ST14 and prostate carcinoma: Furthermore, we found that similar suppression of matriptase activation in the insoluble fraction prepared from 184 A1N4 cells could be suppressed by adding the cytosolic fraction from a variety of differing cell types such as the prostate cancer cells LNCaP (Fig. 5A, lanes 7 and 8) and PC3 (Fig. 5A, lane 10).