MKI67 and breast cancer: Gene set enrichment analysis was used to explore the role of TEF in the above 408 BC cases and demonstrated that TEF RNA levels negatively impacted cell cycle regulatory genes (Figure 2A, all P < 0.05).30, 31 Further analysis showed that the RNA level of TEF negatively correlates with the mRNA level of Ki67, a common marker of cell proliferation (Figure 2B, P = 0.008).