In total, 13 studies [16, 19, 21, 28, 29, 35, 41, 44, 45, 47, 48, 51, 53] with a combined sample size of 7721 patients studied the relationship between PFS and β2M in DLBCL patients, revealing a significant correlation between PFS and β2M in DLBCL patients. This evidence concerns the gene B2M and diffuse large B-cell lymphoma.