Furthermore, the mRNA expression of SIX2 (OR: 1.70, 95% CI: 1.31–2.21; P = 0.669 and I2 = 0.0%; Fig. 5B) and SIX3 (OR: 2.53, 95% CI: 1.91–3.36; P = 0.879 and I2 = 0.0%; Fig. 5C) was statistically higher in basal-like tumors than in the luminal subtype of breast cancer, while that of SIX1 (OR: 0.56, 95% CI: 0.43–0.73; P = 0.949 and I2 = 0.0%; Fig. 5A) was obviously lower in basal-like breast cancer in comparison with luminal subtype. This evidence concerns the gene SIX2 and breast cancer.