SMAD4 and Keratoconjunctivitis sicca: In dry eye, 39% of altered pathways were related to cellular growth and differentiation; that is, there were decreases in proteins that participate in the hippo pathway, a core pathway regulating organ size, cellular proliferation, and differentiation that includes transcription factors YAP1 (p = 0.009), TEAD1 (p = 0.005), and SMAD4 (p = 0.006).