Most analyses did not find significant heterogenicity based on Cochran’s Q test and Higgins I2 statistic test, whereas the following analyses showed substantial to considerable heterogenicity, as follows: (1) PLR (p = 0.0499, I2 = 61.0%) of serum MMP-7 in BA diagnosis; (2) sensitivity (p = 0.0015, I2 = 90.0%), specificity (p = 0.0136, I2 = 83.6%), PLR (p = 0.0055, I2 = 87.0%), NLR (p = 0.0014, I2 = 90.2%) and DOR (p = 0.0011, I2 = 90.6%) of serum IL-33 in BA diagnosis (eTable 2in Supplementary materials, page 3). The gene discussed is MMP7; the disease is breast angiosarcoma.