TIMP1 and prostate cancer: Our results showed that increased expression of TIMP-1 significantly promoted growth of PC3, 22RV1, and LAPC-4 prostate cancer cells in vivo (Figure 2B-E) and the promotive effect of TIMP-1 is more potent on 22RV1 and LAPC-4 cells, presumably due to the lower endogenous level of TIMP-1 in these cells comparing to PC3 cells.