In total, 26 studies [19, 20, 21, 22, 26, 27, 28, 29, 30, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 46, 47, 48, 49, 50, 51, 52, 53] with a combined sample size of 17 407 patients analyzed the relationship between OS and β2M in DLBCL patients. The gene discussed is B2M; the disease is diffuse large B-cell lymphoma.