MKI67 and neoplasm: Moreover, Spearman rank correlation analysis showed that CTCs counts were highly correlated with tumor differentiation (r = 0.432, P = 0.005), lymphovascular invasion status (r = 0.643, P < 0.001), perineural invasion status (r = 0.725, P < 0.001), Ki-67 level (r = 0.677, P < 0.001) and TNM stage (r = 0.789, P < 0.001) (Table 2).