TMPRSS2 and prostate cancer: For example, the cell lines CWR-R1 and LNCaP-19 both showed elevated levels of AR expression, but low levels of KLK3, while LNCaP-C4-2 and LAPC4 cell lines had low levels of AR expression but high levels of KLK3. Finally, expression of ERG (see green arrow, Fig. 1A) was also not highly correlated with expression of TMPRSS2, which is unexpected since these genes are fused in a high percentage of prostate cancers.