TREM2 and amyotrophic lateral sclerosis: Fourteen genes were identified in two or more ALS-related publications with frequencies that were significantly different from those in over 20 million abstracts in PubMed (p<0.05). Fifty-one genes demonstrated ≥2-fold altered expression, including the chitinase 3-like protein 2 (CHI3L2), the triggering receptor expressed on myeloid cells-2 (TREM2), cathepsin Z (CTSZ), the lumican precursor protein (LUM), H19, and TRAIL/TNFSF10 (Tables 2, 3).