NEK2 and breast cancer: Of note, TAI-1 specifically targets NEK2/HEC1, exhibiting minimal to no effect on a range of other kinases tested, such as CHK1/CHK2, Cdk1/Cyclin B, Aurora A/B, mTOR, PI3K, etc. TAI-1 inhibits cellular growth at the nM level for most cancer cell lines screened, including breast cancer, liver cancer, colon cancer, leukemia, and others.