PHLPP1; the disease is intervertebral disk degenerative disorder.