SMAD2 and Alzheimer disease: Even though none of the listed genes encoded proteins typically involved in the immune response, the transcripts showing differential expression between AD and healthy dogs were directly or indirectly connected with transcriptional regulation (SMAD2, RORA) or signal transduction pathways (e.g., VEGF, SHB21, PROC) taking part in T lymphocytes lineages differentiation and cytokines synthesis.