MKI67 and neoplasm: Furthermore, the ABCG2 profile (r = 0.31, p = 0.0002), chemotherapy (r = 0.58, p < 0.0001), Ki67 expression (r = 0.69, p < 0.0001), tumor progression (r = 0.48, p < 0.0001), and radiotherapy (r = 0.50, p < 0.0001) showed a strong association with tumor grade (Table 2 and Figure 1).